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Group 3Mohhammad Afsar Sujon
Traffic Speed Studies
2
Types of Speed Studies
July 22, 2012 Traffic Speed Studies
Spot Speed Studies spot speed studies
to measure speeds at specific locations
#
studies speeds at specific locations #determine the design speed
# aid in conducting safety studies #analyze
special operational situations
Travel Time Studies Travel time
is the time taken by a vehicle to cross a given segment of a street or
highway
#evaluate the effectiveness of traffic improvements
#provide economic analyses of alternatives
#evaluate trends in
efficiency and level of service
Speed Delay Studies Delay is the
time lost by a vehicle due to causes beyond the control of the driver
#identify problem areas #determine the efficiency of a route
#evaluate effectiveness of traffic improvements # provide economic analyses of
alternatives
Specific Objectives of Traffic Speed StudyDetermine Vehicle Spot Speed
During Survey Period
Plot Histogram, Frequency Curve & Cumulative
Frequency Curve
Determine Weighted Average Speed, Pace, modal Speed, speed Limit, design
Speed
Determine Time Mean Speed(Vt) & Space Mean
Speed(Vs),and Proof Vs < Vt
Proof The Wardrop Relationship Between Time
Mean Speed(Vt) & Space Mean Speed(Vs),
Find Delay Time & Cost Of Delay
Draw Speed –Flow Curve
Scope of Traffic Speed Studies
Establishing the
effectiveness of new or existing
speed limits
Magnitudes, classifications and the time and
directional split of
vehicular flows.
Time and directional
split of vehicle is useful to
identify tidal flow.
Determining appropriate speed limits
for application
Investigation of high-accident
locations at which speed is suspected
to be a contributing cause to the
accident experience.
Specific control for
the timing of “yellow” and
“all red” intervals for
traffic signals,
placement of signs,
and development
of signal progressions.
Footer text here5
Speed Determining Methods
July 22, 2012
STOPWATCH METHOD
RADAR METER METHOD
PNEUMATIC ROAD TUBE METHOD
For the unavailability of Radar & Pneumatic Road Tube method we had to use Stopwatch.
Footer text here6
Survey Area
July 22, 2012
Panthapath-Green road intersection and Panthapath-Mirpur Road intersection
Spot speed
Average speed of individual group from Panthopath to Russel-
square(mph)
Group 1 Group 2 Group 3 Average directional
speed (mph)
18.43 16.38 19.48 18.10
Average speed of individual group from
Russel-square to Panthopath(mph)
Group 4 Group 5 Group 6 Average directional
speed (mph)
20.33 20.00 16.92 19.08
Footer text here8
Histograms of vehicles
July 22, 2012
15 20 10 5 25 30 40 35
0102030405060
( Panthopath to Russel-square )
Bin
Freq
uenc
y
15 20 25 10 30 5 35 40 More
0
10
20
30
40
( Russel-square to Panthopath )
BinFr
eque
ncy
Footer text here9
Frequency distribution curve
0 5 10 15 20 25 30 35 40 45 50 55 60 65 7005
10152025
(Panthopath To Russel Square)
% Frequencies
July 22, 2012
0 5 10 15 20 25 30 35 40 45 50 55 60 65 700102030 (Russel Square To Panthopath)
Footer text here10
Cumulative frequency distribution curve
July 22, 2012
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70020406080
100 (Panthopath to Russel-square)
Cumulative% Frequencies
0 5 10 15 20 25 30 35 40 45 50 55 60 65 700255075
100(Russel-square to Panthopath)
TRAFFIC SPEED STUDIES11
Tabular data analysis Data obtained from Group 1, 2, 3 (Panthopath to Russel-square)
Speed groups (mph)
Mean of speed
group, v (mph)
Frequency, f
% frequency
Cumulative frequency f x v (v-ū)² f x (v-ū)²
0-4 2.00 0.00 0.00 0.00 0 236.97 0.004-8 6.00 5.00 5.05 5.05 30 129.82 649.11
8-12 10.00 15.00 15.15 20.20 150 54.67 820.0612-16 14.00 22.00 22.22 42.42 308 11.52 253.4116-20 18.00 23.00 23.23 65.66 414 0.37 8.4520-24 22.00 23.00 23.23 88.89 506 21.22 487.9624-28 26.00 6.00 6.06 94.95 156 74.06 444.3928-32 30.00 3.00 3.03 97.98 90 158.91 476.7432-36 34.00 2.00 2.02 100.00 68 275.76 551.5236-40 38.00 0.00 0.00 100.00 0 424.61 0.00
∑ 99.00 1722 1387.92 3691.64
ū=∑f x v/ ∑f 17.39
July 22, 2012
Footer text here12
Tabular data analysis Data obtained from Group 4, 5, 6 (Russel-square to Panthopath)
Speed groups (mph)
Mean of speed
group, v (mph)
Frequency, f
% frequency
Cumulative frequency f x v (v-ū)² f x (v-ū)²
0-4 2.00 0.00 0.00 0.00 0 300.81 0.004-8 6.00 3.00 3.03 3.03 18 178.06 534.17
8-12 10.00 8.00 8.08 11.11 80 87.31 698.4512-16 14.00 16.00 16.16 27.27 224 28.56 456.8916-20 18.00 42.00 42.42 69.70 756 1.81 75.8420-24 22.00 41.00 41.41 111.11 902 7.06 289.2824-28 26.00 11.00 11.11 122.22 286 44.31 487.3628-32 30.00 7.00 7.07 129.29 210 113.56 794.8932-36 34.00 0.00 0.00 129.29 0 214.81 0.00
∑ 128.00 2476 976.25 3336.88ū=∑f x v/ ∑f 19.34
July 22, 2012
Footer text here13
% Frequencies
July 22, 2012
0 5 10 15 20 25 30 35 40 45 50 55 60 65 700
5
10
15
20
25
% Frequencies
Modal speed= 23 Kmph
pace= 20~35 Kmph
Figure-: Pace & modal speed (Panthopath to Russel-aquare )
Footer text here14
Cumulative% Frequencies
July 22, 2012
0 5 10 15 20 25 30 35 40 45 50 55 60 65 700102030405060708090
100
Cumulative% Frequencies
98th percentile= 47 kmph
85th percentile= 35kmph
15th percentile= 16kmph
Figure-: Determination of Speed limit, design speed (Panthopath to Russel-square )
Footer text here15
Relationship between Space Mean Speed and Time Mean Speed
Speed Group (Mph)
Mean Speed of Group, V
(Mph)
No. of vehicles
in group, f
f*V f/V f(V-Vs)²
0-5 2.50 0 0.00 0.00 0.005-10 7.50 4 30.00 0.53 146.89
10-15 12.50 39 487.50 3.12 43.8215-20 17.50 14 245.00 0.80 217.3320-25 22.50 6 135.00 0.27 479.5425-30 27.50 2 55.00 0.07 388.6530-35 32.50 0 0.00 0.00 0.00Total 65 952.50 4.79 1276.23
July 22, 2012
Panthopath To Russel Square Russel square to Panthopath
Speed Group (Mph)
Mean Speed
ofGroup, V (Mph)
No. of vehicles in group,
f
f*V f/V f(V-Vs)²
0-5 2.5 9 22.5 3.60496.8
4
5-10 7.5 18 135 2.40106.2
9
10-15 12.5 16 200 1.28105.6
8
15-20 17.5 24 420 1.371375.
3220-25 22.5 0 0 0.00 0.0025-30 27.5 0 0 0.00 0.0030-35 32.5 0 0 0.00 0.00
35-40 37.5 2 75 0.051520.
21
Total 69 852.5 8.703604.
34
Time mean speed, Vt = ∑f*V / ∑f
= 952.50/65 = 14.65 mph Space Mean Speed, Vs = ∑f/∑(f/V)
= 65/4.79 = 13.57 mph So, for this direction Vs < Vt
Time mean speed, Vt = ∑f*V / ∑f = 852.5/69 = 12.35 mphSpace Mean Speed, Vs = ∑f/∑(f/V) = 69/8.70 = 7.93 mphSo, for this direction Vs < Vt
So,Vs < Vt
Footer text here16
The Wardrop Relationship Between Time Mean Speed And The Space Mean Speed
July 22, 2012
# Time mean speed, Vt = ∑f*V / ∑f =
852.5/69 = 12.35 mph# Space Mean Speed, Vs = ∑f/∑(f/V) = 69/8.70 = 7.93 mph# Variance, Sd² = ∑f(V-Vs)²/(∑f-1) = 3604.34/ 68 = 53 mph# Vs + Sd²/Vs = 7.93 + 53/7.93
= 14.61 > (Vt = 12.35 )
Russel-square- Panthopath Direction
# Time mean speed, Vt = ∑f*V / ∑f = 952.50/65 = 14.65 mph # Space Mean Speed, Vs = ∑f/∑(f/V) = 65/4.79 = 13.57 mph # Variance, Sd² = ∑f(V-Vs)²/(∑f-1) = 1276.23/ 64 = 19.94mph# Vs + Sd²/Vs = 13.57 + 19.94/13.57 = 15.04 >( Vt =14.65 )
Panthopath- Russel-square Direction
The Wardrop Relationship (Vs + Sd²/Vs > Vt ) Between Time Mean Speed And The Space Mean Speed Which Has Been Found Right.
Footer text here17
Delay StudyPanthopath- Russell Square
Car 3- wheeler Bus Motorcycle
Free flow Speed(mph) 20.00 15.00 18.00 25.00Average Speed(mph) 15.51 12.21 12.53 16.49
Delay from Free Flow Speed(mph) 4.49 2.79 5.47 8.51Delay (hr/km) 0.14 0.22 0.11 0.07
Russell Square- Panthopath
Car 3- wheeler Bus Motorcycle
Free flow Speed(mph) 20.00 15.00 18.00 25.00Average Speed(mph) 11.78 10.71 11.63 13.05
Delay from Free Flow Speed(mph) 8.22 4.29 6.37 11.95Delay (hr/km) 0.08 0.14 0.10 0.05
July 22, 2012
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Value of Travel Time (VOT) and Vehicle Operating Cost (VOC)
Vehicle Type Bus Car 3- wheeler MotorcycleFin Eco Fin Eco Fin Eco Fin Eco
1 hour delay cost (assuming quarter liter Diesel fuel + 1/15 liter of lubricant consumed)
395.92 311.48 162.98 138.35 155.67 128.53 154.57 122.43
1 hour delay cost (assuming quarter liter Petrol fuel + 1/15 liter of lubricant consumed)
393.47 302.48 183.48 149.65 162.17 137.53 162.19 129.53
July 22, 2012
Hourly VOC for 2012/13
Item Cost Unit Bus Car 3- wheeler Motor CycleUnit Costs Fin Econ Fin Econ Fin Econ Fin Econ
Purchase cost of vehicle
Tk'000 per vehicle 4456 3815 2292 1399 327 195 137 195
Cost of new tire Tk per tire 25375 17780 4163 2932 1863 1309 1181 1309Maintenance labor
cost Tk per hour 92 86 82 66 82 66 82 66
Overhead cost Tk '000 per annum 1898 1468 48 39 19 23 19 23
Crew cost Tk per hour 50 40 33 28 26 22 26 22Fuel cost Diesel Tk per liter 61 58 65 43 46 38 46 38Fuel cost petrol Tk per liter 85 72 76 62 76 62 76 62Lubricant cost Tk per liter 270 198 230 184 230 184.00 230 184
Estimated factor for VOC calculation 2012/13
Footer text here19
Value of Travel Time (VOT) and Vehicle Operating Cost (VOC)
Vehicle Type Bus Car 3- wheeler Motorcycle Fin Eco Fin Eco Fin Eco Fin Eco
Diesel million Tk. 2.4 1.9 1.0 0.8 1.5 1.2 0.5 0.4
Petrol million Tk. 2.4 1.8 1.1 0.9 1.6 1.3 0.5 0.4
July 22, 2012
VOC calculation table
Vehicle Bus Car 3- wheeler MotorcycleAverage
Occupancy 40 4 4 1.1VOT
(Tk/passenger/hr) 40.7 78.8 33 58.4Total yearly delay
(hr) 642 1051 642.5 350.5Total VOT (million
Tk.) 1.1 0.33 0.08 0.02
Travel Time Cost of Passengers by Category of Vehicle
Footer text here20
Speed flow curve
Group No.
Flow (PCU/hr)
Speed (mile/hr)
Capacity (PCU/hr)
V/C ratio
1 905 16.21
4587
0.197297
2 917 12.39 0.199913
3 972 16.09 0.211903
July 22, 2012
Panthapath To Russell Square (E To W)
900 910 920 930 940 950 960 970 98005
101520
Panthapath to russell square
Speed (mile/hr)
Group No.
Flow (PCU/hr)
Speed (mile/hr)
Capacity (PCU/hr) V/C ratio
4 778 11.763807
0.204360.24402
45 929 13.990.24875
26 947 11.6
RUSSELL SQUARE TO PANTHAPATH (W to E)
7607808008208408608809009209409600
5
10
15Russell square to panthapath
Footer text here21
RecommendationsAutomatic data collection process must be used for
more realistic information.
Manual count method must be done by trained
enumerators.
Huge amount of data should be collected for
data combination between different
group. The result of the study
suggests that traffic control system have to
improve for smooth flow.
Volume study must be done before speed
study.
Speed & delay studies must be done carefully
for cost & benefit calculation of a project.
July 22, 2012
Footer text here22
Scope for Further Study
July 22, 2012
This speed study was completed by un-
skilled enumerators that leads to some
error in data collection process.
Data collected by manual method is
unreliable and irreversible. For more representatives and
reliable data automatic data collection method
should be followed.
Data were collected for short-period (30
minute) can’t implies flow characteristics of
the road. If 3days continuous data were collected, that would
be much more representative and
realistic.