Passenger Car Unit Values Research Articles

Analysis of Traffic Performance and Passenger Car Equivalent Value in Tangerang – Merak Toll Road Section

Economic growth involves massive movement of logistics, where goods transported by land become the main choice by supplier. One of them being the main access for connecting Java and Sumatera is the Tangerang – Merak toll road. An increase in traffic volume occurs every year, followed by additional problems such as congestion which obviously affects traffic performance. Given this reason, it is necessary to evaluate traffic performance through parameter assessments, which are the degree of saturation and travel speed. This research was carried out on the Tangerang - Merak toll road section KM 32,300 to KM 35,500 towards Jakarta for one week using traffic CCTV recordings, then selected on 17 April 2024. The calculation results obtained for each average weighted value for the degree of saturation (Ds) at 0.36 and average of the Space Mean Speed is at 33.08 kph. Based on traffic performance analysis, the volume parameter does not indicate a problem, and is included in the LOS A category. However, the travel speed parameter shows an issue and included in the LOS F category. This will be the focus problem within the scope of the research. On the other side, traffic composition which includes variations in the number of vehicles per time and type of vehicle. Given this kind of variation, a Passenger Car Unit value is needed that can equalize the existing different vehicle types into a uniform standard, including who commit over dimensional violations. Where the value of passenger car equivalent of an over-dimensional vehicle is changing, it is necessary to re-calibrate the emp value. Researchers used the Volume Delay Function formula to calculate travel time, then explore a combination of emp values using the dynamic programming method by comparing survey travel time with the simulation one. The difference between the PKJI standard value and the calibrated pce value proves the problem of these vehicles commit over dimension violations on the Tangerang – Merak toll road. For this reason, it is hoped that this research which evaluate traffic performance, travel time and passenger car equivalent values, can be used as a basis for further policy making to improve the performance of the Tangerang – Merak toll road.

Determination of Passenger Car Unit and Capacity at Grades of Two Lane Undivided Highway: A Case Study of Khurkot–Dhulikhel Section of BP Highway

The majority of Nepal’s National Highway and feeder road system comprises two-lane highways with heterogeneous traffic conditions. Factors such as lane width, gradient, lateral clearance, and shoulder conditions can influence the passenger car unit (PCU) and roadway capacity. Recognizing that grade magnitude (%) is an important yet unexplored roadway factor in Nepal, and the present study primarily aims to estimate the passenger car unit on two-lane undivided hilly roads with gradients under prevailing heterogonous traffic conditions. This study aims to determine the PCU values and roadway capacity at grade under mixed nature traffic flow for a two-lane undivided highway. In this research, the necessary data were collected at five sections of BP highways using a digital video recorder, which was then analyzed to assess traffic characteristics and calculate PCU values. Using the PCU values, the road capacity was estimated using Greenshield’s model. For capacity estimation, flow and density were addressed using dynamic PCU values. This study reveals that the PCU of all categorized vehicles increases linearly with the increase in gradient while roadway capacity decreases with an increase in grade. It was observed that PCU values obtained for two-wheelers in all sections are smaller than the PCU values specified in NRS 2013, whereas for buses, trucks, and LCVs, they are higher than the PCUs given in NRS 2013. The study highlights the impact of road grade on the PCU for different vehicle categories on a highway. Additionally, the study demonstrates that the developed capacity values are realistic and consistent with the values presented in the Highway Capacity Manual (HCM) of developing countries such as Indonesia and China. These results are expected to be beneficial for practitioners and the ongoing effort to develop a highway capacity manual.

Methodology to Counter Heterogeneity at Urban Multilane Roundabouts

Despite the adoption of roundabouts in developing countries for traffic management and smooth flow, the concept of traffic heterogeneity management at these intersections is relatively unexplored. Estimating passenger car units (PCUs) for different vehicle types to homogenize traffic is a recognized approach worldwide. In this study, vehicles were classified into five categories to provide a meaningful context for the analysis. The study proposes a model to estimate PCU values for different vehicle types, specifically at roundabouts, after identifying the potential influencing factors. The study was based on data collected from 10 roundabouts in three Indian cities, having different physical and geometrical characteristics. The proposed method yielded PCU values that were partially comparable with existing standards. Comparisons with the Indian Highway Capacity Manual (Indo-HCM) revealed that this publication underestimated PCU values for two-wheelers and three-wheelers by 20% and 11% respectively, but overestimated PCU values for big cars and heavy vehicles by 9% and 12%, respectively. Method appropriateness was ascertained from the lack of prior assumptions made about traffic and geometrical characteristics. To prevent unnecessary re-estimation of PCU values across locations, the idea of a heterogeneity counter component (HCC) was proposed. The model was trained using cross validation on a dataset of seven roundabouts, and its performance was evaluated on a separate dataset using mean absolute percentage error. The relationship between PCUs and the geometrical features of roundabouts, and the effect of traffic characteristics on HCC were studied. The findings might be considered while revising relevant codes and manuals (e.g., IRC-65:2017, Indo-HCM).

Estimation of PCU’s in Heterogeneous Traffic by Different methods

Transportation gets more intricate when cities get busier. Increased motor vehicles are moving into towns, which means increased traffic jams. The impacts of urbanisation are pervasive and include, but are not limited to, traffic performance, road safety, pollution, and traffic congestion. The rising number of people in the nation is driving up demand for personal vehicles including cars and motorcycles. Adding additional lanes is not enough to solve traffic congestion effectively. So, studying passenger car units (PCU) in heterogeneous traffic becomes necessary. Efforts to derive PCU values for cities roads with various traffic situations are made on this article. Using the density technique, we got somewhat different PCU values for the remaining three cars, but Chandra's method gave us PCU values of 1.99, 3.37, and 1.33, respectively. The data shows that buses make up a significant portion of the traffic in this region, constituting 23% of the total. Of the entire traffic volume, cars account for 16%. There are 19% fewer cars and trucks on two wheels in the research region. Of the total vehicles in the research region, buses constitute 21%. Nineteen percent of all traffic is caused by cars. It has been found that according to site 1 in the research region, three-wheeled vehicles constitute 18% of total traffic.

The Evaluation of the Impact of Road Width on Passenger Car Units (PCU) in Heterogeneous Traffic Conditions

This study delves into the utilization of Passenger Car Units (PCU) as a pivotal metric for gauging the influence of diverse vehicle types on traffic flow. Focusing on the context of Mogadishu, data acquisition was conducted across eight key sections of major highways. Employing digital video recorders, the gathered data facilitated a comprehensive analysis of traffic dynamics, thereby enabling the computation of PCU values. The investigation unveiled a discernible trend wherein the traffic makeup, comprising bus, truck, light commercial vehicle (LCV), and car categories exhibited a positive correlation with carriageway width expansion. Nevertheless, the volume composition peaked notably in narrower carriageway widths. Concurrently, the speed of the aforementioned vehicle categories showcased a linear progression proportional to carriageway width augmentation. Intriguingly, PCU values assigned to motorcycles consistently undershot the figures stipulated in the Mogadishu Road Standards (MRS). Conversely, PCU values for bus, truck, and LCV categories consistently surpassed the MRS 2070 benchmarks. This scrutiny distinctly elucidated the intricate interplay between lane width and PCU values across distinct vehicle types, effectively underscoring the propensity of PCU values to escalate with escalating carriageway dimensions.

Different methods for estimation of dynamic passenger car units – A review

In India, heterogeneous traffic conditions are prevailing due to a variety of vehicles with different static and dynamic characteristics. It is necessary to convert mixed traffic into homogeneous traffic by using Passenger Car Unit (PCU) values. Roadway and traffic conditions on urban roads vary considerably across the cities which generally affects the PCU values of different vehicles and the capacity of the roadway. This shows the dynamic nature of PCU values. PCU values are widely used in traffic capacity analysis, determination of Level Of Service (LOS), saturation flow rate, signal design and coordination, and development of traffic flow models. Because of these wide applications, the accuracy of dynamic PCU values is very important. Many researches have been carried out on the estimation of dynamic PCU values. This paper presents different methods for estimating dynamic PCU appropriate for heterogeneous traffic conditions on Indian roads. The challenges in estimating PCU values and future directions for improving the PCU estimation methods are also presented in this paper.

Concept of heterogeneity index for urban mixed traffic

• This paper conceptualizes a new measure to quantify the heterogeneity of mixed traffic. A proportion-based variant of COV of dynamic PCU values is proposed for this purpose. • This study develops a ‘Gaussian Process Regression’-based classified speed model which is further used to estimate the PCU of different vehicle categories and determine the ‘Heterogeneity Index’ of the mixed traffic stream. • The study proposes the heterogeneity levels using the K-medoids clustering technique along with Davies-Bouldin Index and Silhouette Index as validation measures. • Sensitivity analysis performed in the study shows the effect of traffic volume, traffic composition, and classified speed on the proposed ‘Heterogeneity Index’. Heterogeneity is one of those characteristics which differentiate traffic conditions of a developing country from other developed nations. The heterogeneity which represents the diversity among vehicle categories is suspected to have adverse influences on lane discipline, congestion potential, and road users’ safety. However, the influence of heterogeneity on the above-mentioned parameters has been only measured indirectly by considering traffic composition as an indicator of the prevailed heterogeneity-level. No direct relationship between the heterogeneity and other parameters has been established as there is no methodology available yet for quantifying the heterogeneity of mixed traffic. The present study addresses this problem and conceptualizes the ‘Heterogeneity Index’ (HI) to quantify the heterogeneity present in a mixed traffic stream. HI is conceived as a measure of the dispersion of Passenger Car Units (PCU) for different vehicle categories from its central value. A higher value of HI signifies more diverse vehicle categories present in the traffic stream. PCU of a vehicle category was estimated using the speed-based method and the individual speeds were predicted based on classified volumes using the Gaussian Process Regression model developed in this study. This paper also recommends several categorical levels for easy perception about the intensity of heterogeneity. Further, the sensitivity analysis explored the dynamic aspects of HI. Results showcased how the HI of a traffic stream may vary subject to the combined or the individual change in traffic volume, traffic composition and classified speeds. The outcomes of the study will be useful to estimate the intensity of heterogeneity that prevailed within a mixed traffic stream with varying traffic conditions.

Two-Lane Highway Capacity Estimation Based on Geometric Features

Abstract The majority of roads in most countries are two-lane highways. These lanes quickly reach their capacity and must be upgraded on a regular basis. To do so, we must first determine the capacity of the street. The primary objective of this study was to determine the effect of carriageway width, the radius of the horizontal curve, and gradients on Passenger Car Unit (PCU) values as well as on capacity of two-lane undivided Highways, and more importantly, to develop a multiple linear regression model to determine the capacity of the highway when all of these factors are present, which has not been previously reported. Green shield’s model was used to estimate the capacity of each element for all thirty-six sections using flow and speed data. Different models were built using regression analysis to estimate capacity independently, and the combined model was developed as a result. It has been noted that with proportionate increases in carriageway width and radius of the curve, there is an equivalent rise in PCU values and highway capacity, providing improved comfort and safety to road users. It was also discovered that when the value of the gradient increases cause increase in PCU values but the highway capacity decreases, thereby increasing the vehicle operating cost. Where all of these characteristics are present simultaneously in a section, the resulting multiple linear regression model was proven to be appropriate. It is believed to be valuable to practitioners as well as in the development or revision of Indian highway capacity manuals.

Passenger car units for different midblock sections in Sri Lanka under mixed traffic condition

Traffic-related analyses are essential to implementing traffic management approaches to create mobility more convenient. In this context, Passenger Car Unit (PCU) values as a uniform measure of vehicles are instrumental in analysis such as traffic capacity estimation, traffic flow model development, level of service determination, etc. These studies always demand a recently calculated set of PCU values since the traffic conditions in arterials often change. PCU values for expressway and three-lane (one-way) road types have not been calculated in the Sri Lankan context, and the available set of values has become somewhat outdated. Hence, this study used Chandra's method to assess the PCU values of ten vehicle categories for four different mid-block road sections in the Colombo district, Sri Lanka. The data relating to the two main variables of this method, categorical speed, and area of vehicles, were collected from field surveys. The results of four-lane arterials were aggregated and compared with the existing PCU values, intending to propose an updated set for general transportation studies in Sri Lanka.

Autonomous vehicle impact on improving road network vulnerability

PurposeThis study first presents a method to identify the parameters increasing road vulnerability on a macroscopic road network model. The second part exploresthe effect size difference of the analyzed attributes on network vulnerability through the implementation of different autonomous vehicles (AVs) penetrations and automation levels.MethodsThe road traffic network of Budapest, Hungary on PTV VISUM is studied by adopting a passenger car unit factor procedure to simulate the effect of AVs on road saturation. Five link parameters were used: length, distance from the centre, speed, number of lanes, and number of connectors. Network vulnerability was studied by simulating a combination of road elimination process with different passenger car unit values for AVs.ResultsThe analysis found the number of road lanes is the most significant parameter, affecting the link criticality; followed by road length and distance from the centre. The analysis of four AV scenarios with different AV penetration and level of automation showed huge effect differences ranging from 3.50% for a simple AV automation level with low AV percentage to as large to 28.53% for a fully automated fleet.ConclusionsAV implementation has proved efficient in reducing the amount of travel delays in the case of road failure. Finally, it was found that the number of lanes remained the most significant influencing parameter on travel delay. The main question is to discover the effect size difference of the analyzed attributes on network vulnerability through the implementation of different AVs penetrations and automation levels.

Macroscopic Modelling of Predicted Automated Vehicle Emissions

This paper studies the effect of automated vehicle implementation on transport system emission from a macroscopic point of view. The paper considers several scenarios differing in passenger car unit (PCU) and the penetration share percent of automated vehicles in the system using PTV Visum software. The study presents that automated vehicles reduce total emission by both the effect of smooth driving of each automated vehicle independently and the spread of automated vehicles in the network. Furthermore, apart from considering the effect of different PCU values and penetration levels, the developed model takes into account three different types of emissions and seven different vehicle classes.

Estimation of PCU Values for Urban Roads by Considering the Effect of Signalized Intersections under Mixed Traffic Conditions

Along with multiple classes of vehicles, frequent signalized intersections on the urban roads and the platoons thus created add complexity to the estimation of Passenger Car Units (PCU). Under such scenarios of interrupted traffic, a new approach based on platoon movement of vehicles is introduced for the realistic estimation of PCU values for urban roads by incorporating the appropriate vehicle behavior and interactions. The PCU values were derived by finding the trade-off between the speed reduction caused by the flow of passenger cars and other vehicle classes, as per the given definition by Transport Research Laboratory (TRL). However, the speed-flow, as well as the speed-density relations, were analyzed and found that later is preferred for the realistic estimation of PCUs for urban roads. The speed reduction is modeled using multiple linear regression with field data collected from typical urban roads characterized by platoon flow in Mumbai city (India).

TRAFFIC VOLUME STUDY AND CONGESTION SOLUTIONS

Traffic Engineering is used to accomplish secure and time bound commutation of persons and freights on road network which in turn relies on traffic flow. Due to an increase in the standard of living of middle-class families in the last decade, traffic volume has considerably increased. Thus, lack of proper management of roads can result in non-sustainable development. This work analyses traffic properties of Shivaji Marg, Janakpuri district centre, Delhi, India by performing direct manual counting method of survey. Objective of this study is to record traffic volume of the site for the weekdays from 8AM to 2PM, determine the morning peak hour and the morning peak hour factor using the standard passenger car unit (PCU) values. Also, this study attempts to determine the practical PCU values for different automobiles running on the site and calculate the corresponding morning peak hour factor. Lastly, this work comments on the congestion level of the site by comparing the recorded hourly traffic volume with the permissible volume per hour. The study found out that the practical PCU values differ from their corresponding standard values as it depends on the speed and space occupied by the automobiles which can vary from site to site. Also, it was found that the hourly traffic volume is within the permissible limit implying no congestion in the current scenario. There are, however, certain limitations of this work like absence of advanced technology, variation in the PCU values, time constraints. Nevertheless, this study will help the stakeholders in the construction sector to prioritise their resources towards factors which need to be improved to enhance the serviceability of the highway for present as well as for the future generation.

Developing Mixed Traffic Equivalency Factors to Estimate Saturation Flow at Urban Signalized Intersections

This study proposes a time occupancy approach to estimate passenger car units (PCUs) at urban signalized intersections with different interaction levels between vehicles under saturated green time conditions. The study shows a variation in PCUs with varied traffic and geometric conditions. Traffic data have been collected through videography techniques at signalized intersections in three metropolitan cities in India. Traffic flow discharge and clearance time of different vehicular categories have been extracted from the video during the saturated green time. The observed ranges of dynamic PCU values for two-wheelers, three-wheelers, big cars, light commercial vehicles, and heavy vehicles are 0.12 to 0.32, 0.45 to 0.80, 1.40 to 1.80, 1.60 to 2.20, and 3.50 to 6.50, respectively. Regression-based PCU models have been developed for each vehicle category to address the variation of individual vehicle PCUs with traffic compositions and flow rates. The model analysis shows that traffic compositions and flow rates are significantly affecting the PCU values. The PCU is a complex parameter requiring several field attributes. Therefore, to overcome the complexity of estimating PCUs, a concept of flow equivalency factor (FEF) has been proposed based on the estimated PCUs. The FEF can directly convert the mixed motorized vehicular flow into an equivalent standard passenger car flow without actually making use of different vehicles’ PCU factors. All the developed models have been validated for field conditions and results are found promising with field data. The developed approach can be used effectively for developing countries with a mixed traffic stream.

Determination of PCU values for mixed traffic conditions along the hilly road of East Sikkim

The road space in India is shared by different travel modes with different physical dimensions. On top of this, lane disciple is also not followed in India. All these factors influence the evaluation of traffic characteristics, roadway capacity, defining model for traffic flow and other transportation design factors. Passenger car unit (PCU) is a frequently used unit for calculating and expression of heterogeneous traffic volume to a simpler equivalent traffic unit where a passenger car is taken as a standard vehicle and all other classes of vehicle are expressed in terms of the standard car. For the present study, 11 km stretch of NH-10 in East Sikkim was taken into consideration. Data collection was done by video graphic survey. PCUs of different classes of vehicle are estimated using the speed area method by using traffic volume data. The PCU is calculated by multiplying the speed and area ratios of standard cars by the PCU of the subject vehicle type. The methodology adopted in this study is very much suitable for making proper PCU model under different conditions of heterogeneous traffic and road conditions of the study area..

Non-Linear Evaluation Model to Analyze Saturation Flow under Weak-Lane-Disciplined Mixed Traffic Stream

Saturation flow is an essential parameter for the performance evaluation and signal cycle design of an intersection. However, in a weak-lane-disciplined mixed traffic stream, vehicles (mainly motorized two- and three-wheelers) are more interested in forming queues with the behavior of creeping and infiltration through the larger vehicles for a quick dispersion. Consequently, a high rate of discharge can be found in the first few seconds of green, followed by a wavering discharge pattern to the end of the green period. In this context, the present study frames a non-linear evolutionary model (NLEM) to analyze passenger car unit (PCU) and saturation flow value by minimizing the vehicle encroachment and wavering in discharge for mixed traffic stream. Field traffic data was collected from 10 signalized intersections from three different cities of India. The NLEM considers the vehicle discharge during the saturated green interval in the optimization process to analyze PCU and saturation flow value. The result indicates an appropriate estimation of PCU and saturation flow concerning the Highway Capacity Manual. The discharge profile obtained using the proposed model also specifies the model’s aptness in analyzing the effect of vehicle encroachment and wavering throughout the green period. Thus, the proposed NLEM is probably suitable for analyzing the PCU and saturation flow of an intersection where vehicle interaction is sensitive because of a mixed scenario.

Estimation of Passenger Car Unit for Undivided Two-Lane Roads in the Mountainous Region

Indian traffic conditions consist of diverse vehicle categories of different static and dynamic properties, making it a heterogeneous flow. The vehicles' complex and dynamic behaviour can be dealt with by converting them into an equivalent passenger car unit (PCU). This study estimates the dynamic PCU values of vehicles in mixed flow conditions for undivided two-lane mountainous roads in India using the speed-area method. The vehicular dimensions and their operating speeds were considered as the prime factors for PCU estimation. The data collected from the sites located in the mountainous region of Himachal Pradesh was used to calculate the PCU value for different vehicles. When compared to the values provided in the Indian Highway Capacity Manual 2017, the PCU value of some vehicle categories was found to be different from the suggested range in the HCM. A variation in the PCU value was observed at different traffic flow, vehicular composition, and V/C ratio. This dependency of PCU values with these three parameters was analysed, and based on that, a set of mathematical models were developed. These models were further validated by statistical analysis with data collected at another study site with similar characteristics. As Indo-HCM 2017 suggests PCU values for plain terrain; these models can help forecast the vehicles' PCU values in the mountainous regions.

An optimised approach for saturation flow estimation of signalised intersections

Saturation flow is a fundamental performance measure parameter used for the design of intersections. However, in mixed traffic conditions, the evaluation of saturation flow is more sensitive due to heterogeneous traffic where vehicles are travelling in the same right of way without any lane separation. In such cases, the passenger car unit (PCU) plays a major role in analysing heterogeneity using an equivalent value for each vehicle. This paper presents a novel approach using the optimisation technique to determine PCU values and saturation flow for mixed traffic streams. Field data were collected at six signalised intersections in three Indian cities. The optimisation technique produced reasonable PCU values and an accurate estimation of saturation flow of 1906 PCUs/h. The saturation flow prediction model was developed using the multi-linear regression technique as per Pearson's correlation between saturation flow and vehicle compositional share. The developed saturation flow model was validated using field data from another site and the predicted value was in good agreement with the observed value. Finally, the predictive model was used to analyse the impact of traffic composition on saturation flow in mixed traffic streams.

WITHDRAWN: Effect of approach width on performance of signalized intersections

Saturation flow (SF) will be affected by the geometric, operating, traffic and environmental factors. This study analysis dealing with LOS at signalised intersections, effect of approach width on SF and passenger car units (PCU). Due to fundamental variations in traffic characteristics, the relations proposed by different ranchers to estimate the SF, initial time lost and PCU were not appropriate for heterogeneous conditions, due to variations in static and dynamic characteristics of vehicles with poor lane discipline. The main objective of the current research is to analyse the effect of approach width and right turning radies on SF and PCU, subsequently evaluated LOS under existing signal operating conditions. The data was collected at three signal controlled intersections in Visakhapatnam city and all the vehicles are categorized in to six classes. PCU values were estimated by taking small car as a standard vehicle by using Chandra’s formula. The relation of PCU value with approach width and turning radius is examined and represented graphically. PCU value has a linear relationship with approach width for through approaches. And PCU values of Right Turn (RT) vehicles are exponentially vary with RT radies. From the results observed that the other than two-wheeler remaining right turn vehicle, PCU’s are varies negative exponentially. LOS measured under existing fixed signal cycle time, mostly all the approaches were obtained LOS-D and only one approach of north bound of NAD intersection was obtained LOS-F. The LOS is assigned by using delay in sec., asper HCM-2010.

Determination of Passenger Car Unit for Urban Roads: A Case Study in Addis Ababa

In Ethiopia, specifically on Addis Ababa city roads operating, vehicles are mixed with varying static and dynamic traffic characteristics that are very challenging for the traffic analyst to come up with a sole solution to the traffic malady. Under heterogeneous traffic, each vehicle type cannot be compared with other vehicle types since it shows different effects on the road. It could be observed that the majority of the drivers in Addis Ababa road networks do not follow proper lane discipline to use any available space on the road sections. Currently, Ethiopia is using the passenger car unit values from other countries manual, which doesn't represent the local traffic and roadway conditions. This study was initiated to establish the PCU values that will cater the local settings. Hence, this study was focused on estimating the PCU values of multilane highways in Addis Ababa city and determining the influence of traffic volume and width of the road on the values of PCU. The PCUs were estimated for four vehicle types based on the variation of traffic volume and carriageway width. Dynamic PCU method was used to determine PCU values, and a linear regression analysis was performed for model development. The developed model is used to estimate PCU values having the same traffic conditions and roadway conditions found in other countries. The study results indicated that as the traffic volume and carriageway width increases, the passenger car unit value also increases. Also, it was found out that the results of PCU values in this study showed higher values than those provided in Highway Capacity Manual (HCM). Hence, the PCU values obtained are recommended to reflect the existing traffic condition in the locality.