Estimating Passenger Car Equivalent using the HCM-6 PCE Methodology on Four-Lane Level Freeway Segments in Western U.S.

2019 ◽  
Vol 2673 (11) ◽  
pp. 529-545 ◽  
Author(s):  
Jianan Zhou ◽  
Laurence Rilett ◽  
Elizabeth Jones
Keyword(s):  
Flow Speed ◽  
Free Flow ◽  
Passenger Cars ◽  
Highway Capacity ◽  
Passenger Car ◽  
Highway Capacity Manual ◽  
Free Flow Speed ◽  
Passenger Car Equivalent ◽  
Equal Capacity ◽  
Using Data

The passenger car equivalent (PCE) of a truck is used to account for the presence of trucks in the Highway Capacity Manual (HCM). The HCM-6 employed an equivalency capacity methodology to estimate PCE. It is hypothesized in this paper that the HCM-6 PCE values are not appropriate for the western U.S., which consistently experiences truck percentages higher than 25%. Furthermore, the HCM PCE procedure assumes that truck and passenger cars travel at the same desired free-flow speed on level terrain. However, many heavy trucks in the western U.S. are governed through the use of speed limiters so that their speeds are considerably less than the speed limit. Thirdly, the HCM-6 PCEs are based on the freeways having three lanes per direction, which might not be appropriate for the freeways with two lanes per direction that predominate in the rural sections of the western U.S. Lastly, the trucks used in the HCM-6 simulation might not be representative of the empirical trucks observed on rural freeways in western states. This paper examines these effects on PCEs using data from I-80 in western Nebraska. The PCEs were estimated using the HCM-6 equal-capacity method and VISSIM 9.0 simulation data under (1) the HCM-6 conditions and (2) the Nebraska empirical conditions. It was found that the PCEs recommended in HCM-6 underestimate the effects of trucks on four-lane level freeway segments that experience high truck percentages having large differences in free-flow speed distributions, and which have different truck lengths.

Application of Moving Car Observer Method for Measuring Free Flow Speed on Two-lane Highways

2014 ◽  
Vol 69 (6) ◽  
Author(s):  
Othman Che Puan ◽  
Muttaka Na’iya Ibrahim ◽  
Usman Tasiu Abdurrahman
Keyword(s):  
Field Measurement ◽  
Flow Speed ◽  
Operating Conditions ◽  
Free Flow ◽  
Geometric Features ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Free Flow Speed ◽  
The Subject ◽  
Low Traffic

There exists a need to evaluate the performance indicator that reflects the current level of service (LOS) of the subject facility to justify any decision making on expenditures to be made for improving the performance level of a road facility. Free-flow speed (FFS) is one of the key parameters associated with LOS assessment for two-lane highways. Application of a more realistic approach for assessing road’s performance indicators would result in better estimates which could in turn suggest the most appropriate decision to be made (for situations where upgrading is needed); especially, in terms of finance, materials and human resources. FFS is the driver’s desired speed at low traffic volume condition and in the absence of traffic control devices. Its estimation is significant in the analysis of two-lane highways through which average travel speed (ATS); an LOS indicator for the subject road class is determined. The Highway Capacity Manual (HCM) 2010 offers an indirect method for field estimation of FSS based on the highway operating conditions in terms of base-free-flow-speed (BFFS). It is however, recommended by the same manual that direct field FSS measurement approach is most preferred. The Malaysian Highway Capacity Manual (MHCM) established a model for estimating FFS based on BFFS, the geometric features of the highway and proportion of motorcycles in the traffic stream. Estimating FFS based on BFFS is regarded as an indirect approach which is only resorted to, if direct field measurement proved difficult or not feasible. This paper presents the application of moving car observer (MCO) method for direct field measurement of FFS. Data for the study were collected on six segments of two-lane highways with varying geometric features. FFS estimates from MCO method were compared with those based on MHCM model. Findings from the study revealed that FFS values from MCO method seem to be consistently lower than those based on MHCM model. To ascertain the extent of the difference between the FFS values from the two approaches, student t-statistics was used. The t-statistics revealed a P–value of less than 0.05 (P < 0.05) which implies that there is a statistically significant difference between the two sets of data. Since MCO method was conducted under low traffic flow (most desired condition for field observation), it can be suggested that MCO estimates of FFS represent the actual scenario. A relationship was therefore developed between the estimates from the two methods. Thus, if the MHCM model is to be applied, the measured value needs to be adjusted based on the relationship developed between the two approaches.

Sensitivity Analysis of Speed Limit, Truck Lane Restrictions, and Data Aggregation Level on the HCM-6 Passenger Car Equivalent Estimation Methodology for Western U.S. Conditions

2019 ◽  
Vol 2673 (11) ◽  
pp. 493-504
Author(s):  
Jianan Zhou ◽  
Laurence Rilett ◽  
Elizabeth Jones
Keyword(s):  
Data Aggregation ◽  
Companion Paper ◽  
Flow Speed ◽  
Speed Limit ◽  
Passenger Cars ◽  
Highway Capacity ◽  
Passenger Car ◽  
Highway Capacity Manual ◽  
Negative Impacts ◽  
The Impact

In the 2016 Highway Capacity Manual (HCM-6), the impact of trucks on freeway operations is measured by passenger car equivalents (PCEs). PCEs are estimated by the equal capacity methodology. The HCM-6 PCE values are based on the assumptions that passenger cars and trucks travel at the same free-flow speed, that they travel on freeways with three lanes per direction, and that they travel in traffic with no more than 25% trucks. On Interstate 80 in western Nebraska, it is observed that the interaction of high truck percentages and large speed differences between passenger cars and trucks may result in moving bottlenecks. It was hypothesized that the current HCM-6 PCEs may be not appropriate for these conditions. A companion paper showed this was true and that the major cause was speed differentials between trucks and passenger cars. In essence, when slow-moving trucks pass each other they create moving bottlenecks, which results in increased PCE values. This paper is an extension to a companion paper and examines a number of issues related to estimation of PCEs. The paper examines the effect of speed limit, truck passing restrictions, and data aggregation interval on PCEs. The results show that: (i) if a higher speed limit is implemented, trucks will affect the passenger cars more severely; (ii) if truck passing is restricted by lane restrictions, the negative impacts of trucks on passenger car operation may be mitigated; and (iii) using a longer data aggregation interval results in lower PCE values, all else being equal.

scholarly journals Delay-based Passenger Car Equivalent at Signalized Intersections in Iran

2017 ◽  
Vol 29 (2) ◽  
pp. 135-142 ◽  
Author(s):  
Habibollah Nassiri ◽  
Sara Tabatabaie ◽  
Sina Sahebi
Keyword(s):  
Signalized Intersections ◽  
Simulation Software ◽  
Heavy Vehicles ◽  
Passenger Cars ◽  
Highway Capacity ◽  
Passenger Car ◽  
Highway Capacity Manual ◽  
Operational Characteristics ◽  
Passenger Car Equivalent ◽  
Traffic Operation

Due to their different sizes and operational characteristics, vehicles other than passenger cars have a different influence on traffic operations especially at intersections. The passenger car equivalent (PCE) is the parameter that shows how many passenger cars must be substituted for a specific heavy vehicle to represent its influence on traffic operation. PCE is commonly estimated using headway-based methods that consider the excess headway utilized by heavy vehicles. In this research, the PCE was estimated based on the delay parameter at three signalized intersections in Tehran, Iran. The data collected were traffic volume, travel time for each movement, signalization, and geometric design information. These data were analysed and three different models, one for each intersection, were constructed and calibrated using TRAF-NETSIM simulation software for unsaturated traffic conditions. PCE was estimated under different scenarios and the number of approach movements at each intersection. The results showed that for approaches with only one movement, PCE varies from 1.1 to 1.65. Similarly, for approaches with two and three movements, the PCE varies from 1.07 to 1.99 and from 0.76 to 3.6, respectively. In addition, a general model was developed for predicting PCE for intersections with all of the movements considered. The results obtained from this model showed that the average PCE of 1.5 is similar to the value recommended by the HCM (Highway Capacity Manual) 1985. However, the predicted PCE value of 1.9 for saturated threshold is closer to the PCE value of 2 which was recommended by the HCM 2000 and HCM 2010.

scholarly journals Passenger Car Equivalent Value for Commercial Vehicles: A New Approach

2021 ◽  
Author(s):  
Efstathios Bouhouras ◽  
Socrates Basbas
Keyword(s):  
Field Survey ◽  
Research Area ◽  
Commercial Vehicles ◽  
Passenger Cars ◽  
Highway Capacity ◽  
Passenger Car ◽  
Highway Capacity Manual ◽  
Equivalent Number ◽  
Passenger Car Equivalent ◽  
Extended Field

Within the framework of the present paper an attempt has been made to develop a methodology for the calculation of a Passenger Car Equivalent (PCE) factor in order to express the number of commercial vehicles in the equivalent number of passenger cars. The methodology is based on the Highway Capacity Manual, the examination of the international literature and an extended field survey. The research area is the Municipality of Thessaloniki, Greece and specifically 27 at-grade, signalized intersections which were examined. The field survey was performed during two time-periods in order a comparison to be possible.

Estimating Passenger Car Equivalents on Level Freeway Segments Experiencing High Truck Percentages and Differential Average Speeds

2018 ◽  
Vol 2672 (15) ◽  
pp. 44-54 ◽  
Author(s):  
Jianan Zhou ◽  
Laurence Rilett ◽  
Elizabeth Jones ◽  
Yifeng Chen
Keyword(s):  
United States ◽  
Simulation Models ◽  
Flow Speed ◽  
Free Flow ◽  
Western United States ◽  
Passenger Cars ◽  
Passenger Car ◽  
Highway Capacity Manual ◽  
Heavy Trucks ◽  
Equal Density

In the Highway Capacity Manual (HCM), the passenger car equivalent (PCE) of a truck is used to account for the impacts of trucks on traffic flow. The 2010 HCM PCE values were estimated by the equal-density method using a FRESIM simulation. It was determined that the truck PCE for level freeway segments was 1.5 for all conditions. In the 2016 HCM, the PCE values were based on VISSIM simulation output at 1 min intervals along a three-lane, 13 mile (8 mile level and 5 mile graded) section of a roadway. It was determined that the truck PCE for level freeway segments was 2.0. It is hypothesized in this paper that the HCM PCE values are not appropriate for the western United States, which consistently experiences truck percentages higher than 25%, the maximum truck percentage published in the HCM PCE table. The HCM PCE procedure assumes that truck and passenger cars travel at the same average free-flow speed on level terrain. However, many heavy trucks in the western United States have speed limiters to improve fuel economy, and therefore travel slower than the speed limit. The interaction of high truck percentages and large speed differences may result in moving bottlenecks when trucks pass other trucks at low speed differentials. This may lead to an increased delay for the following passenger car vehicles. The 2016 HCM PCEs are based on three-lane simulations where the PCE is calculated based on near-capacity flows. This approach might not be appropriate for western states where these conditions rarely exist. This paper examines these effects using data from I-80 in western Nebraska. The paper develops new PCE values based on the 2010 HCM equal-density approach using calibrated CORSIM and VISSIM simulation models. It was found that the PCE values in the HCM 2010 and HCM 2016 underestimate the effect of heavy trucks on level terrain freeways that experience high truck percentages, and where different vehicle types have large differences in average free-flow speeds.

Determining Passenger Car Equivalent for Motorcycle at Mid-Block of Sesetan Road

2015 ◽  
Vol 776 ◽  
pp. 95-100
Author(s):  
I. Gusti Raka Purbanto
Keyword(s):  
Motor Vehicles ◽  
Heavy Vehicles ◽  
Highway Capacity ◽  
Passenger Car ◽  
Highway Capacity Manual ◽  
The Road ◽  
Traffic Conditions ◽  
Mode Share ◽  
Passenger Car Equivalent ◽  
On The Road

Motorcycle dominates traffic in Bali, particularly in urban roads, which occupy more than 85% of mode share. The three types of vehicles, i.e. motorcycles, heavy and light vehicles share the roadways together. Under mixed traffic conditions, motorcycle may be travelling in between and alongside two consecutive motor vehicles. Considering such a situation, passenger car equivalent values should be examined thoroughly. This study aims to determine passenger car equivalent (PCEs) of motorcycle at mid-block of Sesetan Road. Three approaches are used to examine the PCEs values. This study found that the PCE of motorcycles are in a range between 0.2 and 0.4. This values are about the same to the existing PCE of the Indonesian Highway Capacity Manual (1997). This study also pointed out that motorcyclists and car drivers may behave differently to the existence of motorcycles. Car drivers are more aware than motorcyclists on the existence of motorcycle on the road. Further, more samples are required to obtain comprehensive results. In addition, the presence of heavy vehicles need to be considered for future study.

scholarly journals MICROSIMULATION-BASED PASSENGER CAR EQUIVALENTS FOR HEAVY VEHICLES DRIVING TURBO-ROUNDABOUTS

Transport ◽  
2016 ◽  
Vol 31 (2) ◽  
pp. 295-303 ◽  
Author(s):  
Orazio Giuffrè ◽  
Anna Granà ◽  
Sergio Marino ◽  
Fabio Galatioto
Keyword(s):  
Geometric Design ◽  
Heavy Vehicles ◽  
Passenger Cars ◽  
Highway Capacity ◽  
Passenger Car ◽  
Operational Conditions ◽  
Highway Capacity Manual ◽  
Traffic Conditions ◽  
Scenarios Simulation

Due to its geometric design, turbo-roundabouts impose greatest constraints to the vehicular trajectories; by consequence, one can expect a more unfavourable impact of heavy vehicles on the traffic conditions than on other types of roundabouts. The present paper addresses the question of how to estimate Passenger Car Equivalents (PCEs) for heavy vehicles driving turbo-roundabouts. The microsimulation approach used revealed as a useful tool for evaluating the variation of quality of traffic in presence of mixed fleets (different percentages of heavy vehicles). Based on the output of multiple runs of several scenarios simulation, capacity functions for each entry lane of the turbo-roundabout were developed and variability of the PCEs for heavy vehicles were calculated by comparing results for a fleet of passenger cars only with those of the mixed fleet scenarios. Results show a dependence of PCEs for heavy vehicles on operational conditions, which characterise the turbo-roundabout. Assuming the values of PCEs for roundabouts provided by the 2010 Highway Capacity Manual (HCM), depending on entering manoeuvring underestimation and overestimation of the effect of heavy vehicles on the quality of traffic conditions have been found.

Effect of Lane Width on Speeds of Cars and Heavy Vehicles in Work Zones

2005 ◽  
Vol 1920 (1) ◽  
pp. 41-48 ◽  
Author(s):  
Madhav V. Chitturi ◽  
Rahim F. Benekohal
Keyword(s):  
Flow Speed ◽  
Heavy Vehicles ◽  
Work Zones ◽  
Passenger Cars ◽  
Highway Capacity ◽  
Speed Reduction ◽  
Interstate Highways ◽  
Highway Capacity Manual ◽  
Traffic Stream ◽  
Lane Width

Traffic data were collected from 11 work zones on Interstate highways in Illinois in which one of the two lanes was open. The reductions in free-flow speed (FFS) due to narrow lanes and lateral clearances in work zones were studied. It was found that the reductions in FFSs of vehicles in work zones because of narrow lanes were higher than the reductions given in the Highway Capacity Manual for basic freeway sections. The data also showed that the narrower the lane was, the greater the speed reduction was. The data showed that the FFSs of heavy vehicles were statistically lower than the FFSs of passenger cars, even though the speed limit was the same for both types of vehicles. In addition, the reduction in the FFSs of heavy vehicles was greater than the reduction in the FFSs of passenger cars. This greater reduction in the speed of heavy vehicles affected the performance of the traffic stream in work zones. Thus, it should be considered in the computation of the passenger car equivalence for heavy vehicles. It is recommended that 10, 7, 4.4, and 2.1 mph be used for speed reduction in work zones for lane widths of 10, 10.5, 11, and 11.5 ft, respectively.

scholarly journals Self-Organizing Tree Algorithm (SOTA) Clustering for Defining Level of Service (LOS) Criteria of Urban Streets

2018 ◽  
Vol 47 (4) ◽  
pp. 309-317
Author(s):  
Amit Kumar Das ◽  
Prasanta Kumar Bhuyan
Keyword(s):  
Travel Speed ◽  
Flow Speed ◽  
Free Flow ◽  
Level Of Service ◽  
Highway Capacity ◽  
Tree Algorithm ◽  
Highway Capacity Manual ◽  
Urban Streets ◽  
Flow Speeds ◽  
Self Organizing

This study is intended to define the Free Flow Speed (FFS) ranges of urban street classes and speed ranges of Level of Service (LOS) categories. In order to accomplish the study FFS data and average travel speed data were collected on five urban road corridors in the city of Mumbai, India. Mid-sized vehicle (car) mounted with Global Positioning System (GPS) device was used for the collection of large number of speed data. Self-Organizing Tree Algorithm (SOTA) clustering method and five cluster validation measures were used to classify the urban streets and LOS categories. The above study divulges that the speed ranges for different LOS categories are lower than that suggested by Highway Capacity Manual (HCM) 2000. Also it has been observed that average travel speed of LOS categories expressed in percentage of free flow speeds closely resembles the percentages mentioned in HCM 2010.

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