CICAS Coordination Meeting
September 28th, September 28th, 20042004
Virginia Update
Research Questions Research Questions Addressed To DateAddressed To Date Is there a difference in brake profiles for Is there a difference in brake profiles for
distracted vs. willful vs. baseline drivers?distracted vs. willful vs. baseline drivers? What’s a too early warning?What’s a too early warning? What’s a too late warning?What’s a too late warning? What timing aspects of the algorithm will What timing aspects of the algorithm will
minimize false alarms and misses? minimize false alarms and misses? What is the effect of warning mode on driver What is the effect of warning mode on driver
response?response? How many detection points are needed to How many detection points are needed to
have an effective algorithm?have an effective algorithm? What functional requirements are known?What functional requirements are known?
Is there a difference in brake Is there a difference in brake profiles for distracted vs. profiles for distracted vs. willful vs. baseline drivers?willful vs. baseline drivers?
0 50 100 150 200 2505
10
15
20
25
30
35
40
Distance from Intersection (ft)
Speed o
f V
ehic
le (
mi/hr)
DistractedWillfulBaseline
Braking ProfilesBraking Profiles
Algorithms can be built based on Algorithms can be built based on detection of violation-likely groups:detection of violation-likely groups:– Drivers stop differently depending on their Drivers stop differently depending on their
intentions and level of distractionintentions and level of distraction Distracted drivers stop harder than othersDistracted drivers stop harder than others Distracted drivers are less likely to stopDistracted drivers are less likely to stop Distracted drivers are more likely to violateDistracted drivers are more likely to violate Willful drivers tend to speedWillful drivers tend to speed
What’s a too early What’s a too early warning?warning? A warning that is issued to a A warning that is issued to a
driver that would have stopped driver that would have stopped without any interventionwithout any intervention– Creates annoyanceCreates annoyance– Decreases user trustDecreases user trust
Too early was determined during Too early was determined during first three intersection studiesfirst three intersection studies
Too Early DistributionToo Early Distribution
• The figure depicts the distance from the intersection at which baseline drivers initiated braking when the signal change occurs at 185’
• An algorithm that initiates a warning prior to reaching 135’ would create false alarms
Nu
mb
er
of
Dri
ve
rs (
ou
t o
f 2
8)
Distance to Intersection (ft)
What’s a too late What’s a too late warning?warning? A warning that is issued to a A warning that is issued to a
driver that would benefit, but with driver that would benefit, but with timing such that insufficient timing such that insufficient distance remains for the driver to distance remains for the driver to perceive, react, and stop prior to perceive, react, and stop prior to entering the intersection.entering the intersection.– Decreases safety benefit of systemDecreases safety benefit of system– Decreases user trustDecreases user trust
Inneffective Warning Timing (Too Late)
Pro
babili
ty
Warning Region
0 ft 250 ft
Annoyance Warning (Too Early)
Pro
babi
lity
Inneffective Warning Timing (Too Late)
Pro
babili
ty
Warning Region
0 ft 250 ft
Annoyance Warning (Too Early)
Pro
babi
lity
Ideal Case – Classification Ideal Case – Classification ClearanceClearance
Real Case – Classification InterferenceReal Case – Classification Interference
Annoyance Alarm (Too Early)
Nor
mal
Pro
babi
lity
Warning Region
0 ft 250 ft
Ineffective Warning Timing (Too Late)
Pro
babili
ty
Maximizing Curve SeparationMaximizing Curve Separation(Methods to Minimize Misses and False (Methods to Minimize Misses and False Alarms)Alarms)
Take advantage of the “all red” phase Take advantage of the “all red” phase and the time it takes for opposing and the time it takes for opposing vehicles to get into the collision zone to vehicles to get into the collision zone to allow vehicles to pass through without allow vehicles to pass through without warning (time)warning (time)
Take advantage of the intersection’s Take advantage of the intersection’s buffer zone, the area beyond the stop buffer zone, the area beyond the stop bar but prior to significant collision risk bar but prior to significant collision risk (space)(space)
Design warnings that minimize reaction Design warnings that minimize reaction time and maximize deceleration by time and maximize deceleration by conveying necessary urgencyconveying necessary urgency
“Normal” Brake Initiation
Normal ApproachNormal ApproachNo Warning or Timely WarningNo Warning or Timely Warning
Too Late WarningToo Late Warning
Algorithm Trip
Reaction Time“Normal” Brake Initiation
Allowing the ViolationAllowing the ViolationPreventing the CrashPreventing the Crash
Making Use of Pre-Collision Zones Making Use of Pre-Collision Zones of the Intersectionof the Intersection
Compliant
Zone
Violation Zone
Intrusion Zone
Collision Zone
Warning Activation
Preventing the CollisionPreventing the Collision
Maximize Warning Maximize Warning EffectivenessEffectiveness
DII/DVI research to date has DII/DVI research to date has demonstrated the importance of demonstrated the importance of countermeasure design.countermeasure design.– Prototype warnings were evaluated for Prototype warnings were evaluated for
Urgency, Distinguishability, and Urgency, Distinguishability, and Appropriateness in the labAppropriateness in the lab
Evaluators preferred icon auditory warnings Evaluators preferred icon auditory warnings over descriptive (i.e. buzzer vs. “Stop”)over descriptive (i.e. buzzer vs. “Stop”)
However, experimentation showed However, experimentation showed clear advantages for the word “Stop”clear advantages for the word “Stop”
Maximize Warning Maximize Warning EffectivenessEffectiveness
0
10
20
30
40
50
60
0 50 100 150 200 250
Distance from Intersection (ft)
Sp
eed
(ft
/sec
)
"Stop" CAMP Warning
Comparison of Comparison of Auditory Alerts Auditory Alerts
GroupPercent Who Stop Before
Collision Zone
Avg. Maximum Deceleration (g)
Avg. Reaction Time (sec)
CAMP Warning
64% -0.64 0.88
“Stop” 81% -0.73 1.07
Effectiveness of Visual Effectiveness of Visual DisplayDisplay
– High Heads-Down Visual DVI was High Heads-Down Visual DVI was ineffectiveineffective The display was perceived by less than The display was perceived by less than
5 percent of the participants5 percent of the participants Evaluation of DVIs is now focused on Evaluation of DVIs is now focused on
auditory and haptic warning modesauditory and haptic warning modes
How many detection points How many detection points are needed to have an are needed to have an effective algorithm?effective algorithm? Single-Point detection of speed does not Single-Point detection of speed does not
result in reliable warning decisionsresult in reliable warning decisions– Improved reliability would consistently result Improved reliability would consistently result
in too late warningsin too late warnings
Continuous detection is the most Continuous detection is the most adaptive to any algorithm type and adaptive to any algorithm type and produces the best theoretical produces the best theoretical performanceperformance
Multi-point alternatives are being testedMulti-point alternatives are being tested
Simulation of Single Simulation of Single Point vs. Continuous Point vs. Continuous DetectionDetectionMissed ViolationsMissed Violations
0 50 100 150 200 250 300 3500
10
20
30
40
50
60
70
Range (feet)
Spe
ed (
mph
)
0 50 100 150 200 250 300 3500
10
20
30
40
50
60
70
Range (feet)
Spe
ed (
mph
)
Speed determined at given distance from intersection Speed determined at given distance from intersection for violations that occurredfor violations that occurred
Single point detection would not have worked for most Single point detection would not have worked for most of the drivers who violatedof the drivers who violated
With continuous detection, three violating drivers With continuous detection, three violating drivers would not have been detected; however, none of would not have been detected; however, none of these drivers would have been in the crash zone.these drivers would have been in the crash zone.
What functional requirements What functional requirements are known?are known?
Detuning tests run to dateDetuning tests run to date– SensorsSensors
AccelerationAcceleration VelocityVelocity
– PositioningPositioning Lateral PositionLateral Position Longitudinal PositionLongitudinal Position
0.00.10.20.30.40.50.60.70.80.91.0
Velocity Detuning Level
No
rma
lize
d M
ea
n
Re
qu
ire
d D
ec
ele
rati
on
(g
)
Sensor: VelocitySensor: VelocityNormalized Deceleration: At DVI onset, the Normalized Deceleration: At DVI onset, the average deceleration in g’s that would be required average deceleration in g’s that would be required to stop by the stop barto stop by the stop bar
Sensor: VelocitySensor: VelocityNormalized Deceleration: At DVI onset, the Normalized Deceleration: At DVI onset, the average deceleration in g’s that would be required average deceleration in g’s that would be required to stop by the stop barto stop by the stop bar
0.00.10.20.30.40.50.60.70.80.91.0
Velocity Detuning Level
No
rma
lize
d M
ea
n
Re
qu
ire
d D
ec
ele
rati
on
(g
)
25mph
70mph
Sensor: AccelerometerSensor: AccelerometerNormalized Deceleration: At DVI onset, the Normalized Deceleration: At DVI onset, the average deceleration in g’s that would be required average deceleration in g’s that would be required to stop by the stop barto stop by the stop bar
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
-0.05g -0.025g 0.0g 0.025g 0.05g
Acceleration Detuning Level
No
rmalized
Mean
Req
uir
ed
Decele
rati
on
(g
)
Positioning: LateralPositioning: LateralNormalized Deceleration: At DVI onset, the Normalized Deceleration: At DVI onset, the average deceleration in g’s that would be required average deceleration in g’s that would be required to stop by the stop barto stop by the stop bar
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
-5 m -2.5 m -1 m 0 m 1 m 2.5 m 5 m
Lateral Positioning Detuning Level
No
rmalized
Mean
Req
uir
ed
Decele
rati
on
(g
)
25mph
70mph
D = 125 ft
d = 125.6 ft
Positioning: LateralPositioning: Lateral
Assumes a 12 foot lane widthAssumes a 12 foot lane width Would also apply to curved road Would also apply to curved road
geometrygeometry
Positioning: LateralPositioning: LateralLane Position: Correct vs. IncorrectLane Position: Correct vs. Incorrect
25 mph Correct
25 mph Incorrect
70 mph Correct
70 mph Incorrect
-5 m 0 6 0 6
-2.5 m 0 6 3 3
-1 m 6 0 6 0
0 m 6 0 6 0
1 m 6 0 6 0
2.5 m 0 6 1 5
5 m 0 6 0 6
Positioning: LongitudinalPositioning: LongitudinalNormalized Deceleration: At DVI onset, the Normalized Deceleration: At DVI onset, the average deceleration in g’s that would be required average deceleration in g’s that would be required to stop by the stop barto stop by the stop bar
0.0
0.4
0.8
1.2
1.6
2.0
-15 m -10 m -5 m -3.5 m -2 m -1 m 0 m 1 m 2 m 3.5 m 5 m 10 m 15 m
Longitudinal Positioning Detuning Level
No
rmal
ized
Mea
n
Req
uir
ed D
ecel
erat
ion
(g)
25 mph
70 mph
Positioning: LongitudinalPositioning: LongitudinalNormalized Deceleration: At DVI onset, the Normalized Deceleration: At DVI onset, the average deceleration in g’s that would be required average deceleration in g’s that would be required to stop by the stop barto stop by the stop bar
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
-5 m -3.5 m -2 m -1 m 0 m 1 m 2 m 3.5 m 5 m
Longitudinal Position Detuning Error
No
rma
lize
d M
ea
n
Re
qu
ire
d D
ec
ele
rati
on
(g
)
25 mph
70 mph
Project PlansProject Plans
Completing studies to answer the following Completing studies to answer the following questionsquestions– What is the optimal timing for collision warning?What is the optimal timing for collision warning?– What is the optimized braking profile for a haptic What is the optimized braking profile for a haptic
warning system?warning system?– What are the remaining functional requirements What are the remaining functional requirements
and specifications of an ICA system?and specifications of an ICA system?– What DII and DVI will result in optimal driver What DII and DVI will result in optimal driver
response?response?– What technologies show the most promise for the What technologies show the most promise for the
feasible architectures?feasible architectures?– What ICA architectures are feasible for meeting the What ICA architectures are feasible for meeting the
requirements and specifications?requirements and specifications?
What is the optimal What is the optimal timing for collision timing for collision warning?warning? Need to continue to systematically Need to continue to systematically
determine the ‘too late’ points for determine the ‘too late’ points for various DIIs and DVIsvarious DIIs and DVIs– A goal of zero misses is being usedA goal of zero misses is being used– Driver acceptance is being consideredDriver acceptance is being considered
‘‘Too late’ thresholds are being Too late’ thresholds are being contrasted with known ‘too early’ contrasted with known ‘too early’ thresholds, to determine the potential thresholds, to determine the potential for nuisance alarmsfor nuisance alarms
What is the optimized What is the optimized braking profile for a haptic braking profile for a haptic warning system?warning system?
It is known that severely distracted drivers It is known that severely distracted drivers can have perception reaction times as long can have perception reaction times as long as 4 sec, which would make any traditional as 4 sec, which would make any traditional warning ineffectivewarning ineffective
A brake assist or full brake system is seen as A brake assist or full brake system is seen as a possible means of aiding these drivers, a possible means of aiding these drivers, since reaction time is eliminatedsince reaction time is eliminated
Three issues are being resolved:Three issues are being resolved:– When should the system be activated?When should the system be activated?– How long should the system remain active?How long should the system remain active?– How much braking authority should be used?How much braking authority should be used?
Brake Assist ExampleBrake Assist Example
Braking Profiles, 35 mph Example
0.0
0.2
0.4
0.6
0.8
0 1 2 3 4 5 6
Time from Warning Initiation, secs
Dec
eler
atio
n,
g's
Driver braking at 0.4 g from 1.5 s
Assisted Braking, Ease-On at 1 s, rise to 0.65 g after 0.5 s
Savings of 50ft at Savings of 50ft at 35mph35mph
Effect of Assisted Braking
0
100
200
300
400
500
0 10 20 30 40 50 60
Initial Vehicle Speed, mph
To
tal
Sto
pp
ing
Dis
tan
ce
, ft
Typical Brake to Warning: RT=1.5 s, decel=0.4 g
Assisted Braking Case: On at 1.0 s, decel rises to 0.7 g in 0.5 s
What are the remaining What are the remaining functional requirements and functional requirements and specifications of an ICA specifications of an ICA system?system? Need to test between 1 m and 2.5 Need to test between 1 m and 2.5
m on lateral position.m on lateral position. Need to determine effects of Need to determine effects of
various communication system various communication system update ratesupdate rates
What DII and DVI will What DII and DVI will result in optimal driver result in optimal driver response?response? Will continue to conduct Will continue to conduct
evaluation of brake assist and full evaluation of brake assist and full brake options.brake options.
Will continue to test auditory and Will continue to test auditory and haptic options.haptic options.
What technologies show the What technologies show the most promise for the feasible most promise for the feasible architectures?architectures?
VTTI will continue to determine VTTI will continue to determine technologies that meet the minimal technologies that meet the minimal functional requirementsfunctional requirements– ControllerController– PositioningPositioning– SensorsSensors– Driver InterfaceDriver Interface– CommunicationsCommunications– Computations Computations
Controller Controller TechnologiesTechnologies No single interface standard availableNo single interface standard available Available timing information not accurate Available timing information not accurate
enoughenough– Ex.: Eagle controllers report timings to whole Ex.: Eagle controllers report timings to whole
secondsseconds Overhead from 10Hz polling may overload Overhead from 10Hz polling may overload
controllercontroller May need to mandate standards for data May need to mandate standards for data
format/availabilityformat/availability New Advanced Traffic Controllers (ATCs) may New Advanced Traffic Controllers (ATCs) may
address some of these issuesaddress some of these issues
Positioning Positioning TechnologiesTechnologies Infrastructure basedInfrastructure based
– Radar: costly to cover all lanesRadar: costly to cover all lanes– RFID: may require multiple readers per RFID: may require multiple readers per
approachapproach Vehicle basedVehicle based
– GPS with INS: high cost to get high GPS with INS: high cost to get high accuracy and update rateaccuracy and update rate
– RFID in conjunction with odometer: high RFID in conjunction with odometer: high accuracy at one distance, then decrement accuracy at one distance, then decrement remaining distance using odometerremaining distance using odometer
Sensor TechnologiesSensor Technologies
InfrastructureInfrastructure– Radar: velocity and decelerationRadar: velocity and deceleration
Vehicle velocityVehicle velocity– GPS with INS: velocityGPS with INS: velocity– Velocity from vehicle networkVelocity from vehicle network
Vehicle decelerationVehicle deceleration– Accelerometer to sense brakingAccelerometer to sense braking– Mechanical sensor on brake pedalMechanical sensor on brake pedal
Driver Interface Driver Interface TechnologiesTechnologies
InfrastructureInfrastructure– StrobesStrobes– VMS signVMS sign– Intelligent rumble stripsIntelligent rumble strips
VehicleVehicle– Auditory: tones or voice warningAuditory: tones or voice warning– Haptic: Soft braking (pulses), seat Haptic: Soft braking (pulses), seat
shaker, brake assist, or full brakingshaker, brake assist, or full braking
Communications Communications TechnologiesTechnologies Must be generic to support multiple Must be generic to support multiple
interfacesinterfaces Bi-directional link depending on Bi-directional link depending on
architecturearchitecture DSRC current best choiceDSRC current best choice
– Not yet available off-the-shelfNot yet available off-the-shelf– Security issuesSecurity issues– Styling issuesStyling issues– Currently simulating with 802.11a hardware Currently simulating with 802.11a hardware
and softwareand software
Computations Computations TechnologiesTechnologies
InfrastructureInfrastructure– On board signal controllerOn board signal controller– Custom DSP or hybrid microcontrollerCustom DSP or hybrid microcontroller
Must talk to infrastructure components Must talk to infrastructure components – radarradar– RFID RFID – DSRC DSRC – DIIDII
Easily modified to allow algorithm Easily modified to allow algorithm changeschanges
Computations Computations TechnologiesTechnologies VehicleVehicle
– Custom DSP or hybrid microcontrollerCustom DSP or hybrid microcontroller Must talk to all necessary data sourcesMust talk to all necessary data sources
– vehicle networkvehicle network– DSRCDSRC– GPS w/INSGPS w/INS– RFIDRFID– DVIDVI
Easily modified to allow algorithm changesEasily modified to allow algorithm changes
What ICA architectures are What ICA architectures are feasible for meeting the feasible for meeting the requirements and requirements and specifications?specifications? VTTI will continue to evaluate the VTTI will continue to evaluate the
available technologies as suitable to available technologies as suitable to several architecturesseveral architectures– Infrastructure onlyInfrastructure only– Mostly infrastructure based with receiver Mostly infrastructure based with receiver
and DVI in vehicleand DVI in vehicle– Mostly vehicle based with transmitter in Mostly vehicle based with transmitter in
infrastructure (provides stop bar location infrastructure (provides stop bar location and signal phase/timing)and signal phase/timing)
– Totally vehicle based with map in vehicleTotally vehicle based with map in vehicle For stop signed intersectionsFor stop signed intersections
Architecture Example 1. RFID tag reader and in-vehicle warning
RFID transmits distance to
intersection to vehicle
Odometer updates distance
to intersection
DVI in vehicle presents warning and driver stops
DSRC transmits signal phase and timing to vehicle
Radar determines vehicle speed and
distance
Architecture Example 2. Infrastructure radar and DII
Radar determines vehicle speed and
distance
Algorithm calculates violation
DII in infrastructure
presents warning and driver stops
DSRC violation warning also transmitted to properly
equipped vehicles
Architecture Example 3. In-vehicle positioning system and in-vehicle warning
In-vehicle map query for stop bar
location
Distance and speed calculated
to check for violation
DVI in vehicle presents warning and driver stops
STOP
STOP STOP
STOP
Additional Pre-FOT Additional Pre-FOT TestingTesting Next steps toward an FOTNext steps toward an FOT
– Passive evaluation of both Passive evaluation of both infrastructure based and cooperative infrastructure based and cooperative ICA systemsICA systems When was the warning issued?When was the warning issued? How many false alarms and misses How many false alarms and misses
occurred?occurred? What would have been the resulting What would have been the resulting
driver and traffic consequences?driver and traffic consequences?
Additional Pre-FOT Additional Pre-FOT TestingTesting Data from the passive evaluation will Data from the passive evaluation will
also validate the functional also validate the functional specifications for a cooperative systemspecifications for a cooperative system
Then we will have enough data to Then we will have enough data to activate the DII warning at a limited activate the DII warning at a limited number of intersections and continue number of intersections and continue to closely monitor trafficto closely monitor traffic– Do naturalistic on-road experimentation Do naturalistic on-road experimentation
for the cooperative system with for the cooperative system with instrumented vehicleinstrumented vehicle
Look for unintended consequencesLook for unintended consequences Make the final assessment of acceptabilityMake the final assessment of acceptability