General

This comprehensive empirical study investigates Vehicle Operating Costs (VOC) and urban traffic performance across the Metropolitan Area of Cape Town, South Africa. Urban transport networks present complex operating environments where traffic congestion, frequent signalized intersections, stop-and-go driving, and varying pavement conditions combine to elevate user costs. The study gathered extensive field data using telemetry-equipped commercial fleets, public transit buses, and private passenger vehicles operating along major arterial corridors and freeways. Empirical measurements focused on fuel consumption rates, tire wear, vehicle maintenance and repair expenses, and travel time delays under varying traffic densities and surface roughness levels. The report updates historical VOC baseline relationships, reflecting modern vehicle technologies, local fuel pricing, and current economic conditions in South Africa. Mathematical models were established linking speed-flow relationships and International Roughness Index (IRI) values to direct vehicle operating expenditures. The findings demonstrate that targeted pavement resurfacing and traffic signal optimization on high-volume urban corridors generate immediate, substantial economic savings for freight operators and commuters. The study provides Cape Town's transportation authority with recalibrated VOC parameters for use in traffic management models, public transport planning, and major infrastructure investment evaluations.

 

This research report published by Waka Kotahi NZ Transport Agency details the modern integration of vehicle operating cost (VOC) models with environmental emissions modeling frameworks for transport evaluation in New Zealand. As national policies emphasize carbon reduction and environmental sustainability alongside economic efficiency, traditional VOC appraisal tools must be updated to dynamically model fuel consumption, greenhouse gas (GHG) emissions (CO2, CH4, N2O), and airborne pollutants (PM2.5, NOx) across modern vehicle fleets. The study updates traditional HDM-4 vehicle operating cost algorithms to reflect New Zealand's evolving fleet profile, including hybrid, plug-in hybrid, and battery electric vehicles (EVs). It establishes integrated mathematical models that calculate energy consumption and emissions as functions of road geometry, gradient, surface roughness (IRI), speed variance, and congestion levels. Field validation using real-world driving data confirms that smoother road surfaces and optimized gradients yield measurable reductions in energy use and carbon output across both internal combustion and electric powertrains. The integrated model is incorporated into New Zealand's Monetised Benefits and Costs Manual (MBCM), providing transport planners with a unified analytical tool to evaluate the economic and environmental trade-offs of roading investments, pavement maintenance policies, and decarbonization strategies.

 

A dissertation presenting how EVs could be modelled with HDM-4. This shows the potential for major distortion of results as the capital costs are twice those with ICE vehicles.

This report details an empirical case study examining urban and corridor traffic congestion in India. The study quantifies peak-hour delays, travel time variability, and excessive fuel consumption across mixed traffic flows. Using field speed surveys and vehicle trajectory analysis, the paper establishes local congestion indexes, evaluates user cost surcharges, and provides strategic recommendations for traffic management and localized infrastructure improvements.

 

This report presents a critical literature review and comparative assessment of international and national traffic congestion metrics. The paper evaluates travel time reliability indices, congestion density ratios, and delay factors, recommending standardized measurement methodologies for application in Indian transport planning and engineering studies.

 

This study investigates how carriageway width variations, lateral clearances, and lane configurations affect traffic congestion levels on Indian highways. By measuring vehicle speeds and flow rates across varying cross-sectional geometries, the research provides empirical equations linking effective road width to corridor free speeds and bottleneck formation.

 

This paper provides a detailed structural analysis of traffic congestion dynamics on urban arterial corridors in India. Using micro-level traffic flow data and video trajectory analysis, the study explores bottleneck formation, shockwave propagation, and queue dissipation, establishing empirical models to estimate delay and operational inefficiency.

 

Detailed analysis of the total cost of ownership (TCO) consisting of all costs related to both purchasing and operating the vehicle. This TCO analysis builds on previous work to provide a comprehensive perspective of all relevant vehicle costs of ownership. In this report, we present what we believe to be the most comprehensive explicit financial analysis of the costs that will be incurred by a vehicle owner. This study considers vehicle cost and depreciation, financing, fuel costs, insurance costs, maintenance and repair costs, taxes and fees, and other operational costs to formulate a holistic total cost of ownership and operation of multiple different vehicles. For each of these cost parameters that together constitute a comprehensive TCO, extensive literature review and data analysis were performed to find representative values in order to build a holistic TCO for vehicles of all size classes. The light- and heavy-duty vehicles selected for analysis in this report are representative of those that are on the road today and expected to be available in the future. Table ES-1 summarizes the main parameters in this study, including the cost components which comprise TCO, the sizes and vocations of vehicles which are analyzed, the powertrains of these vehicles, and the model year for analysis of both current and future vehicles.

This comprehensive final report examines total cost of ownership (TCO) dynamics for electric vehicles (EVs) compared to internal combustion engine (ICE) vehicles in the United States. Covering purchase incentives, energy/charging costs, maintenance, insurance, and battery depreciation, the study provides robust empirical models for lifecycle economic comparisons across light-duty vehicle segments.

 

The HDM-4 Road User Costs Model (HDM-4 RUC) is an Excel based model designed to compute, for different vehicle types and road conditions, vehicle speeds, fuel consumption, vehicle operating costs, passenger time costs, emission and accident costs based on the Highway Development and Management Model (HDM-4) relationships. The model computes unit road user costs, performs sensitivity analysis, computes network road user costs and performs a simplified economic evaluation of a road project. The current version of HDM-4 RUC (Version 5.0) computes the vehicle operating costs and speeds, function of roughness, cubic polynomials that can be used together with the RED and RONET models.

This report evaluates the broader economic burden of urban traffic congestion in major Indian metropolitan regions. The study synthesizes direct user costs—such as excess fuel consumption and lost travel time—with macro-economic productivity impacts. The authors propose updated economic valuation models to assess the cost-benefit ratios of major urban bypasses and mass transport interventions.

 

Report on quantifying the input parameters, and indexes, for updating vehicle operating costs.

This paper presents a summary of findings on the effect of pavement roughness [international roughness index (IRI)] and texture [mean profile depth (MPD)] on vehicle operating costs. The most important cost affected by roughness was fuel consumption, followed by repair and maintenance, then tire wear. An increase in IRI of 1 m/km (63.4 in./mi) increased fuel consumption of passenger cars by 2% to 3%, regardless of speed. For heavy trucks, this increase was 1% to 2% at 70 mph and 2% to 3% at 35 mph. Surface texture and pavement type had no effect on fuel consumption for vehicle classes except heavy trucks. An increase in MPD of 1 mm (0.039 in.) increased fuel consumption by 1.5% at 55 mph and 2% at 35 mph. The effect of pavement type on fuel consumption was statistically not significant for all light vehicles and was statistically significant for heavy trucks only at 35 mph in summer conditions (308C). No data were available for heavy trucks in winter. For repair and maintenance, there was no effect of roughness up to an IRI of 3 m/km (190 in./mi). Beyond this range, an increase in IRI up to 4 m/km (254 in./mi) increased repair and maintenance costs by 10% for passenger cars and heavy trucks. At an IRI of 5 m/km (317 in./mi), the increase was up to 40% for passenger cars and 50% for heavy trucks. An increase in IRI of 1 m/km (63.4 in./ mi) increased tire wear of passenger cars and heavy trucks by 1% at 55 mph.

This research investigates the direct impacts of traffic congestion on total Vehicle Operating Costs (VOCs) and commuter travel time across Indian transport corridors. By measuring continuous fuel consumption variations during acceleration-deceleration cycles, the study derives updated delay penalty functions and operational cost factors for highway feasibility appraisals and road user cost assessments.

 

Updated vehicle operating cost (VOC) models are an important input to the economic evaluation of road projects. This paper presents revised VOC models for Australia updated as part of the National Guidelines for Transport System Management (NGTSM) review of parameter values. The paper first reviews the development of VOC models in Australia. It then outlines the methodology used to estimate revised rural (uninterrupted or free flow) models and urban (stop-start or interrupted flow) models. These are then available for modelling on the basis of different time periods, e.g. a.m. and p.m. peak periods, and day and night time off-peak periods, which provides a consistent approach to incorporating travel time and freight delay costs for general CBA with total RUC calculated using a common average travel speed/total link time. In the NGTSM, VOC models are specified for an extended set of 20 vehicle types, over different traffic and road conditions (using road roughness & speed as key variables depending on gradient, curvature and road width) and their basis and effect is illustrated herein. Payload is also incorporated into the models as a variable. Model coefficients have been re-estimated for the specified models, as well as outputs of the models in physical consumption units and monetary values for fuel consumption and for total VOC. Finally, the paper provides a set of recommendations for further development of VOC models in Australia.

Measurement of pavement permanent deformation is critical to highway agencies for both pavement design and rehabilitation. Since the AASHO Road Test in the late 1950s and early 1960s, field rut condition is monitored by agencies on a regular basis. Over the decades, rut depth has been the solely dominating pavement permanent deformation indicator extensively used, though it faces many criticisms for being incomplete to characterize rut. The premature data collection technology, lack of uniform practice standard, and unrealistic expectations have hindered the improvement of rut measurement.

Recently, two AASHTO draft standard documents PP70-10 and PP69-10 are published specifying data requirements and procedures for deriving new technical parameters, respectively. It is envisioned that the mature application of the 1 mm 3D pavement surface data collected by PaveVision3D Ultra system in companion with the new standards poses a significant opportunity to change the landscape of current rut measurement practice.

This research described in the thesis accomplishes the following tasks to provide substantial insights into the new rut measurement requirements. First, thirteen technical parameters covering multiple aspects of pavement ruts are derived based on PP69-10. The rut depth measures documented in PP69-10 are verified with ground truth values. Second, a thorough study of these rut attributes is conducted with 8,960 transverse profiles collected from National Highway Systems (NHS) in Arkansas. The interrelationships among different technical parameters are explored, and inferences regarding pavement performance are developed. Third, a comprehensive hierarchical system is constructed for overall permanent deformation evaluation. The standardized index provided by the proposed system can help highway agencies manage pavement performance in a more comprehensive and reasonable manner. Fourth, the impact of vehicle wandering on the accuracy of rut measurements is assessed. A methodology is developed and verified to reduce the adverse effect of unknown lane locations.

Overall, this thesis demonstrates findings of a timely study in rut measurement and characterization based on the latest standard protocols and data collection technology. The research provides insights and useful supplements to both practitioners and researchers in the transition to apply the most advanced 1 mm 3D laser imaging technology to comprehensive pavement survey.

The economic prosperity of a country is strongly associated with the relative size and physical condition of its road network, which is the most important component of its transportation infrastructure. The rate at which a country’s economy grows is very closely linked to the rate at which the transport sector grows. In the process of economic analysis of highways, the road user cost plays a significant role. Large research has been carried out in India, from half century. Amongst the Road User Cost (RUC) models, Vehicle Operating Cost (VOC) models are the major component and are analytically complex in nature. The determination of VOC is a key element in evaluating the highway projects. The updation of VOC models are required for highway project appraisals, particularly for road maintenance. The determination of VOC is complicated and time consuming, as lots of data collection is required. With time, these VOC models become outdated. In the current paper, another method, Whole price index was used to update the vehicle operating cost. This method is very simple, easy and time saving. This updated VOC models can be used by various Highway engineers to evaluate the road projects on monetary basis.

Paper from India listing RUE models and how they can be annually updated.

Engineering economic analysis applies economic concepts and methods to engineering problems to support decisions on a best course of action. Economic analysis provides a way of comparing the economic gains expected from an investment with the cost of that investment; providing an objective understanding of value to be expected for cost incurred. The Highway Development and Management Model (HDM-4) system is seen as the international standard decision support tool for road management. This article focuses on the Road User Cost Modelling in HDM-4 and validation of the model using Road User Costs Knowledge System (RUCKS).

Presentation summarizing current situation with regard to predicting vehicle operating costs

NHCRP 720. This report presents models for estimating the effects of pavement condition on vehicle operating costs. These models address fuel consumption, tire wear, and repair and maintenance costs and are presented as computational software on the accompanying CD-ROM

to facilitate use. The material contained in the report should be of immediate interest to state pavement, construction, and maintenance engineers; vehicle fleet managers; and those involved in pavement-investment decision processes and financial aspects of highway transportation.

This study presents the empirical development of congestion cost equations specifically calibrated for multilane highways operating under mixed traffic conditions in India. Mixed traffic environments, characterized by wide variations in vehicle speeds, sizes, and maneuverability (ranging from motorized two-wheelers and three-wheelers to heavy commercial vehicles), present unique modeling challenges compared to homogeneous traffic streams. The research utilizes extensive field data collected across primary arterial corridors, measuring volume-capacity ratios, free-flow speeds, travel time delays, and fuel consumption rates under varying traffic densities. By converting heterogeneous traffic streams into standard Passenger Car Units (PCUs) and analyzing speed-flow relationships, the authors derive explicit mathematical equations estimating additional economic costs incurred due to traffic congestion. These costs account for increased vehicle operating costs (VOC), extra fuel consumption, accelerated vehicle wear and tear, elevated tailpipe emissions, and travel time losses for passenger and freight transportation. The developed equations demonstrate how congestion costs escalate non-linearly as traffic demand approaches and exceeds highway capacity. The paper integrates these equations into economic appraisal frameworks, enabling transport planners to evaluate the feasibility of highway capacity expansion, lane additions, and access management projects. The findings provide transportation agencies in developing nations with essential parameters to quantify the economic drag of traffic congestion and prioritize infrastructure investments.

 

Report describing the effects of vehicle-generated dust.

This paper presents the development of empirical congestion cost equations specifically calibrated for multi-lane divided highways in India. Utilizing real-time vehicle performance metrics and travel-time delay surveys, the authors formulate speed-flow relationships and cost functions that capture the incremental economic penalties imposed by traffic congestion on heterogeneous traffic mixes.

 

Excel workbook for calculating the HDM-4 vehicle operating costs. Also includes a worksheet with values for HDM-4 user parameters applied in different countries.

[In Spanish] This paper aims to analyze the structure of the sub model Social and Environmental Effects (SEE), included in the version 1.3 of the Highway Development and Management System (HDM-4). Several studies have been carried out describing other sub models within the HDM-4 and regional experiences using this tool to manage road networks as well. Recently the Mexican Institute for Transportation (IMT) published a study concerning sensibility analysis of asphalt pavement deterioration model for Mexican conditions. However, this is the first attempt to analyse the potential use of the SEE in Mexico. Even though the SEE includes the analysis of the energy balance and the vehicle emissions, only the latter will be considered in this paper due to the lack of information concerning energy expenditures for relevant activities in Mexico. In spite of the fact that the model doesn?t provide accurate results because of the use of aggregated data and several simplifications in the model when representing the emission formation processes, it is concluded that the potential in the use of the SEE as an integral part of the HDM-4 is large, even more when the mechanisms and tools to calculate emissions from road transport are either too expensive or too complex to implement. It is also desirable to conduct other studies in order to calibrate the model, activity which requires a concerting effort from society, government and researchers due to the costs involved. Nevertheless, the benefits obtained could match or even surpass the costs, especially if externalities are taken into account.

[In Spanish] This paper aims to analyze the structure of the sub model Social and Environmental Effects (SEE), included in the version 1.3 of the Highway Development and Management System (HDM-4). Several studies have been carried out describing other sub models within the HDM-4 and regional experiences using this tool to manage road networks as well. Recently the Mexican Institute for Transportation (IMT) published a study concerning sensibility analysis of asphalt pavement deterioration model for Mexican conditions. However, this is the first attempt to analyse the potential use of the SEE in Mexico. Even though the SEE includes the analysis of the energy balance and the vehicle emissions, only the latter will be considered in this paper due to the lack of information concerning energy expenditures for relevant activities in Mexico. In spite of the fact that the model doesn?t provide accurate results because of the use of aggregated data and several simplifications in the model when representing the emission formation processes, it is concluded that the potential in the use of the SEE as an integral part of the HDM-4 is large, even more when the mechanisms and tools to calculate emissions from road transport are either too expensive or too complex to implement. It is also desirable to conduct other studies in order to calibrate the model, activity which requires a concerting effort from society, government and researchers due to the costs involved. Nevertheless, the benefits obtained could match or even surpass the costs, especially if externalities are taken into account.

PhD dissertation which provides background and enhancements to the HDM fuel and emissions modelling

Comprehensive book on RUE modelling

Paper summarising refinements and improvements to HDM-4 congestion modelling

Paper presented to PIARC on Japanese RUE calibration

HDM-RUE was developed to predict vehicle operating costs for economic analysis. It prepares tables of vehicle operating costs and contains many features not available in the HDM-4 software. The program was originally developed during the writing of the book 'Modelling Road User and Environmental Effects in HDM-4' but is now marketed commercially by HIMS Ltd. who purchased the IP.

HDM-RUE was developed to predict vehicle operating costs for economic analysis. It prepares tables of vehicle operating costs and contains many features not available in the HDM-4 software. The program was originally developed during the writing of the book 'Modelling Road User and Environmental Effects in HDM-4' but is now marketed commercially by HIMS Ltd. who purchased the IP.

HDM-RUE was developed to predict vehicle operating costs for economic analysis. It prepares tables of vehicle operating costs and contains many features not available in the HDM-4 software. The program was originally developed during the writing of the book 'Modelling Road User and Environmental Effects in HDM-4' but is now marketed commercially by HIMS Ltd. who purchased the IP.

The NZVOC Model is used by Transfund New Zealand to prepare tables of vehicle operating costs for their Project Evaluation Manual. Two projects were conducted to update the costs and develop a new version of the NZVOC Model, one in 1999 and a second in 2001-2003. The NZVOC model contains enhanced VOC relationships and formed the basis for the HDM-4 RUE model.

The NZVOC Model is used by Transfund New Zealand to prepare tables of vehicle operating costs for their Project Evaluation Manual. Two projects were conducted to update the costs and develop a new version of the NZVOC Model, one in 1999 and a second in 2001-2003. The NZVOC model contains enhanced VOC relationships and formed the basis for the HDM-4 RUE model.

The NZVOC Model is used by Transfund New Zealand to prepare tables of vehicle operating costs for their Project Evaluation Manual. Two projects were conducted to update the costs and develop a new version of the NZVOC Model, one in 1999 and a second in 2001-2003. The NZVOC model contains enhanced VOC relationships and formed the basis for the HDM-4 RUE model.

The NZVOC Model is used by Transfund New Zealand to prepare tables of vehicle operating costs for their Project Evaluation Manual. Two projects were conducted to update the costs and develop a new version of the NZVOC Model, one in 1999 and a second in 2001-2003. The NZVOC model contains enhanced VOC relationships and formed the basis for the HDM-4 RUE model.

This study presents a comprehensive economic analysis of road transport costs across primary arterial networks in Indonesia. The report examines component vehicle operating costs (VOC)—including fuel consumption, tire wear, vehicle maintenance, and depreciation—under varying road surface conditions (IRI) and topography. The findings establish baseline unit cost relationships and calibration parameters for network-level planning and highway appraisal models.

 

Report describing calibration and application of RUE models for New Zealand

Report reviewing VOC modelling against on-ground research

Report describing how standard VOC tables were prepared for the Transfund Project Evaluation Manual

Suite of applications by I. Greenwood of Opus International Consultants for calibrating and applying HDM, or other economic appraisal models. Includes the ability to predict the effects of congestion on fuel and tyres, work zone modelling, as well as calibrating specific modelling parameters.

Suite of applications by I. Greenwood of Opus International Consultants for calibrating and applying HDM, or other economic appraisal models. Includes the ability to predict the effects of congestion on fuel and tyres, work zone modelling, as well as calibrating specific modelling parameters.

Suite of applications by I. Greenwood of Opus International Consultants for calibrating and applying HDM, or other economic appraisal models. Includes the ability to predict the effects of congestion on fuel and tyres, work zone modelling, as well as calibrating specific modelling parameters.

Suite of applications by I. Greenwood of Opus International Consultants for calibrating and applying HDM, or other economic appraisal models. Includes the ability to predict the effects of congestion on fuel and tyres, work zone modelling, as well as calibrating specific modelling parameters.

ARRB testing of HDM-4's RUE modelling.

ARRB testing of HDM-4's RUE modelling.

HDM-4 RUE Model calibration done as part of the Gujarat State Highway Project

Article highlighting difference between the two sets of VOC models

ARRB plan for how to test HDM-4 for its introduction to Australia

HDM-4 RUE Model calibration done as part of the Thailand Central Database Project

Memo on issues with HDM emissions modelling

Report on framework for emissions modelling

ARRB testing of HDM-4's RUE modelling.

Briefing paper describing revised RUE model

Predicting road user costs for Thailand

Briefing paper describing RUE model

Paper summarizing road user effect modelling.

A review of how HDM-III was used in studies in different countries

Original report describing HDM-4 RUE models. Much of the work was subsequently updated but still provides good background information

A review of how HDM-III was used in studies in different countries.

How the recommendations from the workshop were implemented

Papers presented at workshop

A report on establishing VOC and pavement deterioration relationships for India. Contains a detailed review of the India VOC and PDWE research and how this work was used to establish models for use in the dTIMS PMS application.

The World Bank's Vehicle Operating Costs Model (HDM-VOC) is a stand alone program that estimates vehicle operating costs, using the HDM-III relationships, for ten vehicle types as a function of the vehicle characteristics, vehicle utilization, vehicle unit costs, and the road characteristics. The HDM-VOC software is available for downloading at this site, together with Technical Paper 234 'Estimating Vehicle Operating Costs' (PDF 3,336 KB) by Rodrigo S. Archondo-Callao and Asif Faiz..

Calibration and application of HDM-III for a feasibility study in Nepal.

How HDM-III was modified and calibrated to Myanmar for the Comprehensive Transport Study.

HDM-III reference manual Volume 4

HDM-III reference manual Volume 3

Early paper on the impact of roughness on vehicle operating costs.

One of the very early papers putting forward the integrated framework of considering road user costs in the planning of road investments.

Written by Jan de Weille, this is the foundational report for the World Bank\'s future efforts to develop HDM and other management systems. It describes the basis for quantifying road user costs as well as the early research that was available.