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1111 Delta NT ManualContents

General OperationPower The Counter 1-1Selecting The Mode 1-2

Leo Mode 1-2Screen Views 1-2Operational Indications 1-2

LEO Mode 1-2Selecting a Layout 1-2Operationallndications 1-3

Adding GPS Coordinates 1-3Recording a Study 1-4Waking the Counter From Sleep 1-4Ending a Study 1-4Transferring Data to a USB Flash Drive 1-4Memory Space 1-5

Road Tube LayoutsTube Positioning 2-1Axle Study Layouts 2-1

Layouts 11and 21 2-2Layouts 31 and 63 2-2Layout 66 2-2Layout 41 2-3Layout 61 : 2-3

Vehicle Study Layouts 2-3Tube Placement 2-4Layouts 51, 52 and 65 2-4


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Table of ContentsLayouts 67 and 68 2-4

Lane Strike Patterns 2-5Tube Spacing Recornrnendations 2-5Special Tube Sets 2-6Regular (Equal Length) Tube Sets 2-6

Using the Right Layout 2-7Sorne Questions to Ask 2-7Layout Surnrnary 2-8

Vehicle Study Layouts 2-8Axle Study Layouts 2-9

For More Information 2-9

Software FunctionsConnecting the Hardware 3-1

USB Cable 3-1Serial Port 3-1

USB to Serial Adapter 3-2Bluetooth Connections 3-2

Counter Clock 3-2File Transfer 3-2Files Presets 3-3Temporary (Next File Only) and Default Settings 3-3Automatic Start 3-3

MaintenanceEnvironmental Hazards 4-1

Moisture 4-1Heat 4-1Shock 4-2Debris 4.2

Battery Maintenance 4-2Recharging 4-2Changing the Battery 4-3

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1111 Delta NT ManualSensors 4-3

Cleaning The Sensors 4-4Sensor Gasket Replacement 4-4Hose Tube Nipples 4-4

Changing the Fuse 4-5Troubleshooting

Counter Operation 5-1LCD screen is blank and no lights are on 5-1No sensor activity indications 5-1Select button doesn't change the layout light.. 5-1An air switch registers more than one hit per axle 5-2A sensor does not register any hits 5-2

LCO Messages 5-2Battery voltage is blinking 5-2BATTERY LOW,CHARGE UNIT 5-2INTERNAL ERROR, SERVICE UNIT 5-2NOGPS SYNC, WAITING 5-2GPS DATASAVED,SUCCESS 5-2CONNECTGPS, WAITING 5-2

OK LEO Codes 5-3Steady blinking 5-3Slow blinking (about once every two seconds) 5-3Two blinks, pause 5-3On (no blinking) 5-3Blinks quickly for five seconds .........................................................5-3Off 5-3

Study Files 5-3Files are not copied onto the memory stick 5-3Study files are not saved on the counter 5-4

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Table of Contents \\\\Technical Specifications

General 6-1Physical Specifications 6-1Operational Specifications 6-3

Appendix A. Data Accuracy and PrecisionCounter Resolution A-1

Speed Uncertainty A-1Axle Spacing Uncertainty A-2

Tube Layout Errors A-3Tubes of Different Lengths A-3Inaccurate Sensor Spacing Measurement A-4

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1111 Delta NT ManualGeneral Operation

PowerThe CounterThe Delta NT has a On/Off switch located at the lower left corner of the counter face. Whenthe counter is not being used, turn it to Off to conserve battery power. Count data is savedeven when power is off or the main battery is removed.If there is nothing showing in the LCDscreen, no lights are on, and the power switch is in theOn position, the unit is probably in sleep mode to conserve power. To awaken the unit, pushand hold the 5tart button until the LCDor lights come back on.The Delta NT uses a rechargeable 6V - 10 amp-hour gel cell battery. It is designed to last over280 days when conducting studies. The counter displays the current battery voltage in the LCDhome screen. When the battery voltage drops to 6.0 volts, the unit should be fully recharged.This usually takes between 24 and 48 hours using a trickle charger. Solong asthe batteryvoltage is 5.8 volts or greater, a new study may be started, but be sure to recharge the batteryas soon as possible. If the battery falls below 5.7 volts, no new studies may be started.

Mode Button

OKLight

Sensor Lights

Start BuUon

USB "A" Port

8 e o ensorsUSB "B" Port ------

Serial Port ----- ..... 5 rn~W. _~__ _ 4-8 A B A B"." "." ."6'-20' 6'-20'A B

51 52BatteryChargingPort----J.L

Select Button

On I Off Switch6'10'D e

A 861 201 65 ~D

A

63ConfigurationLights-----tI""'lII(under each layout) _

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General OperationsSelecting The Mode

\\\\The Delta NT counter has two modes of operation. The LCDmode usesthe LCDscreen at thetop of the counter to display status and information messages. The LEDmode turns off theLCDscreen and usesthe red LEDlights instead. Someinformation, like date and time, are onlyavailable in LCDmode. To use the layout selection function, you must be in LEDmode.Pushthe Mode button on the right side of the counter face will change the counter betweenLCDand LEDdisplay modes. There may be a slight delay while the mode is being changed.LeD Mode

Screen ViewsUsingthe Select button while in LCDmode cycles the LCDscreen through its different views.There are three basic display screens:1. The Home screen--Shows the last four digits of thecounter serial number, the current date and time, and thebattery voltage. If the voltage is blinking, you must rechargethe battery soon.2. Strike Count screen 1--Shows the number of strikesdetected during the first 24 hours and the entire study forSensorsA and B

3. Strike Count screen 2--Shows the number of strikesdetected during the first 24 hours and the entire study forSensorsC and DNote: 24 hour totals are from the time recordinot a midnight-to-midnight count (unless the study was started atmidnight).

The Strike Count screens do not start counting until a recording is started. However, when astrike is detected, you will see the strength of the stike brief1y on the right side of the display.Operational Indications

When the recorder is first powered up, it goes througha series of internal tests. It checks the battery voltage,internal memory, and other diagnostics. At the endof a successful test, the LCDdisplay should show thehome screen. If another message is displayed, DONOTcontinue placing the recorder. Check the Troubleshootingsection or contact TimeMark technical support for moreinformation.LED Mode

r . -

Selecting a LayoutIf you wish, you may select the layout that has been placed before starting a study. This willsave the layout in the file. Otherwise, you can also record the layout in your field notes andenter it into the file later using TimeMark software. The layout selection does not affect howor what data the counter records.

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1111 Delta NT ManualThe Select button changes the sensor layout selection in LEDmode. It will only work if the OKlight is blinking, indicating the unit is ready to be setup. If the OK light is on solid, a study isalready recording and you cannot change the layout.Depressthe Select button to change the selection light to the next layout in a clockwisedirection. If you accidentally passthe selection you wanted, keep depressing the Select buttonto cycle around again.

Operational IndicationsOne layout light should be lit. The sensor lights will blink when a strike is detected. Thecounter does not need to be recording to monitor strike detections this way.How the OK LEDbehaves indicates the current state of the counter:Ilf the OK light .. Then ...Blinks steadily the counter is readyBlinks slowly (about every 2 seconds) the counter is waiting to start automaticallyBlinks twice, pauses, repeats the battery is lowStays on (no blinking) data is being recordedBlinks quickly for 5 seconds a GPSposition has been receivedIsoff (and counter isn't sleeping) the battery is too low to operate, there is ahardware error, or the power is offSee the Troubleshooting section for more information about handling errors.

Adding GPS CoordinatesA GPSdevice may be connected to the counter either prior to or after starting a study. Thecounter can then read its position from the device. If the counter is already collecting data,the coordinates are saved in the current study. Otherwise, the location will be saved in thenext study that is started.Both a serial cable for GPSunit and a TimeMark serial cable or dongle are required. First turnon the GPSdevice and wait for it to find the satellites. If the counter is not on already, turnit on. Connect the GPScable to the device and the TimeMark cable or dongle to the counter.Then plug the two together.When the counter receives a posit ion, the LCDscreen will display the messageGPSDATASAVED,SUCCESS.If the counter is in LEOmode, the OK light will blink rapidly for about five seconds.

WARNING : G PS information is lost if the counter s shut off beforethe study begins.

If they are not entered correctly in the field, TimeMark software allows GPScoordinates tobe added or changed during the transfer of afile from the counter or afterwards. Seeyoursoftware manual for more information.Note: The last GPScoordinates received by tiie counter are saved inthe study fi/e. If the wrong Location was entered, simply reconnectthe GPSdevice to the counter at the correct site. When the counteris turned off, the recording file is finatized. Then you must downloadthe file and usesoftware to make any corrections.

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Recording a Study

General Operations \\\\The Start button is used to begin data collection.With the unit in LCDmode, depress the startbutton to display the confirmation messageon thescreen. Depress the Start button again to begin datacollection. A new screen showing either the date andtime the study started or a reminder to connect a GPSdevice should appear. The Started screen will stay inthe screen rotation until the counter is turned off. If"GPS" appears under "STARTED,"coordinates havebeen saved in the current file.To start a study in LEDmode, select the sensor layout, then depress the Start buttonthree times (1/3 to 1/2 seconds between clicks). There will be a few seconds delay untilrecording actually starts. Wait for the OK LEDto stop blinking and stay on for confirmationthat the study has started before closing the counter lid.

IMPORTANT: If the CONFIRM message on the LCO screen isn'tcleared OR (in LEO mode) the OK light is NOT on solid, you areNOT collecting data!

After the study has begun, the Start button will only wake the unit up from sleep mode. Itwill not stop the collection of data.

Waking the Counter From Sleep

Ending a Study

If no buttons have been pressed for several minutes, the counter will turn off its screenand LEDsto conserve battery power. This does not affect a study being recorded. Depressand hold the Start button for a few seconds to wake the recorder after it has gone intosleep mode. This will turn the displays back on.

To end a study, turn the Delta NToff with the power switch. The data will be saved in thecounter's memory.

Transferring Data to a USB Flash DriveWith the counter power off. insert a memory stick into the USB"A" port. Then turnthe counter on. After it finishes booting up, the unit will check for the drive, then startcopying any files to it that have not been previously downloaded. While it is working, thebusy light on the stick will flash. There may be short pauses between files. The process isnot finished until the busy light stops and stays out. Do not remove the flash drive fromthe counter, or turn the counter off, until you are sure it is finished.

Note: When choosing a f lash drive, look [or an easily visibleactivitv l ight so you can qu;ckly see ;t the counter is accessingthe drive. U3 drives cannot be used ;n NT counters unless the U3component is uninstalted first. Storage size is up to the user, butlarger arives do take longer [or the counter to confirm space on.Werecommend 2 Gb or smaller drives.

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1111

Memory Space

Delta NT ManualStudies are not deleted from the counter after they are transferred to a USBflash drive. Thecounter does mark them, though, so they will not be transferred to a flash drive again. Ifnecessary, it is possible to retrieve all the studies in the counter's memory, marked or not, byputting a file in the root folder of the memory stick named "download.all" (no quotes).Files downloaded onto a stick have an eight character fi lename with a CDFextension. Thefirst four characters are the same as the last four characters of the counter's serial number.The last four numbers refer to the position of the beginning of the study in the countermemory. If the counter detects afile on the memory stick with the same name as afile it istrying to upload, the counter will skip that study and the file on the memory stick will remainunchanged. However, if the rest of the download is successful, all unmarked files, even thosethat were skipped because of their file name, will be marked as downloaded in the counter.Back up and remove files from your USBflash drive regularly. This will speed up yourdownloads as well as make sure you always have enough space. If a memory stick is full, oralmost full, the counter will only upload as many complete files as it can. Then, to be sure allthe files will be uploaded later, none of the files will be marked asdownloaded.

Delta NT units have from 8 to 32 Mb of memory. When a recording reaches the end of thememory, the counter will automatically wrap around to the beginning and continue. Thismeans the oldest study will be overwritten whenever more room is needed. Users do not needto free up the memory themselves. However, you do need to be sure studies are transferredfrom the counter regularly. The oldest study will be overwritten when the space is neededwhether it has been downloaded or not.

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1111-.

Tube Positioning

Delta NT ManualRoad Tube Layouts

This is a guide to help you set up the recorder and road tubes to collect the best and mostuseful data possible. Although there are no guarantees of accuracy when using pneumatic roadtubes, using the right layout for the volume and conditions of the site will directly affect thequality of your study.Whatever configuration you use, be sure to record it in your field notes. It is possible, but notnecessary, to enter the layout number in the counter before you start recording. Otherwise,the layout can be entered into each file as it is downloaded from the counter.

Tube sensors should always be laid so they are parallel to the oncoming axles. Both tires onan axle should strike the tube at the same time. Otherwise, each tire might be counted as aseparate axle.One way to help ensure only one strike per axle is to only extend a tube halfway into thefarthest lane. Then only the tires on the side of the vehicle closest to the counter will strikethe hose. If you are concerned that the end of the tube will be struck in the middle of theroadway, though, you may place the tube all the way across the last lane.

Axle Study LayoutsAxle studies are useful for quick, simple results from sites where the traffic is homogenousor complex layouts would be diff icult to set up. For example, if you know almost all of thevehicles will have only two axles, you can get pretty good results from an axle study layout. Ifyou only need basic gap timing, you could also use this kind of layout.Speed studies using axle layouts only use one sensor and only count two-axle vehicles thatare separated by minimum gaps (4 seconds, for example). That may be adequate for a lowvolume, residential street. But if there will be higher volumes or a wide variety of vehicles, aone-sensor (axle) speed study will only give you a feel for the free-flow speeds, not a completepicture.Most older volume counters do axle volume studies because they do not require manycalculations. An axle volume study simply takes the number ofaxles detected and divides it bythe average number ofaxles expected per vehicle. Note that axle studies are only estimates.They are only as accurate as the average number ofaxles (for volume) or average two-axlewheelbase (for speed) used when analyzing the data.

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Road Tube Layouts \\\\Layouts 11 and 21These configurations use one tube over a single or multiple lanes. Layout 11 only collects datain one channel. Layout 21 is for two independent channels. If a tube crosses multiple lanes,the data may be affected by shadowing, which is where one axle strike obscures another strikeat the same time in another lane. Any gap analysis done on multiple lanes will be combinedgap only.

11

_Ac~

21

Layouts 31 and 63These layouts use sensor pairs to separate axle volurnes into two or four lanes, respectively,One sensor is placed across one or more lanes. Then the second sensor of the pair is placedacross the same lanes plus the additional lanes you want to separate. The number of strikeson the shorter tu be will be subtracted from those on the longer tube to get the count for thefarthest lane. Poor lane discipline may cause counts in the wrong lane. TubeA (and e, forlayout 63) is always the shorter tube of a pair.

31

:A l B- ,- -~

63

Layout 66This layout can count up to four separate lanes. The A sensor is only placed across the nearlane, the second sensor across the first two lanes, the third sensor across three lanes, and thefourth across four lanes. If possible, avoid extending each tube more than halfway into its finallane. If you only need to count three lanes, do not use the A sensor and start with the B tubeacross the first lane.

66-- -1 _ _ _=eB =- -Ar:: -

'-;'--

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1111 Delta NT ManualLayout 41Layout 41 is specif ically designed for counting at low volume and low speed sites such asresidential streets and parking lot entrances. It is especially effective on roads with poor lanediscipline where layout 31 does not work. The expected traffic volume should be low enoughthat it will be rare to have cars going opposite directions striking one sensor at the same time.When that happens, only one strike (and one vehicle) will be detected. Similarly, be cautiousabout using this configuration for more than two lanes because it compounds the problem ofsimultaneous actuations.

41

A B ,-~

The order and timing of the sensor strikes is very important when analyzing data from thislayout for volume. Therefore, it is critical that the hoses be laid out correctly. Place the tubes4 inches apart, or about one palm's width. Be sure that both tubes are EXACTLYhe samelength, including any stretch, and that they are parallel to the vehicle axles.Layout 61This layout is simply four independent sensors. You cannot select it on the counter, but it canbe changed in the file during or after transfer from the counter. It is usually only used forsensor testing.

61-J B t .D -~

Vehicle Study LayoutsWhat vehicle layouts add in effort to set up, they make up for in study result accuracy. Usingpairs of tubes that are a known distance apart for each channel allows software to calculateaxle spacings and classify each vehicle. Youdon't need to know what the mix of vehicle typeswas to get accurate results; that is reconstructed during analysis for you.Vehicle study layouts must be used for classification or per vehicle studies. Other vehicle-based studies include volume, speed and gap. Single tubes can be selected from these layoutsduring processing for axle-based results. This allows some results to be recovered if, forinstance, a tube fails during the study.

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Road Tube Layouts \\\\Tube PlacementThe tubes must be parallel to each other as well as to the vehicle axles. When they are laidout, you must carefully measure and record the distance between them sothey can be enteredinto the file before they are processed. To make sure the hoses are parallel, measure thedistance between them on both sides of the roadway; they should be the same.IMPORTANT: Be sure to write down, or program in, the exactdistance between the sensors if you are using these layouts. Thesoftware needs this measurement in its calculations.

Lay the hoses between 6 and 20 feet (2 - 6 meters) apart. The average speed at the site shouldbe considered when determining the spacing. In general, the faster the traffic, the fartherapart the hoses should be.The accuracy of the analysis results is dependent on the accuracy of the tube spacing andlength. You can see the importance of accurate measurements when setting up the layout inAppendix B. The accuracy of each axle's speed, and thus the spacing between axles, dependson the precision of sensor spacing measurement.Layouts 51, 52 and 65There is no maximum vehicle volume restriction when using two hoses over a single lane.However, if you use any of these layouts acrosstwo lanes, the Average Daily Traffic volume(ADT) should be less than 8,000 to 10,000 vehicles per day, or 500 vehicles per hour. Otherwiseshadowing (multiple simultaneous axle strikes) may become a problem.

51

~- ":: .- I~ - A " ~~ -~

65

l e =DZJ

~ . 1 } lBI

Note: Layout 52 (not shown) is like layout 51, except that it is [orone-way traiiic in a single lane.Layouts 67 and 68There are no traffic volume restrictions when using these layouts over two lanes. Always usea four tube arrangement when higher speeds and volumes are present at the site. This willensure a higher success rate of grouping axles strikes by lane and vehicle.

67

; . ::~ A LB ~ e l D

~

68

When using four tubes to get multiple lanes of vehicle information, it is crucial that they belaid out precisely. Aswith any vehicle study layout, they must be parallel to the axles andto each other. Accurately measuring your tu be spacing is always important, but the spacingsbetween all the tubes is especially critical for this layout.2-4


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1111 Delta NT ManualLane Strike Patterns

Vehicles create two different strike patterns when crossing a layout 67 or 68, depending onwhich lane they are in. A vehicle in the lane nearest the counter crosses all four tubes. TheA and e tube strikes will be used for calculating the vehicle. Matching B and D strikes will becompletely ignored by the analysis so they are not also counted as a vehicle in the far lane.Vehicles in the far lane only cross the B and D hosesand do not conflict with any data from thenear lane.The hoses must be placed in the proper order with correct spacing so that strikes are recordedin the right order by the counter. VIAS, the analysis software, will try to remove a Bstrikeafter an A strike and a Dstrike after a e strike. The Band D tube strikes must be within alimited time window of the short tube strikes.

Tube Spacing RecommendationsTo reduce errors due to tu be strikes being recorded in the wrong order or not close enoughtogether, it is important to measure the distance between the short and long tubes as well asthe distance between the long tubes. The speed of the traffic needs to be considered whendeciding what those spacings should be.Just like any other vehicle study layout, both hoses in a spaced pair need to be the samelength, including any stretch, to get good results (seeAppendix A). A and e are one spaced pairand the B and D hosesare another. But whether the length of one pair is the same as the otheris also important to choosing the correct tu be spacing.

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\\\\oad Tube LayoutsSpecial Tube Sets

The easiest way to aehieve the best aeeuraey is to use Speeial RoadTube Sets. The A and etubes in this set are actually shorter than the long tubes by the width of a lane. Then pulsesfrom an axle strike in the near lane will get to the counter from both the short and long tube atabout the same time.Special RoadTube Sets

Tube SpacingTraffie Speed Between Short and LongTubes Between Long Tubes -b-(->acac


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1111 Delta NT ManualUsing the Right Layout

There are many things to think about before you layout your hoses. Being aware of what eachlayout can do will help you pick the best one for each site.Some Questions to Ask

Is there a lot of traffie at the site?Vehicle study layouts at high volume traffic sites work best with one spaced pair of hoses foreach lane of traff ie. Otherwise, it is more diff icult to separate overlapping vehicles when thedata is processed.

Do you need to know the elass, axle spaeing, speed, or aeeeleration of eaeh vehiele?If so, you must use a vehicle study layout. The spacing between the tubes should be based onthe speed of the traffic and the accuracy you need. See the tables in Appendix A for commonexamples. Carefully measure and record the spacing sothe data will be analyzed correctly.

Whieh way is the traffie moving?All the vehicle study layouts require traffic to cross the tubes in a certain direction. If thehoses are laid out backwards, the data must be corrected before it can be processed. Whenplacing a vehicle study layout, traffic in the lane closest to the counter should strike the A hosefirst.Axle studies do not depend on the direction of the traffic. Layout 41 does separate its countsbased on the order of sensor strikes, but the totals will be the same no matter which sensor isfirst in the near lane.

How many lanes or ehannels of data do you need?Do you only need a total for everything on the road, or will you also need results for each laneor direction of travel? At a site with two lanes, layout 52 will only give one total, and theremay be classification issueswhen vehicles overlap. At the same site, layout 67 will separatethe data for each lane, so vehicle overlap is not a problem.Even if you only need combined totals for a volume or speed study, remember that shadowingmay occur whenever one tube counts more than one lane. If two axles strike the same sensorat the same time, only one will be detected. Then the study will report a lower than actualtotal. This is one of the reasons layout 41 should only be used at low volume sites.

Are the vehieles in well-defined lanes?Any layout that separates multiple channels by extending tubes different distances acrossthe road (31, 63, 66, 67 or 68) relies on vehicles being in one lane or the other. This is calledstrict lane discipline. An example of a site that may have poor lane discipline is a low volumestreet with no center line. When there is no other traffic, some vehicles may drive near thecenter of the road. Layouts that require strict lane discipline might count these vehicles in thewrong lane. For layout 68, being in the wrong lane would be going the wrong direction and thevehicle might not be counted at all.If all tubes cover all the same lanes, where the vehicle is in the road is not important. Theright tubes will always be hit. Layout 41 is specifically used for gathering directional axlevolume where there is poor lane discipline.

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Road Tube Layouts \\\\What kind of reports (volume, speed, gap, classification) do you need?

Vehiele study layouts can be analyzed for any kind of results. Vehiele gap studies only showresults for eaeh lane. However, you can select one sensor from a vehiele layout and analyzeit for a eombined axle gap reporto Axle study layouts eannot be used for per vehiele orelassifieation studies and speed studies are limited.

Might different information about the same site be needed later?Even though you only need a simple axle count now, is it possible someone will request a reporton the speeds or mix of vehiele elasses at the same site? If you use a vehiele study layout, thedata can be reprocessed any way you need. Use an axle study layout if you are sure you willonly need a simple volume count, general speed trends, or a combined gap study (or you willneed to collect new data by the time you need something different, anyway).

Is there a median?Use layout 21, 63, or 65 if you will be placing the counter between lanes. Only layout 65 canbe used for per vehiele results. For axle studies, layout 63 separates the volumes for two laneson each side of the median.

Do you only need the gap time across alllanes?One tube is all you need to measure the gaps in traffie across the whole road. Any layout canbe used for this. Just select the tube that crosses all the lanes to be processed. If you needother information from the same data, ehoose the layout that also supports that.

Layout SummaryThe following tables list the major features of each layout.

Vehicle Study Layouts Required for results based on individually elassified vehieles (rather than est imates) Required for speed studies that inelude all vehieles Data may also be analyzed for axle-only results Spaeing between the tubes must be rneasured and recorded for proper analysis

5 1 5 2 6 5 6 7 6 8Sepa ra te channels 2 1 2 2 2D ire c tio ns o f trave l 2 1 2 1 2N um be r o f tubes 2 2 4 4 4M e d ia n s ep a ra ting o p po site d ire ctio ns o f t ravel XH a nd le s h ig h v olu m es w e ll X ' X " X XTo le ra tes poor lane d iscip line X X XSepa ra te s da ta fro m tw o a dja ce nt lanes X X X

* If there is only one lane of traffic** If there is only one lane of traffic on each side of the median

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1111 Delta NT ManualAxle Study Layouts

For volume studies, the average number ofaxles per vehicle at the site must be well-known For speed studies, only data from free-flowing, two-axle vehicles is needed Per vehicle or classification data will never be required from the data

Lr1 1 2 1 3 1 4 1 6 3 6 6

Sep ar at e c h annels 1 2 2 2 4 4D irec tions o f tra ve l n/a n/a n/a 2 n/a n/aN um b er o f tu be s 1 2 2 2 4 4R oad has a m ed ian X XH and le s h igh vo lum es w e ll X X X X XTo le ra te s p o or la ne d is cip line X X XS e pa ra te s d a ta fro m a d ja ce nt lanes X X *** X X

** * If they are going in opposite directionsFor More Information

Another manual, Road Tube Bastes, is available from TimeMark which covers road tube layoutsin more detaiL Besides hose configurations, it also has tips for choosing the location of yourcounter and information about different kinds of road tube. It is available in the CustomerSupport section of our web site at http://www.timemarkinc.com.

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1111 Delta NT ManualSoftware Functions

NT counters have more functionality than meets the eye. You can record and retrieve yourstudies using just the counter, its controls, and a USBmemory stick. But with a TimeMarkapplication such asVIAS, you can go even farther. The major capabilities are listed here. Thesoftware manual has more details.

Connecting the HardwareSoftware can work with the Delta NT through either its serial port or the USB"B" port. Whichone you use will depend on what you need to do and what you are connecting to.USB Cable

Serial PortWhen you cannot use a USBconnection, you may use thecounter's serial porto The defaultbaud rate is slow (4800 baud) so itwill work with GPSdevices.A TimeMark DB9serial (COM)cableor dongle must be plugged directlyinto the serial porto There is aspecial pinout in these connectorsthat is required to turn the porton. As long as that cable or dongleis plugged in and the power is on,the serial port will be on and usingbattery power.The female end of the TimeMarkcable is plugged into a port on thecomputer.

The fastest connection is available through the counter's USB"B" porto Any USBA-B cable will work. With the counter off,plug the flat "A" end of the cable into your computer and thesquare "B" end into the counter. Then turn the counter on.The first time you connect the counter to the computer andturn it on, you may see a message that new hardware has beendetected. Drivers for the counter's USBto UARTinterfacemust be installed. The TimeMark VIASinstallation includes thedrivers for the Windows 2000 and Windows XPoperatingsystems. If the default drivers cannot be found, WindowsVista users can log in to TimeMark's Customer Support website and download them.To conserve battery power, the USBports turn off after theyhave not been used for several minutes. When this happens,turn the counter off, then back on to wake up the USBports.If a study is recording and you can't turn off the counter, usingthe serial port is your only choice.

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So ftware Functio ns \\\\USB to Serial Adapter

A USBto Serial adapter may be used with computers thatdon't have serial ports. Look for them at the TimeMarkonline store or any retailer that sells computer cables.If you don't buy from TimeMark, be aware that notall adapters are created equal. Those marked as PDAadapters are not recommended.Install the adapter on the computer according to theinstructions that come with it. Someconfiguration maybe needed before it will work with VIAS.

Bluetooth ConnectionsA Bluetooth serial adapter may be used toconnect to the counter wirelessly. Youmustplug a TimeMark Bluetooth dongle into thecounter first. A dongle used for GPSdevicesor a TimeMark cable will not work. Plug theBluetooth adapter into the TimeMark dongle.On the computer, set up the Bluetoothconnection as a serial (COM)port.

You cannot use a Bluetooth USBdongle. The USB "A" port onlyrecognizes memory sticks fordownloading files.

Counter ClockSoftware is the only way to set the date and time on your counters. There is no way to changeit on the counter itself.The counter does not self-adjust its dock. You must connect to the counter every spring andfall if you need to change the dock for daylight savings time.

File TransferTimeMark software gives users more flexibility when downloading files from a counter thanthe automatic USBflash drive transfer. You can review the files on the counter and select onlythose you want. And they can add notes or enter the layout and tube spacing as the files aretransferred.The software can also transfer files that have already been copied onto a memory stick. Filesdo not transfer to a memory stick more than once without forcing all of the studies to beuploaded.

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1111Files Presets

Delta NT Manual

Information about a study can always be edited or added to the data file after it has beensaved on a computer. But if certain information must be saved with afile when it is recorded,you can preprogram some settings in advance. These include site code, a few short notes,layout number and spacing, and channel titles.Advanced presets include the sensor dead time and sensitivity threshold. These can never bechanged after afile is recorded, even with software, because they affect what data is saved. Ifthe counter dead time is too short, that can be corrected during analysis with a longer softwaredead time, but you cannot correct a counter dead time that was too long. These countersettings should only be changed when absolutely necessary and with a full understanding ofhow they will exclude data.

Temporary (Next File Only) and Default Settings

Automatic Start

Settings can be preprogrammed for the next file started only (temporary) or as defaults. Ingeneral, any setting that is different from study to study (like the site code) should be leftblank in the defaults and only ever set temporarily. The default settings would be a good placeto set the most often used layout and tube spacing (if applicable). Temporary settings areerased after a study is started.

This feature allows you to set up a counter in the field without starting it right away andwithout waiting around to start the recording. For example, a counter could be set out duringnormal working hours, but not start recording until midnight.An automatic start time can be up to 27 days in the future. Once it is set, though, you mustleave the counter on. Tocancel an automatic start, turn the counter off. This is a temporary,next fi le only setting.

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1111 Delta NT ManualMaintenance

The Delta NT counter is tough, simple, and easy to maintain. Under most circumstances thecounter will only require minimal yearly maintenance to perform at peak efficiency.

EnvironmEmtal HazardsTo ensure long life and accurate counts, you should be aware of the kinds of hazards that theDelta NT encounters in the day-to-day world of traffic counts. There are four main outsideforces that can wreak havoc on any counter. These are moisture, heat, shock, and debris.MoistureThe Delta NTis adequately sealed against most moisture incursion and should remain dry withthe lid closed even in rain or high humidity conditions. Even so, moisture may still get in thecounter.Dowhat you can to keep moisture out. Check the lid gasket for cuts, shrinkage, or movement.Always use end plugs of some kind in the road tubes to exclude water. Holes in tubes may alsobe a source of moisture that can be "pumped" into the counter asvehicles cross the tubes.The processor board is coated with a moisture barrier to protect it from corrosion. However,too much moisture can still corrode the electrical circuits and the connectors used to powerthe main board and sensors. Avoid allowing water inside the counter at all times. If it's rainingwhen you place the counter, cover the unit with plastic when the cover is open to preventwater from getting into thecounter or do as much of the setup as possible in the shelter ofyour vehicle.If your region is one known for high humidity or rapid changes in temperature, condensation inthe counter may cause corrosion. Placing packets of silicon desiccant in the counter may helpabsorb excess moisture and prevent condensation-induced corrosion.Often the first sign that there is moisture in the counter is found when picking up the unit inthe field. On opening the lid there may be drops of moisture on the inside of the lid gasket orthe display face may have beads of water on it.If you find moisture in the counter, do not turn it on. If the counter is already on, turn it offbefore moving it. Tilt the unit, battery side down, and drain any excesswater out.Take the unit to a dry place. Take off the battery cover and the display face with processorboard. Disconnect the battery, either at the battery or the connector on the processor board.Use an absorbent cloth to blot up moisture from the inside of the case. If it's really wet youmay need to remove the sensor board as well. Do not wipe the processor board with the cloth.Usethe cloth to absorb moisture on the case only. Then allow the entire unit to air dry at least24 hours before attempting to reconnect the battery and turn the unit on.Note: NEVER use compressed air to blow debris or water from anyof the circuit boards.

HeatUnder most circumstances, heat will not be a serious problem for the Delta NT counter. Thecounter is resistant to heat up to around 160 Fahrenheit (lOC). However, placing the unit onpavement with direct sun exposure in the heat of summer has the same effect as baking theunit in an oyen.

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Maintenance \\\\Protecting the counter from excessive heat will also promote battery life. The higherthe internal temperature of the battery, the shorter its life. A battery that stays at roomtemperature and below will last twice as long as a battery that is exposed to temperaturesover 100F (37"C). Batteries that get hotter than 125F (52"C) may last less than 6 months.The original paint on the counter provides the best protection against heat. The light colorreflects a great deal of the sun's energy away from the counter, protecting it from overheating.Setting up the counter in the shade keeps it cooler and may also reduce the risk of vandalismoOut of sight, out of mind.ShockDropping the counter or rough handling can loosen the components and connectors inside thecounter or bend the battery bracket. Long-term rough handling will eventually cause problems.DebrisRubber shreds, water, dirt, spider webs, ants, and other debris can plug the sensors. Keepthings out of the counter that don't belong to ensure the best data collection. Put anenvironmental cap on any unused hose nipple.

Battery MaintenanceThe Delta NTcounter comes with a 6 volt 10 amp hour non-memory retentive gel-cell battery.The battery is a sealed unit and does not require any internal maintenance.The battery voltage is displayed on the LCDhome screen when the counter is turned on. Ifthe battery voltage has dropped to between 6.0 and 5.7 volts, the voltage display will blinkto indicate a low battery condition. A study may stil l be conducted, but the battery should berecharged at the earliest convenient time. If the battery voltage drops below 5.7 volts, theunit will not start.RechargingTo help the battery last as long as possible, charge it on a regular basis. By developing astandard recharge cycle, you can avoid the counter quitting in the middle of a count becausethe battery went dead.With average usage, a fully charged battery in good condition will power the Delta NT counterfor approximately 250 dayswithout a recharge. Try to schedule charging cycles over aweekend on a quarterly basis if possible.Charge the battery with the counter turned off.We recommend you use either the TimeMark GangCharger for charging multiple units at thesame time or our universal charger for individual counters. Both have built-in circuitry thatwill prevent overcharging the battery. Useof other chargers, especially variable voltagechargers, may void your warranty or damage your counter.If you have more counters than chargers, use rotation so that each counter gets charged atleast once every three months. If you run each battery until it is very low and don't rechargethem often, you may save the cost of a charger, but pay in reduced battery life.Recharge the battery when the voltage reads 6.0 volts. Recharging the battery at this level willmaximize the useful life of the battery. At no time should the battery voltage be allowed todrop below 5.3 volts. When the battery drops this low, the life expectancy of the battery canbe cut in half.

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1111

Sensors

Delta NT ManualChanging the BatteryTurn the power switch off. Remove the four screws from the battery cover on the left side ofthe counter. Uft off the battery cover panel and set it aside. This will expose the battery andwires.Using a pair of needle nosed pliers, grasp the negative (black wire) connector firmly and workit off the battery spade. Take care not to grasp or pull the wire when working the connectoroff the battery. The connectors will be tight. If you use your thumb to apply pressure to thepliers, place something between the pliers and your thumb or you may get pinched. Do thesame for the positive (red) side of the battery.Uft the battery out of the case, noting the position and color of the connectors for positive and

negative. Then replace the battery with a new or freshly charged battery. Usethe pliers toline up and push the connectors back on the battery, posit ive connector first, then negative.Warning: Useonly an approved battery. Failure to use the properbattery may cause the counter to fail prematurely or operateimproperly and will void your warranty.

After reconnecting the battery wires, turn the unit on. The L e o screen should show the lastfour digits of the serial number, battery voltage and the date and time. Switching to L E O modeshould turn on the OKand layout lights. If this doesn't happen, it may be necessary to replacethe fuse.If the new battery works properly, reassemble the counter. Take care to guide the batterywires if the display board was removed so they are not trapped under the board. Replace thebattery cover and screw it back on.

The four piezo sensors are mounted on a single circuit board that is connected to the case withthree screws. There are insulating grommets in the board that the screws go through that helpisolate the board from vibrations that may be picked up from the case. On each of the sensorsthere are soft gaskets that form a seal between the case and the sensor.

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Maintenance \\\\Cleaning The SensorsOccasionally debris can get up inside the sensor or in the gasket area and reduce or blockthe pulse from the hose. Everything from rubber shreds, water, and spider nests have beencleaned out of the sensors and tube nipples.The sensor may be cleaned using a cotton swab or a small stiff brush. Compressed gas (thetype used to clean computers) may also be used to blow debris out of the sensor.If the sensor has become severely plugged with debris or damaged with water, it may benecessary to replace it. Sensorsmay be replaced individually or an entire sensor assembly maybe swapped out for a new one. We recommend you send in the sensor assembly for repairs.Always keep caps on your unused sensor connectors. Youshould also test the operation of thesensors at least yearly, or any time a problem is suspected.

Hose Tube NipplesWhen axle strikes are being lost on a single sensor and you have already taken the sensorboard out and can find nothing wrong with it,there may be debris in the nipple. Take a pipecleaner, piece of wire, or extra large paperclip that you have straightened out, and insertit into the nipple from the inside of the case.Pushany debris out of the tube.Never try to clear a blocked tube nipple byinserting anything from the outside of thecounter while the sensors are still installed. Youmay push debris into the sensor or damage thepiezo film inside the sensor.Youshould be able to see light through the tubewhen it is clean. Reassemble the counter andtest it for proper operation.

Sensor Gasket ReplacementOver time, sensor gaskets may become lesspliable and no longer form a good seal. Toreplace the gaskets, remove the three screws,take out the sensor board and peel off the oldsensor gaskets. Wipe the face of each sensorwith a clean cloth to remove any residue orglue from the old gaskets. Don't use any spraycleaners on the sensors themselves as thechemicals may damage the piezo disk.Peel off the protective paper from the newgasket and carefully press the new gasket ontothe sensor. Be sure to center it so that the holein the center of the sensor is not obstructed.Always replace all four gaskets at the same time.

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1111Changing the Fuse

Delta NT Manual

The fuse holder is a "snap" connector. It comes apart by gripping the two ends with your indexfingers and pulling out with them while pushing up on the joint with your thumbs.Once the fuse casing has been opened, the fuse inside is held by clips that are soldered tothe wire. Slip the old fuse free of the clips and replace it with a new one (250 Volt 1Amp).Reassemblethe holder by pressing the two halves together.

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1 1 1 1 Delta NT ManualTroubleshooting

This section contains information on various situations that may happen, how to diagnose theproblem, and what to do to fix it. If you can't find your problem or an answer here, pleasecontact TimeMark (800-454-1015 or [email protected]). Our business hours areMonday through Friday (except holidays) from 7 AMto 5 PMPacific Time.

Counter OperationLeo screen is blank and no lights are on

Check to see that the on/off switch is on.Pressand hold the Start button to wake the recorder up.Check the battery connections and voltage.

No sensor activity indicationsIs the counter sleeping? If the display screen is off and the OK light isn't on or blinking,hold down the Start button for a few seconds to wake the counter up.Which display mode is the counter in? If the LCDscreen is on, the sensors lights willnot flash. In this mode, use the Select button to cycle to the screen to view eachpair of sensors (Aand B or C and D). In addition to displaying the number of strikesdetected on each sensor, the strength of each strike will be displayed briefly as well.To use the sensor lights instead, switch to LEOmode.Are the hosessecurely connected to the right hose nipples?Are the hoses laid out properly in the lanes?Check for a hose problem. Is it pinched or blocked with debris? If one sensor seemsto be working but another isn't lighting up, try switching the "good" hose to the non-functioning sensor. If it lights up, replace or clear the faulty hose.Connect to the counter with your TimeMark software and check the sensor sensitivity inthe advanced dialog of the settings tab. There are three sensitivity threshold levels:

1. LowFor high speed roadways where there is a lot of potential for echoes beingproduced

2. NormalWorks well in most situations, with speeds ranging from 10 to 65 mph (15 to105 k/h)

3. HighBicycles, driveways, and other low speed areas

Select button doesn't change the layout lightIf the OK light and Layout light are both on solid, the Delta NT is collecting data.The layout cannot be changed after recording has started.If the LCDdisplay is on, press the Mode button once to switch to LEDmode.

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T rou blesh ooti ng \\\\An air switch registers more than one hit per axle

Check the road tube to see that it is parallel to the axles.Switch the road tubes to different sensors.

1. If the problem switches sensors, there's a problem with the road tube. Checkfor holes or blockages.

2. If the problem remains with the same sensor after switching tubes, theproblem is with the air switch. Connect with TimeMark software and check thesensitivity and dead time settings. It may also be time for sensor maintenance.A sensor does not register any hits

Switch the road tubes to different sensors.1. If the problem switches sensors, the problem is with the road tube. Check tosee if it is plugged, has holes, or the clamp is too tight.2. If the problem remains on the same sensor, the problem is with the air switch.Connect with TimeMark software to check the sensitivity and dead timesettings. Otherwise, sensor maintenance may be necessary.

Leo MessagesBattery voltage is blinking

The battery voltage is between 6.0 and 5.7 volts. Youmay set out the counter, butrecharge it at the next available opportunity. Usea TimeMark-approved charger. Ifcharging the battery does not clear this message, replace the battery asdescribed inthe maintenance section.BATTERY LOW, CHARGE UNIT

The battery voltage is below 5.7 volts. Youmust recharge the battery before you canrecord any studies.INTERNAL ERROR, SERVICE UNIT

A serious error has occurred. Contact TimeMark for help.NO GPS SYNC, WAITING ...

A GPSunit has been connected to the counter, but it does not yet have a satellite fix.GPS DATA SAVED, SUCCESS

A position has been read from a connected GPSunit and saved. Pressthe Select buttonto clear the message.

CONNECT GPS, WAITING ...The counter has been preset to show a reminder to plug in a GPSunit when a recordingis started. Youcan ignore this message. Pressingthe Select button will remove it fromthe display.

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1111OK LEO Codes

Study Files

Delta NT Manual

When the counter is in LEOmode, how the OK LEOblinks (or not) indicates the counter's status:Steady blinking

The counter is ready to record.Slow blinking (about once every two seconds)

The counter is waiting to automatically start at a preset time. See the VIASUser'sManual for more information.Two blinks, pause

The battery voltage is between 6.0 and 5.7 volts. Youmay set out the counter, butrecharge it at the next available opportunity. Use a TimeMark-approved charger. Ifcharging the battery does not clear this message, replace the battery asdescribed inthe maintenance section.

On (no blinking)The counter is recording.

Blinks quickly for five secondsThis indicates that GPScoordinates have been received and stored.

OffThe battery voltage is too low to operate (less than 5.7 volts), there is no power, orthere is a hardware error. Check your power switch, battery voltage and connections.If it does not seem to be a battery problem, contact TimeMark for help.

Files are not copied onto the memory stickIs there enough free space on the stick? Backup or delete files so there is enoughroom.Are you using a U3 (smart) flash drive? The U3 format does not work with TimeMarkNT counters. Either uninstall the U3 component or use a different flash stick.Did you plug the stick in before turning the counter on? The counter will onlycheck for a flash memory stick right after it starts up.Have the files already been downloaded? The counter will only download afile to amemory stick once. To force the counter to copy all the files, downloaded or not,create afile named "download.all" on the stick and try again. You may also usesoftware to see all the files and which have been marked as downloaded.Can you connect to the counter with software using a USBcable? If the USB"B"port is not working, the USB"A" port probably is not, either. Download your fileswith the serial port and contact TimeMark about counter repair.

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Troublesh ooting \\\\Study files are not saved on the counter

Are you sure the files were recorded? To start a study, the Start button mustbe pressed more than once. If the display does not change to say recording hasstarted (or the O K l ight does not stop blinking after a few seconds in LEOmode),recording has not started. Youmay have not pressed the Start button enough, orpushed it too fast or too slow.Check the batteries. If they are too low, the counter may not be able to startrecording.Are there a lot of files on the counter? Eventually, when the memory is full, newerstudies will start overwriting the oldest ones. Do not use the counter for longtermstorage. Download files and save them regularly.If you are using software to look at the files, have you included the downloadedstudies? Unlessyou check the box to include them, files that have already beendownloaded won't be shown in the list.

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1111

1. General

Delta NT ManualTechnical Specifications

The Delta NTis a self-contained, microprocessor-based data collection recorder that workswith road tube to record the axles of detected vehicles. It is designed for simplicity in fieldoperation with corresponding computer software to aid in the translation of the axle data intovehicle information. The recorder collects timestamped event data that can be analyzed toprovide volume, speed, axle classification, gap, and vehicle information.

A .1.2.

B .1.

2.3.

C.1.2.3.

D .1.2.

A. Manufacture1. All original equipment shall be manufactured in the United States.2. All original equipment shall use solid-state electronics.

B. Warranty1. All equipment shall have a three-year limited warranty.

C. Support1. An 800 telephone number shall be provided for support.

11.Physical SpecificationsSizeThe unit shall not exceed 8" X 9" X 5" (20 x 23 x 13 cm), excluding handle.The unit shall not weigh more than 10 lbs. (4.5 kg) in sheet metal case.PowerThe recorder shall use a rechargeable battery with enough capacity for over 210days of continuous counting with 20,000 vehicles a day on two tubes under normalenvironmental conditions without supplementary charging such asa solar panel.A method of recharging the battery without its removal shall be provided.There shall be an on/off switch for disconnecting the battery when not in use.EnclosureThe unit shall be housed in an aluminum housing with locking mechanism that shall beweather resistant.The battery shall be accessible without removing the other electronic boards.The air switch nipples shall be oriented to hinder water and foreign debris fromentering the air switch.EnvironmentalThe recorder shall operate throughout the range of temperatures appropriate for roadtube.The unit shall not be damaged by temperatures from -30'( to 70'( (-22'F to 158'F).

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~-.,

E .1.2.3.

F .1.

G.1.2.3.

H .1.2.3.4.5 .

6.7.

Technical Specifications \\\\CommunicationsThere shall be an RS-232serial port to allow for file setup such as connection to a GPSunit to download coordinates.There shall be a USB-B(device) port for transferring data with a standard rate of921,600 baud.There shall be a USB-A(host) port so that data can be transferred to flash memorydevices.ClockThere shall be a real-time dock powered continuously by a lithium battery, even whenmain power is off.MemoryThere shall be at least 8 MBof memory standard and up to 32MBpossible.This memory shall be flash so no data is lost when main power is removed.The memory shall be wrap-around so that erasing data manually is not necessary.DisplayThe unit shall have lights to indicate proper operation of the air switches.There shall be one button to start a collection session.There shall be a simple one button method used to select a layout from a visualselection diagram.There shall be a method to observe real-time sensor information with a device attachedto the serial port.The unit shall have a liquid crystal display that shows the time, serial number, batteryvoltage, 24-hour total count, total count, and input strength.While a study is underway, the display shall also show the time the study started.There shall be confirmation when GPSinformation is received.

1. Air switches1. There shall be four air switches.

J. Serial number1. Each recorder shall have a unique serial number which is saved with each study.

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1111 Delta NT Manual11I.Operational Specifications

A. Setup1. There shall be a single-use set of parameters (listed below) that are only used on thenext file created:

a. A sensor layoutb. Sensorspacingsc. A 24 character (alphanumeric) site coded. Four 8 character channel titlese. Three 60 character description fieldsf. Sensitivity and dead time (debounce) for the air switches

2. There shall be a method to set the defaults for all the settings listed above.3. There shall be a method to set a start time in the future.4. There shall be a method to change the baud rate of the serial port.5. The unit shall allow for GPScoordinates and UTC (coordinated universal time) to beadded to the file at any time during its collection through a serial connection to a GPSdevice.

B .1.

2 .

C.1.

2 .

D .1.2 .

E .1.

2 .

VehicleUnit shall allow for the collection of data that can be analyzed to provide vehicleinformation which indudes direction of travel, time of arrival, number ofaxles, axlespacings, axle classification, speed , and leading gap for each vehicle.The resolution of the timings shall be less than 150 microseconds, limiting calculationerror to a maximum of 2 mph on a 60 mph vehicle with a 4 inch sensor spacing.Air switchThe air switch sensitivity shall be adjustable for different site characteristics like speed,road tube length, and tire width.The air switch dead time shall be adjustable from Oto 255 milliseconds.MemoryThe memory shall allow the storage of at least 99 separate fi les.The memory shall store at least 800,000 vehicle record s for a standard two tube layout.Data RetrievalThere shall be an automatic method of transferring either all files or only those thathave not already been uploaded to a USBflash memory device.The recorder shall allow individual files to be downloaded by software any number oftimes.

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1111 Delta NT ManualAppendix A. Data Accuracy and Precision

The quality of data recorded by TimeMark counters depends largely on two things: theresolution of the time data and whether the tubes were laid out appropriately. This appendixdiscusseswhat to expect from vehicle (spaced tube layout) study data.

Counter ResolutionDelta NT and Gamma NT counters can record data in two formats. "Strikes only" is identicalto the older TimeMark Delta 111ounters. "Strikes with strength" saves the relative strengthof each sensor strike. While "Strikes only" files may be smaller for high volume studies, theresolution of the timestamps is higher in "strength" mode.A counter's resolution is the smallest length of time between two events that can be saved. Ashorter length (higher resolution) will mean more precise timing, which leads to more exactcalculations. The resolutions of TimeMark sensor strike event recorders are:

TimeMark Counter ResolutionsCounte r R eso lu tio n (r), s eco nd sD e lta N T and G am m a N T re co rd ing w ith s trength 8/216::::: 0.00012207D elta N T a nd G am m a N T re co rd ing s trik es o nly 6/213::::: 0.00073242D e lta 111De l ta 1,D e lta 11,L am b da , G a mm a 30/213::::: 0.00366211

Table A-1 TimeMark event data resolutionBecause the amount of space used to save time information is limited, some rounding isinevitable. Calculation results may be slightly more or lessthan what actually happened. Formost traffic reporting needs, the size of the uncertainty for each vehicle will be negligibleif the tubes are spaced properly. On average, results for large number of vehicles will beaccurate.An uncertainty tells you the most the calculated number is off by. The actual value may havebeen that much more (or less) than the calculated value, or the difference may be smaller.Any number that uses time in its calculation will have some uncertainty.Speed UncertaintyThe speed of a vehicle is calculated by dividing the distance between the sensors by the timeit took for one axle to move from the first to the second tube. It is good practice to make thetime (spacing) between the sensors much larger than the time resolution. A larger spacing willmean a smaller uncertainty.

V eh ic le s pe e d u nc e rt ainty ( in m p h ) ::::: ~~: ~2 x rwhere v = the speed of the vehicle (in mph)

r = the time resolution of the counter data (in seconds)s = the spacing between the tubes (in feet)

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---~~ -_ . _ . _ - _ ..._--------------------------------------

AppendixA \\\\Using this formula, the following table shows some sample uncertainties in speed calculationsfor Delta NT data recorded with strength:Speed Uncertainty, mph, when recording strikes with strengthSpeed Sensor Spacing(mph) 4 in. 9 in. 5 ft. 10 ft. 15 ft. 20 ft. 25 ft.10 0.05 0.02 0.00 0.00 0.00 0.00 0.0020 0.21 0.10 0.01 0.01 0.00 0.00 0.0030 0.48 0.21 0.03 0.02 0.01 0.01 0.0140 0.86 0.38 0.06 0.03 0.02 0.01 0.0150 1.34 0.60 0.09 0.04 0.03 0.02 0.0260 1.93 0.86 0.13 0.06 0.04 0.02 0.0370 2.63 1.17 0.18 0.09 0.06 0.04 0.04rabie A2 Speed Uncertainty, mph, when recording Strikes with strength

As an example, consider a vehicle crossing tubes that were placed 10 feet aparto If thecalculated speed is 40 mph, there is an uncertainty of 0.03 mph. That means the actualspeed may have been anywhere from 39.97 to 40.03 mph. VIA5 rounds speeds to one decimalplace, so that difference would rarely be noticeable.Axle Spacing UncertaintyThe spacing between two axles on a vehicle is calculated from the time between the axlesstriking the same sensor and the speed of the axles. So, again, there is uncertainty in theresults.

( ( 15 x a + 22 x v x r ) )A xle s pa cing u nc erta inty (in inc he s) = x s - a x 1215 x s - 22 x v x rwhere v = the speed of the vehicle (in mph)

r = the time resolution of the counter data (in seconds)s = the spacing between the tubes (in feet)a = the actual spacing between the axles (in feet)

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1 1 1 1

Tube Layout Errors

Delta NT ManualHere are some uneertainties ealeulated for two axles that were aetually five feet apart:

Spacing Uncertainty for Axles 5 ft. Apart, incheswhen recording strikes with strength

Speed Sensor Spacing(mph) 4 in. 9 in. 5 ft. 10 ft. 15 ft. 20 ft. 25 ft.10 0.3 0.2 0.0 0.0 0.0 0.0 0.020 0.7 0.3 0.1 0.1 0.1 0.1 0.130 1.0 0.5 0.1 0.1 0.1 0.1 0.140 1.4 0.7 0.2 0.1 0.1 0.1 0.150 1.8 0.8 0.2 0.2 0.1 0.1 0.160 2.1 1.0 0.3 0.2 0.2 0.2 0.270 2.5 1.2 0.3 0.2 0.2 0.2 0.2Table A3 Spacing uncertainty [or axles 5 [t. apart, inches, when recordedwith str ike strengtb

Saya vehicle was going 40 mph aeross tubes set 5 feet aparto If the ealeulated spaeingbetween two of its axles is 5 feet, that spaeing might be off, but only by two-tenths of an inchor less. The table shows how uncertainty increases with the speed of the traffie, but decreaseswith larger sensor spacings. The uncertainty is also greater for wider actual axle spacings (a).

There will always be uncertainties in the speed and axle spacing ealculations due to timeresolution, but they are small and easily manageable. They also average out over time andenough vehicles. If the sensors are not laid out correctly, though, all vehicle caleulations willbe incorrecto The amount of the error can be calculated.Tubes of Different LengthsIf two sensors are hit at the same time, the signals should reach the eounter at the same time.But that assumesthe length of the tube from the tires to the counter is the same. If one tubehas more length between the counter and the traffie than the other, the signals from the longersensor will be delayed. Carserossing from the longer tube to the shorter will appear to begoing faster than they really are, and vehicles going the other direetion will appear to be goingslower.

t : . t x vT ub e le ng th s pe ed e rro r ( % ) : :: :: - - x 10 0pxswhere v = the speed of the vehicle

s = the spacing between the tubesM = the difference in length of the sensorsp = the speed of the air pulse in the tube

The variables may be in any units of measurement, as long asv and puse the same units ofspeed and s and M use the same units of distance.

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_. _ _ _ _ ._ . _ _

AppendixA \\\\The following table shows how errors will become larger at faster speeds and/or narrowersensor spacing. These numbers are for l J .f . = 10 feet (3 m) and p = 770.45 (assuming dry air at70F (20e)). The air pulse speed changes with temperature and humidity.

Speed Calculation Error PercentageDue to tube length error of 10 feet (3 m)

Speed (mph) Sensor Spacing (feet)5 10 15 20 2510 2.6% 1.3% 0.9% 0.7% 0.5%20 5.2% 2.6% 1.7% 1.3% 1.0%30 7.8% 3.9% 2.6% 2.0% 1.6%40 10.4% 5.2% 3.5% 2.6% 2.1%50 13.0% 6.5% 4.3% 3.2% 2.6%60 15.6% 7.8% 5.2% 3.9% 3.1%70 18.2% 9.1% 6.1% 4.5% 3.6%Tabie A-4 Speed calculation error percentages due to a tube length error oi 10[eet

In this example, the speeds for all vehicles that were actually going 40 mph will be off by2.08 mph (40 0.052) if the sensorswere 10 feet apart and one tube was ten feet longer thanthe other. The vehicles that strike the longer tube first will appear to be going 42.1 mph andthose going the other direction will be calculated to be going 37.9 mph. There will also beuncertainty in these calculations, but only 0.03 mph (from Table A-1).Inaccurate Sensor Spacing MeasurementAccurate counter data analysis depends on the correct, exact spacing between the sensorsbeing known. Being off by even an inch will affect the calculations. If the spacing used by theanalysis is too short, the vehicles will appear to be going faster than they actually were. If theanalysis distance is longer than was actually laid out, calculated speeds will be too slow.

l 1 sS pe ed e rro r (% ) = - x 100swhere s = the actual spacing between the tubes

6s = the difference between the measured and actual sensor spacings and 6s may be measured in any units, as long as they are the same.

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_ _ _ _ _ __

1111 Delta NT ManualGenerally, the wider the sensor spacing, the lessthe same measurement mistake will affectthe results. Here is an illustration of how much a measurement mistake influences speedcalculations:

Speed Calculation Error PercentageDue to Incorrect Sensor Spacing

Spacing error Sensor Spacing (feet)(inches) 5 10 15 20 25

1 1.7% 0.8% 0.6% 0.4% 0.3%3 5% 2.5% 1.7% 1.3% 1%6 10% 5% 3.3% 2.5% 2%TableA5 Speed calculation error percentages due to incorrect sensor spacing

Suppose vehicles were moving across sensors that were actually laid ten feet (120 inches)apart. If the spacing was incorrectly entered as 121inches, the calculated speedswould allbe 0.8% too slow. At 40 mph, this is a 0.3 mph difference. In contrast, the uncertainty of thecalculation is only 0.03 mph (from TableA-1).

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Road Tube Basics Table of Contents

Layout Basics 1Selecting the Site 1Places to avoid 2Thi ngs to Always Do 3Selecting the Layout 4Layout N umbers 11, 31, 21 4Types of Data: 4Limitations: 5Placement: 5Recommendations: 5Tube Placement: 6Layout Numbers 51, 52 6Types of Data: 6Limitations: 6PIacement: 7Recommendations: 7Road Tubes Layout (Oiagram) 8Layout Number 67, 68 9Types of Data: 9Lirnitations: 9Placement: 9Recommendations: 9Layout #67, #68 10Layout Number 65 12Types of Data: 12Limitations: 12Placement: 12Recommendations: 13Layout Number 41 - 14Types of Data: 14Limitations: 14Recommendations: 15PNEUMATIC ROAD TUBE 15Rubber VS. EOPM 15Inside Oiameter 16Round VS. "O" tube 16Temperature 16Length of tube 16For More Information 17contact us at: 17E-Mail us: 17Our Website: 17


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Road Tube Basics

Layou t Bas ic sSuccessful collection of traffic data is dependent on several factors.Selecti ng the proper layout is one of the most crucial. In this basicmanual of Traffic Data Collection and Road Tube Layouts a short de-scription of each available layout will be discussed. The merits andproper use of each will be explained. Situations where a particular layoutwould not be advisable will also be pointed out.It is not the intention of this mini manual to make you an expert atconducting traffic counts, but hopefully it will increase your success rateand improve the accuracy of the data you collect.

Selecting the SiteMany municipalities have count stations. Some even have maps showinglocation and station number. For these sites most of the guess work hasbeen taken out of the equation. However the field technician should beaware that locations that were fine several years ago may have changed.Before a count is conducted it is always a good idea to survey the site forchanges that may adversely affect the accuracy of the count. Perhaps asignal has been added, or a new housing complex or school has gone in.Any changes occurring in the surrounding neighborhood will affect theusefulness of the data collected.Things as simple as a new construction site a block away can impact thelevel of traffic volumes and throw off an otherwise perfect count. Ofcourse it's impossible for you to know every detail about what may behappening around a particular site. But, by watching out for tell-tellsigns it's possible to avoid many of the pitfalls that can lead to a failedcount.Spend a few minutes looking around before setting out the hoses. Isthere an unusual amount of construction equipment in the area? Arecars queuing up at the new signal over the count area? Will they duringa peak hour? Has a new road been placed within 50 feet of the old countstation? If so it may be necessary to move the station to a new location.Be aware of any special events occurring in the local area during thecount periodo Unless that is the reason for conducting the count, avoidplacing the counter until at least a few days after the event.Because most counts are being performed on an annual or semiannualbasis factors such as school openings and closings can impact some areasmore than others. It's always a good idea to conduct studies in areas thatare not being impacted by other outside forces in any unusual way.

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A TimeMark Incorporated Mini-Manual

One final warning. Watch out for sweepers. Those denizens of the darkswoop out of nowhere and neatly suck up unsuspecting road tubes,ending many a count prematurely. If you work for a municipality it's agood idea to contact the Street Sweeping Supervisor and find out whatthe sweeper schedule is in the area and warn him about potential con-flicts with your setups.

Places to avoidTry not to locate a road tube closer than 40 to 60 feet from an intersec-tion where traffic being counted has already passed through the intersec-tion. This applies especially to intersections that have signals because ofplatooning. When vehicles leave a signal, on the green, the first few carsrun abreast and often create "shadows" that hide the vehicle next tothem. Also placing the tube too close to the intersection tends to getmultiple hits from vehicles turning onto the roadway from an intersect-ing street. This may result in double strikes from front and rear axlesbecause the vehicle hasn't had time to straighten out.

8 '+ ---I

. . . . . . . . .

+

Never place a road tube closer than 100 feet from a stop sign on theapproach side. Allow even more distance if traffic queues up during rushhours. Vehicles are slowing, sometimes braking hard. The stop and go, orslow movement of vehicles during peaks in these zones can adverselyaffect the accuracy of the count.

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~...,.~~

Th ing s to A lw ays D o

Road Tube Basics ~IPlacing the counters too close to stop signs or signals will often lead topremature hose failure from hard braking cars, or loss of counts becauseof slow vehicle speeds or vehicles stopping on one of the hoses.Avoid placing counters in the arch of a curve unless the curve is a verygentle "sweeper". Vehicles passing over the road tubes may registerstrikes for each tire instead of each axle.Try not to place the counter too close to driveways, entrances or exits ofmajor centers of commerce such as shopping malls or grocery stores.Under counting may occur due to vehicles stopping on the hose whilewaiting for other vehicles to clear the driveway or entrance.Where parking is allowed next to the curb try not to place the counterwhere vehicles will park on the hoses during the work day. If possibleplace temporary No Parking signs to keep people from parking on thehoses in the count zone.

Use the correct layout and counter for the volume and conditions of thecount zone. The more familiar you are with the capabilities of thecounter, and the purpose of the layout you are using, the better the datacollected will be.Consider safety first. I know it seems like an old clich but, safety is noaccident. Always wear a good quality bright (not old and faded) reflectivevest.Make your presence known to oncoming traffic by placing appropriatesigns an adequate distance before and after the work zone. Your vehicleshould be equipped with flashing lights, such as a rotating beacon orstrobe, use them. Also use the four-way flashers. When conditionswarrant use a spotter. Drivers are often distracted, or unaware of thehazards they pose to workers in the traffic lanes. Watch out for them.Plan out before hand where you will want to park. It may be necessary topost no parking signs in heavily congested downtown areas just to have asafe place to park your vehicle.Schedule the placement of counters to avoid working high volume streetsduring peak hours. Do the side street setups when the arterials andcollectors are busy.Have all of the supplies needed to complete the setup before leaving theshop. I know this sounds silly but not having the right nail or tape cancause a lot of undesirable stress in the field.Wear eye protection when driving PK nails, either safety glasses orgoggles.

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A TimeMark Incorporated Mini-Manual ",Check with your public works and community development departmentsto verify that no construction, or events will interfere with your count.Maintain a positive attitude. Remember, the job you perform is morehazardous than almost any other occupation. Staying alert meansstayi ng al ive.Remember, no one needs a count so badly that safety or risk factorsshould be ignored. OK, enough said. I don't mean to preach, but toomany road workers are getting injured out there, and no one can look outfor you as well as you can.

Selecting the LayoutLayout decisions are directly affected by two main factors: traffic charac-teristics and the type of data desired. Don't make the job any harderthan necessary.First determine what kind of data (Class, Volume, Speed, or Gap) youwant to collect. Then make a best guess as to traffic volume. Becauselayouts have been designed to handle specific traffic patterns and workbest in conditions that match their capabilities always try to match thecounter and layout to the task.The following section will have illustrations of individual road tubelayouts as used by TimeMark Inc. counters. Each layout will be describedin detail as to the type of data that can be collected using it. A layout do'sand don'ts. And how to properly set it out.

Layout Numbers 11,31,2111

~ - .- -- ---

~ .

31 21+ -

~ ?=r le ll

~ = _ _ =I_ -- -- .:=== -.~

~.~:Types of Data:

Raw Data or Volume.Layout 11 is used to collect data in the form of simple axle strikes. Theseare then simply added together into time intervals and multiplied by anAxle Factor to determine volume.

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Road Tube Basics

Layout 31 is used to collect directional data in the form A,B - A(Total strikes on A, (Total Strikes on B Minus Total Strikes on A)).Layout 21 is used to collect directional data on streets divided by amedian strip, and operates the same as a layout 11.

Limitations:Because the upper limit for vehicle detection with these layouts usingTimeMark counters is as high as 800 vehicles per minute, placement onhigh volume roadways is not a concern. This applies to all TimeMarkcounters set to either Raw or Vol ume when used in these configurations.The limitations of these layouts are related to the type of data that maybe extracted by analysis. For basic volume counting they can't be beat.However no classification data may be extracted, and for layout 11 thereis no way to determine volumes by direction.In Raw Data mode it is possible to extract Axle counts, Gaps, and OneTube Speeds.Shadowing caused by vehicles in the near lane (the lane closest to thecounter) may cause a small percentage of the total volume to be lostduring high volume periods, but these losses are usually minimal.

Placement:Tubes may be placed as illustrated, or extended over more or less lanesoftrafficas needed for layouts 11, and 21. Layout 31 may be used inseveral ways to separate directional traffic, or a layout 32 (same as 31only for one way traffic) may be used to separate turning lane volumesfrom through traffic.

Recommendations:Use layout 11 on sites where non-directional vehicle volumes are needed.Use Layout 31 to separate directional traffic volumes and Layout 32 toseparate lane volumes. It is important that the lanes be well divided orseparated for bidirectional studies using layout 31 or negative numbersmay be recorded for vehicles going from B to A.Layout 21 is handy for divided roadways, but can also work anytime adual separated volume is needed such as tracking volumes on an offramp and the adjacent highway at the same time.If an exceptionally long study needs to be conducted (over 2 weeks) onhigh volume roadways use the volume mode of the counter to do thestudy but for normal traffic levels use the Raw Data mode.

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A TimeMark Incorporated Mini-Manual ",Tube Placement:

Keep in mind the basic rules for placing counters near intersectionswhen placing these layouts. It is not necessary to have the tube impactedby both wheels on an axle for the vehicle to be counted. Only the wheelclosest to the counter will be detected. This allows the use of short hosesthat only reach to the middle of the first lane or right turn lane for singlelane counts or to the middle of the far lane for bidirectional studies.Keep in mind that vehicles passing over the hoses in opposite directionssimultaneously may be masked or "shadowed" by the vehicle closest tothe counter and that this tendency increases as more lanes are added tothe study area. On multilane (three or more lanes) conducted on one waystreets with high volumes, try to place the counter on the side of thestreet with the least amount of traffic. If that is impossible considerusing two counters.For Layouts 31,32 the distance between the A hose and the B hoseshould be a from 12 to 14 inches when using a long and a short hose, andshould be 18 to 24 inches when using hoses of equal length.

Layout Numbers 51, 52

51

- ~ .- -- I~ A_::L.C- B

~I'- - - ' 1 1 - _Types of Data:

52

B

Raw Data only. Data collected using these layouts may be analyzed forvehicle count, classification, speed, and gap studies.Limitations:

Use this layout for bidirectional or multi-Iane (up to two lanes) studieswith volumes of 5,000 total vehicles per day (ADT) or less. There is nolimit to the number of vehicles that may be accurately detected for singlelane studies.

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Placement:

Recommendations:

Road Tube Basics

The rules for placement mirror the rules of the previously discussedlayouts. Because the counter uses time stamped events in the analysisprocess, placement of this counter should be in an area where traffic is asfree flowing as possible. Avoid areas where traffic may queue up overthe hoses as this causes strikes to be lost when vehicles are stopped onthe hose.The layout will work equally well with distances from 5 to 20 feet be-tween hoses, but accuracy may be affected by vehicle shadowing duringpeak hour traffic on high volume roads when using shorter spacingbetween hoses. Pick a distance (1like 16 feet) and stick with it for alllayouts using spaced hoses. By staying consistent there won't be anyquestion about what distance you used for a particular study.

A very effective layout on any two lane roadway whether bidirectional orone way. This layout is ideally suited for streets that have poor lanecontrol such as residential streets, narrow streets, or streets that don'thave any lane markings where more than just a simple volume study isneeded.The software uses the time stamped events in the order received (A to B,or B to A) to determine direction. This allows for accurate counts evenwhen vehicles are running down the center of the roadway. Additionallyspeed, classification, and gap may be derived from the same data.In order to assure that the time stamps are recorded properly two criticalfactors need to be addressed. The distance between the hoses, and thelength of the hoses.The pulse travels through the hose at a fixed speed of around 860 MPH.Because the pulse speed is constant, it is possible to determine vehiclespeeds by multiplying the elapsed time between hose strikes by thedistance between the hoses. Using the speed in inches per second thedistance between axles, number ofaxles, and so on may be derived fromthe time stamps produced by the following axles.

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A TimeMark Incorporated Mini-Manual ",Road Tubes Layout (Diagram)

----

4 16' YMeasure 16' from the "A" Itube and make a "V" mark I-- on the roadway.Do this at both ends. ,, 16'A .-_1 BI

~II

The distance between the hoses needs to be a MEASURED distance. Noguess work is allowed here. Place the first hose (the A hose) across theroadway and secure. Using a tape measure and a piece of chalk or keel(Iarge crayon) mark a V, with the tip of the V at the point where the hoseneeds cross. Do this adjacent to the nails on the first hose you put down.Then when the second hose (the B hose) is secured verify that it lines upwith the marks. The overall length of the hoses is important. Start withhoses of equal length and stretch them equally when applying tension.

8'---


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.~.

Layout Number 67, 68

Types of Data:

Limitations:

Placement:

Recommendations:

Road Tube Basics

67

. . . ---- - - -- B e D

ftll

68~+ -_ .-+A B e oft

Raw Data only. Data collected using these layouts may be analyzed forvehicle count, classification, speed, and gap studies.

For roadways with total vehicle volumes exceeding 5,000 per day thelayouts above are ideal but they may be used on lower volumes as well .The advantage of 4 tubes over 2 is related to the shadowing caused byhigh volumes on roadways.

The rules for placement mirror the rules of the previously discussedlayouts. Because the counter uses time stamped events in the analysisprocess, placement of this counter should be in an area where traffic is asfree flowing as possible. Avoid areas where traffic may queue up overthe hoses as this causes strikes to be lost when vehicles are stopped onthe hose.The layout will work equally well with distances from 5 to 20 feet be-tween hoses, but accuracy may be affected by vehicle shadowing duringpeak hour traffic on high volume roads when using shorter spacingbetween hoses. Pick a distance (1 like 16 feet) and stick with it for alllayouts using spaced hoses. By staying consistent there won't be anyquestion about what distance you used for a particular study.

A very effective layout on any two lane roadway whether bidirectional orone way when vehicle volumes exceed 5,000 vehicles per day. This layoutis ideally suited for streets with good lane control and high volumes.

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... ~---~------__------ --------------------------------------

A TimeMark Incorporated Mini-Manual ",The software uses the time stamped events in the order received (A to B,or Oto C) to determine direction and deducts strikes received on A fromthe B total, and likewise for e to D. Speed, classification, and gapstudies may be derived from the same data.In order to assure that the time stamps are recorded properly two criticalfactors need to be addressed. The distance between the hoses, and thelength of the hoses.The pulse travels through the hose at a fixed speed of around 860 MPH.Because the pulse speed is constant, it is possible to determine vehiclespeeds by multiplying the elapsed time between hose strikes by thedistance between the hoses. Using the speed in inches per second thedistance between axles, number ofaxles, and so on may be derived fromthe time stamps produced by the following axles.The distance between the hoses needs to be a MEASURED distance. Noguess work is allowed here.

L a y o u t # 6 7 , # 6 8

Layout 67 and 68 Hose Spacings

Regular Tube Set :(Equal Lengths) 16'10 to 40 MPH = 9"20 to 80 MPH = 18" ~Special Tube Set -,\ ---: ' 1 ~(Long and Short)5 to 40 MPH = 4" 16' I30 to 80 MPH = 6" :A B e o

2 r~

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Road Tube Basics

Place the second hose (that's right, the B hose) across the roadway andsecure it. Using a tape measure and a piece of chalk or keel (Iargecrayon) mark a V, with the tip of the V at the point where the D hoseneeds cross. Do this adjacent to the nails on the first hose you put down.When the second hose (the D hose) is secured, verify that it lines up withthe marks.The A and C hoses are placed in front of the B and D hoses. If the hosesused are short and long, the distance between the A and B (and the Cand D) hose should be 4 inches for vehicle speeds up to 40 MPH, and 6inches for speeds over 40 MPH.If all of the hoses used are the same length, place the A hose 9 inches infront or the B hose (ditto for the C hose in front of the D hose) for speedsup to 40 MPH, or 18 inches if speeds average between 20 and 80 MPH .The overalllength of the hoses is important. Start with hoses of equallength and stretch them equally (

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