comparison of pcu for indian and american conditions

Comparison of Passenger Car Equivalent (Passenger Car Unit)

on Urban Arterial Roads between India (Chennai & Mumbai)

and U.S. (Lincoln, NE)

Jianan Zhou (UNL), Noorul Sharik (IITM) ,

Priyanka (IITM), Raghupathi Kandiboina (IITB)

April 25, 2016

Content

Introduction

Methodology for PCE determination

Data Collection

PCE Calculation

Comparison Analysis

Conclusion

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2

3

4

5

6

1. IntroductionDefinition of Passenger Car Equivalent (Passenger Car Unit)

• A Passenger Car Equivalent is essentially the impact that a mode of

transport has on traffic variables (such as headway, speed, density)

compared to a single car.

• PCE plays a crucial role in capacity analysis.

• In U.S., the term “PCE” is used, while in India, the term “Passenger Car

Units” (PCU) is used instead of “PCE”.

1. IntroductionResearch Objective

• Focus on PCE of trucks (for India: HCV; for U.S.: single + heavy truck)

• Compare PCEs at midway on urban arterial roads between India (Chennai)

and U.S. (Lincoln, NE)

• Compare PCEs at intersections on urban arterial roads between India

(Mumbai) and U.S. (Lincoln, NE)

• Give recommended PCE value for midway and intersection on urban arterial

roads in India and U.S.

1. IntroductionResearch Procedure and Task

• Task 1: Literature review for different PCE determination method

- after that, we find using headway, delay and speed-area

method to calculate PCE in this research

• Task 2: Data collection

• Task 3: PCE calculation

- Headway and speed-area method for PCE at midway

- Delay and speed-area method for PCE at intersection

Research Procedure and Task

• Task 4: Statistical analysis for PCE comparison

- Midway during off-peak/peak hour between U.S. and India

- Intersection during off-peak/peak hour between U.S. and India

- Midway during all time between U.S. and India

- Intersection during all time between U.S. and India

1. Introduction

• Task 5: Discussion and draw conclusion

Content

Introduction


Data Collection

PCE Calculation

Comparison Analysis

Conclusion

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3

4

5

6

Headway-based Methodology

2. Methodology for PCE Determination

𝐻 − 𝑃𝐶𝐸 = 1 − 𝑝) ℎ

𝑝𝑡+ ℎ𝑡𝑝 − ℎ𝑝𝑝) + 𝑝 ∗ ℎ𝑡𝑡

ℎ𝑝𝑝≈

ℎ𝑡.

ℎ𝑝.where:

𝑝= percentage of trucks at a mixed traffic stream;

ℎ𝑝𝑡 = Mean headway in seconds for passenger cars following trucks;

ℎ𝑡𝑝 = Mean headway in seconds for trucks following passenger cars ;

ℎ𝑝𝑝= Mean headway in seconds for passenger cars following passenger cars ;

ℎ𝑡𝑡 = Mean headway in seconds for trucks following trucks;

ℎ𝑝. = Mean headway in seconds for passenger cars following passenger cars or trucks;

ℎ𝑡. = Mean headway in seconds for trucks following passenger cars or trucks.

*This method was proposed by Krammes in 1986. Until now, it has been used in PCE determination

at highway and freeway in U.S., but has not been used in India. Theoretically, this method performs

well for conditions that vehicles strictly following lane disciplines.

Delay-based Methodology


where:

∆𝑑𝑡= additional delay caused by per truck

𝑑0= average delay per vehicle of passenger car when truck percentage is 0%(base delay)

𝑛𝑡= number of truck in mixed queue in one cycle

𝑗= position of vehicle in mixed queue in one cycle

𝑝,𝑚= position of first truck and last vehicle in mixed queue in one cycle

𝑇𝑇𝑗𝑡 ,𝑇𝑇𝑗

0 = travel time for jth vehicle in mixed queue and in all passenger cars queue

𝐷 − 𝑃𝐶𝐸 = 1 +∆𝑑𝑡

𝑑0= 1 +

𝑗=𝑝𝑚 𝑇𝑇𝑗

𝑡 − 𝑇𝑇𝑗0

𝑛𝑡𝑑0

*This method was proposed by Zhao in 1996. Until now, it has been used in PCE determination at

intersection in U.S., but has not been used in India. Theoretically, this method performs well for

conditions that vehicles strictly following lane disciplines and high speed difference between trucks

and passenger cars.

Speed-area Methodology


𝑆𝐴 − 𝑃𝐶𝐸 𝑆𝐴 − 𝑃𝐶𝑈) = 𝑉𝑐 𝑉𝑡

𝐴𝑐 𝐴𝑡

where:

𝑉𝑐 = Mean speed for passenger cars

𝑉𝑡 = Mean speed for trucks

𝐴𝑐 = Projected rectangular areas (length*width) on the road for passenger cars

𝐴𝑡 = Projected rectangular areas (length*width) on the road for trucks

*This method was proposed by Chandra in 2000. Until now, it has been used in PCE determination

at highway and intersection in India, but has not been used in U.S. Theoretically, this method

performs well for conditions that vehicles do not following lane disciplines.

Summary for Methodology


Headway Method → H-PCE at midway for India and U.S.

Delay Method → D-PCE at intersection for India and U.S.

Speed-area Method → SA-PCE at midway and intersection

for India and U.S.

Longitudinal Effects

(effects on followers)

Lateral Effects

(effects on adjacent

vehicles)

Content

Introduction


Data Collection

PCE Calculation

Comparison Analysis

Conclusion

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3

4

5

6

Data Collection Time, Duration and Location

3. Data Collection

Country Location Time Duration Remark

India Midway - Chennai Off-peak 2 hours One direction, 7:00 am to 9:00 am

India Midway - Chennai Peak 2 hours One direction, 9:00 am to 11:00 am

U.S. Midway- Lincoln, NE Off-peak 2 hours One direction, 2:00 pm to 4:00 pm

U.S. Midway- Lincoln, NE Peak 2 hours One direction, 5:00 pm to 7:00 pm

India Intersection-Mumbai Off-peak 2 hoursSignalized intersection, one approach, through movement,

7:00 am to 9:00 am

Data Collection for Midway in India (Chennai)

3. Data Collection

• Data Collection Site:

- Tidal Park

• Data Collection Device:

- Infra-Red Traffic Logger (TIRTL)

• Collected Data:

- Traffic volume, instantaneous

speed, leading and lagging headway

data, vehicle type, length and width of

vehicles, percentage of trucks

Data Collection for Intersection in India (Mumbai)

3. Data Collection


- Vashi Rd & Jambul Marg

(Intersection on urban arterial roads)


- Video camera + manual + Timer

• Collected Data:

- Traffic volume, clearance time, clearance

length, vehicle type, length and width of vehicles,

red/green signal length, cycle length

Data Collection for Midway in U.S. (Lincoln, NE)

3. Data Collection


- S 84th Rd (urban arterial roads)


- Video camera + Video detectors

• Collected Data:

- Traffic volume, instantaneous

speed, leading and lagging headway

data, vehicle type, vehicle length,

percentage of trucksVideo Detectors

Data Collection for Intersection in U.S. (Lincoln, NE)

3. Data Collection


- N 27th Rd & Cornhusker Hwy

(Intersection on urban arterial roads)


- Video camera + Video detectors

• Collected Data:

- Traffic volume, instantaneous speed,

headway, vehicle type, vehicle length,

red/green signal length, cycle lengthVideo Detectors

Content

Introduction


Data Collection

PCE Calculation

Comparison Analysis

Conclusion

1

2

3

4

5

6

PCE Calculation for Midway

4. PCE Calculation

• Method:

- Headway and Speed-area method for both India and

U.S. for both off-peak and peak hours

• Aggregation Interval:

- PCEs are calculated every 10 minutes, and 12

observations for each combination of time, location and

method, 8 combinations and 96 observations in total.


4. PCE Calculation

observation

PCE-Midway

Off-peak hour Peak hour

India(2h) America(2h) India(2h) America(2h)

Speed-area Headway Speed-area Headway Speed-area Headway Speed-area Headway

1(0-10min) 1.70 1.82 1.16 1.52 2.48 3.40 1.12 1.90

2(11-20min) 1.59 3.42 1.24 1.96 1.78 2.17 1.22 1.56

3(21-30min) 1.62 2.96 1.14 1.57 2.04 2.52 1.37 1.99

4(31-40min) 1.91 2.47 1.16 1.56 1.95 2.40 1.12 1.79

5(41-50min) 1.25 1.50 1.16 1.68 2.75 2.53 1.14 1.77

6(51-60min) 1.80 2.90 1.38 1.78 2.78 2.45 1.20 1.90

7(61-70min) 1.55 3.56 1.26 1.97 1.45 2.83 1.13 1.56

8(71-80min) 1.64 2.15 1.24 1.94 2.34 3.20 1.14 1.32


4. PCE Calculation

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

5.5

6

6.5

PC

E

Observation

PCE at Midway by Headway Method

Off-peak, India Off-peak, U.S. Peak, India Peak, U.S.

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

5.5

PC

E

Observation

PCE at Midway by Speed-area Method


Summary of PCE Calculation for Midway

4. PCE Calculation

• Difference in PCEs between off-peak and peak hours in

both India and U.S. by both method may not be obvious.

• PCEs in India may be higher than U.S.

• There are more variance in PCEs in India than in U.S.

• Difference between headway-based PCEs and speed-

area-based PCEs may not be obvious for both India and

U.S.

PCE Calculation for Intersection

4. PCE Calculation

• Method:

- Delay and Speed-area method for both India and

U.S. for both off-peak and peak hours

• Aggregation Interval:

- PCEs are calculated every 4 cycles, and 11

observations for each combination of time, location and

method, 8 combinations and 88 observations in total.


4. PCE Calculation

Observation

(every 4

cycles)

PCE-Intersection

Off-peak hour Peak hour

India(2h) America(2h) India(2h) America(2h)

Speed-area-4 Delay-3 Speed-area-2 Delay-1 Speed-area-8 Delay-7 Speed-area-6 Delay-5

1(1-4) 5.36 1.24 4.8 1.41 5.26 1.28 4.92 1.84

2(5-8) 3.91 1.20 4.86 1.34 5.53 1.36 4.82 1.87

3(9-12) 3.88 1.22 4.76 1.32 5.78 1.42 4.85 1.61

4(13-16) 5.29 1.37 4.73 1.49 5.44 1.46 4.87 1.73

5(17-20) 7.16 1.91 5.00 1.60 6.03 1.64 4.85 1.85

6(21-24) 6.27 1.44 4.94 1.38 6.56 1.48 5.00 2.11

7(25-28) 5.77 1.11 5.04 1.66 5.21 1.26 4.90 1.46

8(29-32) 7.63 1.25 4.98 1.98 2.64 1.19 4.91 2.11

9(33-36) 4.29 1.16 4.8 1.58 4.41 1.22 4.84 1.52

10(37-40) 6.33 1.54 4.77 1.47 7.29 1.63 4.8 1.93

11(41-44) 6.84 1.64 4.91 1.67 5.02 1.74 4.85 1.65


4. PCE Calculation

0.8

1

1.2

1.4

1.6

1.8

2

2.2

2.4

PC

E

Observation

PCE at Intersection by Delay Method


2

2.5

3

3.5

4

4.5

5

5.5

6

6.5

7

7.5

8

PC

E

Observation

PCE at Intersection by Speed-area Method


Summary of PCE Calculation for Intersection

4. PCE Calculation

• For delay method, difference in PCEs between off-peak and

peak hours in India may not be obvious, but it may be obvious

in U.S; also, delay-based PCEs during peak hours in U.S. may

be higher than that in India.

• For speed-area method, there are more variance in PCEs in

India than in U.S; also, difference in speed-area-based PCEs

between off-peak and peak hours in U.S. may not be obvious.

• PCEs calculated by speed-area method may be much higher

than PCEs calculated by delay method in both India and U.S.

Box Plot for PCE Calculation

4. PCE Calculation

Content

Introduction


Data Collection

PCE Calculation

Comparison Analysis

Conclusion

1

2

3

4

5

6

Introduction for Statistical Comparison Analysis

5. Comparison Analysis

• Experimental units:

- PCE. PCEs at midway and intersection are separately

compared.

• Treatment design:

- Three factors (hour, country and method) with 2

levels in each factor (hour: off-peak and peak; country:

India and U.S.; method: headway/delay, speed-area).

- 8 treatments in total.

- Analyze by SAS.

Statistical Comparison Analysis for PCE at Midway


• Test effect of hour, country and methodType III Tests of Fixed Effects

Effect Num DF Den DF F Value Pr > F

hour 1 88 2.15 0.1459

country 1 88 78.81 <.0001

hour*country 1 88 1.72 0.1925

method 1 88 24.96 <.0001

hour*method 1 88 5.73 0.0188

country*method 1 88 0.33 0.5667

hour*country*metho

d1 88 8.30 0.0050

*Three–way interaction of hour, country and method is significant.

*Values of PCE may be affected by “hour”, “country” and “method”

three factors.



• Compare PCEs in India and America for off-peak hours

Estimates

Label Estimate Standard Error DF t Value Pr > |t|

America vs India, offpeak,

headway-1.2608 0.2288 88 -5.51 <.0001


speedarea-0.4700 0.2288 88 -2.05 0.0429

*Both headway-based and speed-area-based PCEs in India are

significantly higher than in U.S. during off-peak hours.

*During off-peak hours, trucks in India have more longitudinal and

lateral effects on other vehicles than in U.S.



• Compare PCEs in India and America for peak hours

Estimates


America vs India, peak,

headway-0.9021 0.2288 88 -3.94 0.0002


speedarea-1.4297 0.2288 88 -6.25 <.0001

*Both headway-based and speed-area based PCEs in India are

significantly higher than in U.S. during peak hours.

*During peak hours, trucks in India have more longitudinal and lateral

effects on other vehicles than in U.S.



• Compare PCEs in India and America for all hours

Estimates


America vs India, all,

headway-1.0814 0.1618 88 -6.68 <.0001


speedarea-0.9498 0.1618 88 -5.87 <.0001

*Both headway-based and speed-area based PCEs in India are

significantly higher than in U.S. for all hours.

*During all hours, trucks in India have more longitudinal and lateral

effects on other vehicles than in U.S.

Statistical Comparison Analysis for PCE at Midway - Summary


No matter during off-peak or peak hours, both headway-based and

speed-area-based PCEs of trucks at midway in India is higher than that

in U.S.;

On the other words, no matter during off-peak or peak hours, trucks at

midway in India have more longitudinal and lateral effect on other

vehicles than that in U.S.

Statistical Comparison Analysis for PCE at Intersection


• Test effect of hour, country and methodType III Tests of Fixed Effects

Effect Num DF Den DF F Value Pr > F

hour 1 80 0.00 0.9788

country1 80 2.18 0.1436

hour*country1 80 0.92 0.3410

method1 80 723.79 <.0001

hour*method1 80 1.32 0.2532

country*method1 80 11.65 0.0010

hour*country*metho

d

1 80 0.05 0.8165

*Two–way interaction of country and method is significant; method is significant.

*Values of PCE may be affected by “country” and “method” , not affected by

“hour”.



• Compare PCEs in India and America for off-peak hours

Estimates



delay0.1655 0.2733 80 0.61 0.5466


speedarea-0.8309 0.2733 80 -3.04 0.0032*During off-peak hours, speed-area-based PCEs in India are significantly higher

than in U.S.; while difference in delay-based-PCEs between India and U.S. is not

significant.

*During off-peak hours, trucks in India and U.S. have same degree of longitudinal

effect on other vehicles; while trucks in India have more lateral effect on other

vehicles than in U.S.



• Compare PCEs in India and America for peak hours

Estimates



delay0.3636 0.2733 80 1.33 0.1871


speedarea-0.5055 0.2733 80 -1.85 0.0681*During peak hours, speed-area-based PCEs in India are significantly higher than in

U.S. (noticed: although p-value > 0.05, it is much closer to 0.05 than other difference);

while difference in delay-based-PCEs between India and U.S. is not significant.

*During peak hours, trucks in India and U.S. have same degree of longitudinal effect

on other vehicles; while trucks in India have more lateral effect on other vehicles than

in U.S.



• Compare PCEs in India and America for all hours

Estimates


America vs India, all, delay 0.2645 0.1933 80 1.37 0.1749


speedarea-0.6682 0.1933 80 -3.46 0.0009

*During all hours, speed-area-based PCEs in India are significantly higher than

in U.S.; while difference in delay-based-PCEs between India and U.S. is not

significant.

*During all hours, trucks in India and U.S. have same degree of longitudinal

effect on other vehicles; while trucks in India have more lateral effect on other

vehicles than in U.S.

Statistical Comparison Analysis for PCE at Intersection - Summary


No matter during off-peak or peak hours, there is no difference in

delay-based PCE of trucks at intersection between India and U.S.;


intersection in India and U.S. have similar longitudinal effect on other

vehicles.

No matter during off-peak or peak hours, speed-area-based PCE of

trucks at intersection in India is higher than that in U.S. ;


intersection in India have more lateral effect on other vehicles than that

in U.S.

Content

Introduction


Data Collection

PCE Calculation

Comparison Analysis

Conclusion

1

2

3

4

5

6

Conclusions for Research

6. Conclusion

• At midway, no matter during off-peak or peak hours, trucks in

India have more longitudinal and lateral effects on other

vehicles than that in U.S.

• At intersection, trucks in India have more lateral effects on

other vehicles than that in U.S. for both off-peak and peak

hour; however, trucks in India and U.S. have similar

longitudinal effect on other vehicles for both off-peak and peak

hour.

Recommended PCE Values based on Research

6. Conclusion

Midway Intersection

Headway Speed-area Delay Speed-area

U.S. 1.7 1.2 1.7 4.9

India 2.8 2.1 1.4 5.5

Our Works

6. Conclusion

• IITM:

- Data collection and PCE calculation for Midway, Chennai

• IITB:

- Data collection and PCE calculation for Intersection, Mumbai

• UNL:

- Data collection and PCE calculation for Lincoln, NE

• IITM, IITB and UNL:

- Comparison analysis, draw conclusion and prepare slides

References

6. Conclusion

• Krammes, Raymond A., and Kenneth W. Crowley. "Passenger

car equivalents for trucks on level freeway segments."

Transportation Research Record 1091 (1986).

• Benekohal, Rahim F., and Weixiong Zhao. "Delay-based

passenger car equivalents for trucks at signalized

intersections." Transportation Research Part A: Policy and

Practice 34.6 (2000): 437-457.

• Chandra, Satish, and P. K. Sikdar. "Factors affecting PCU in

mixed traffic situations on urban roads." Road and transport

research 9.3 (2000): 40-50.

comparison of pcu for indian and american conditions

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