Interurban Road Research Articles

Traffic modelling in system boundary expansion of road pavement life cycle assessment

This paper uses a case study of a UK inter-urban road, to explore the impact of extending the system boundary of road pavement life cycle assessment (LCA) to include increased traffic emissions due to delays during maintenance. Some previous studies have attempted this but have been limited to hypothetical scenarios or simplified traffic modelling, with no validation or sensitivity analysis. In this study, micro-simulation modelling of traffic was used to estimate emissions caused by delays at road works, for several traffic management options. The emissions were compared to those created by the maintenance operation, estimated using an LCA model. In this case study, the extra traffic emissions caused by delays at road works are relatively small, compared to those from the maintenance process, except for hydrocarbon emissions. However, they are generally close to, or above, the materiality threshold recommended in PAS2050 for estimating carbon footprints, and reach 5–10% when traffic flow levels are increased (hypothetically) or when traffic management is imposed outside times of lowest traffic flow. It is recommended, therefore, that emissions due to traffic disruption at road works should be included within the system boundary of road pavement LCA and carbon footprint studies and should be considered in developing guidelines for environmental product declarations of road pavement maintenance products and services.

On interurban road pricing schemes and the impacts of traffic diversion on road safety in Germany: Empirical findings and implications

Recently, traffic diversion effects induced by tolling have increasingly been attracting attention, since interurban road charging schemes are becoming more widespread in Europe. However, less attention has been paid to unintended spillover effects concerning negative road safety outcomes, caused by traffic shifts to non-tolled adjacent secondary roads of inferior quality. This study introduces to the specifics of existing road pricing schemes in Europe, clarifies the characteristics of the German toll system and explores the relationship between toll implementation and road safety outcomes using regional German panel data for the period 2000-2010. To this end, we test different specifications using accident data, while controlling for transport-related and socioeconomic covariates. We find that the implementation of the heavy goods vehicle toll in 2005 has a negative impact on accident rates with damage to persons during our sample period. This finding is a valuable insight for policy makers, since the existence of a relationship between tolls, traffic diversion and road safety has important policy implications regarding the determination of optimal welfare-enhancing tolls.

Evaluation of pollutant loadings in highway runoff and relevant legislative framework

<div> <p>Non-point sources pollution from highway runoff is among the most important reasons for surface and ground waters degradation. Atmospheric deposition, exhaust emissions, pavement wear and tire wear all have been found to be crucial pollutants in highway runoff. The most critical pollutants included in the runoff of interurban roads such as total suspended solids, heavy metals, chlorides and nutrients, together with the factors affecting their concentration are been investigated. Existing legislation about drainage and highway stormwater management in United States and European Union as well as the federal agencies of the United States which have the responsibility to regulate drainage and stormwater management are also presented. Water pollution concerns in the Unites States are mainly addressed through the Federal Water Pollution Control Act of 1972, known as the Clean Water Act. Provisions within the Clean Water Act require all states to implement regulations in order to reduce the pollutant mass loading prior to discharging into water recipients. In European Union the Water Framework Directive 2000/60/EC sets common goals for the water management and created an overall water policy for management at an international level.</p> </div> <p> </p>

Supporting Sustainable Megaregion Development through Optimizing the Impacts of Transportation Investments

Transportation investments have profound indirect effects on urban development. Improving transportation infrastructure reduces travel times, and thus, enhances accessibility of the population to employment and vice versa. In this procedure, the cities whose accessibilities mostly benefit from the transportation improvements would attract more population and capital. This paper attempts to quantify these impacts in the megaregions, and to prioritize the transportation investments according to their potential effects on the sustainability of the future development in these regions. For this purpose, the problem is formulated as a bilevel programming model. At the upper level, subject to a budget and environmental constraints, the optimal subset of projects is chosen from the candidate set. The objective is to maximize the total production of the megaregion at the end of the planning horizon. The final product of each city is determined according to its resultant population and physical capital. Under the network investment decisions of the upper level problem, the lower level represents the route choice behavior of users. Because the focus of the study is interurban road networks, which have sparse connectivity, a simple all-or-nothing trip assignment technique is employed at this level. To illustrate the application of the proposed model, the Northeast Megaregion of the United States is used as the case study. The exact solution is obtained for this example and compared to the regional development without improving the transportation network.

Incorporating spatial equity into interurban road network design

Methods for the road network design problem, typically, are based on optimization of the network efficiency measures (e.g. network-wide travel time) under a predefined budget. In these approaches, equity issues are not taken into account and, consequently, most of the road improvements are planned next to large cities. Thus, disparities between large and small cities increase, which does not conform to sustainable development objectives. In this paper, to overcome concerns associated with traditional methods, equity is incorporated into the interurban road network design problem. To this end, accessibility concepts are employed. However, unlike previous studies, instead of maximizing the total accessibility, a new definition is proposed for inaccessibility, and total inaccessibility is minimized throughout the network. Using this new definition not only is more compatible with the equity issue, but also helps to eliminate the nonlinearity of the problem. Average travel time to neighboring opportunities is utilized to propose this definition for inaccessibility, which captures the reality more effectively. With the aim of this definition, equity is incorporated into the road network design problem implicitly. This is another improvement over previous methods, where a new term in the objective function or a new constraint is added to include the equity. The proposed model is formulated as a mixed integer linear programming (MILP) problem, where the objective is to minimize the aggregate inaccessibility over all the population centers in the network. To illustrate the application of the model, the Northwest region of the United States is used as the case study. The respective exact solution of the example is found using a commercial solver (CPLEX). This new solution is also compared with the solutions from the traditional methods.

Geo-Based Statistical Models for Vulnerability Prediction of Highway Network Segments

This study describes four statistical models—Poisson; Negative Binomial; Zero-Inflated Poisson; and Zero-Inflated Negative Binomial—which were devised in order to examine traffic accidents and estimate the best probability estimating model in terms of future risk assessment at interurban road sections. The study was conducted on four sets of fixed-length sections of the road network: 500, 750, 1000, and 1500 m. The contribution of transportation and spatial parameters as predictors of road accident rates was evaluated for all four data sets separately. In addition, the Empirical Bayes method was applied. This method uses historical accidents information, allowing regression to the mean phenomenon so as to improve model results. The study was performed using Geographic Information System (GIS) software. Other analyses, such as statistical analyses combined with spatial parameters, interactions, and examination of other geographical areas, were also performed. The results showed that the short road sections data sets of 500 and 750 m yielded the most stable models. This allows focused treatment on short sections of the road network as a way to save resources (enforcement; education and information; finance) and potentially gain maximum benefit at minimum investment. It was found that the significant parameters affecting accident rates are: curvature of the road section; the region and traffic volume. An interaction between the region and traffic volume was also found.

The Traffic Police Location and Schedule Assignment Problem

ABSTRACTThe traffic police routine patrol vehicle mission is to provide service to the public, primarily through enforcement of traffic laws and assistance to road users after accidents or other calls for service. An efficient traffic police location and schedule assignment (TPLSAP) across a road network ensures that the traffic police undertake their mission effectively. In the search for effective road network cover solutions, a multiple‐objective linear program is developed in the first stage with three distinct objectives. The objective functions maximize the following: (1) traffic police presence and conspicuousness; (2) police presence at blackspots where frequent traffic offences occur; and (3) the time available for proactive work. In the second stage of the TPLSAP formulation, distance and time halo effect integer linear programs produce a detailed, daily shift schedule across the planning horizon. Consequently, we formulate a routine traffic police schedule–location and activity problem, which incorporates road safety recommendations drawn from the literature, police policy and operational constraints. Finally, we apply the formulation to a case study of the interurban road network in Northern Israel, which highlights potential improvements over the current schedules. Copyright © 2014 John Wiley & Sons, Ltd.

The Stabilization of Weathered Dolerite Aggregates with Cement, Lime, and Lime Fly Ash for Pavement Construction

An experimental program was performed on weathered dolerite specimens stabilized by adding varying percentages of cement (4, 8, 12, and 16) % and lime (6 and 12) % and a combination of lime and fly ash (6% lime + 12% Fly ash and 12% lime + 12% Fly ash) % by dry weight of soil. The strength was examined under three different curing methods, namely, membrane curing (MBC), alternate moist-air curing (MAC), and water curing (WAC), by conducting unconfined compressive strength (UCS) tests. Simple polynomial and linear functions (regression models) were used to define the relationships between the variables investigated. Membrane curing (MBC) gave results close enough to the water curing (WAC) to indicate that it can be confidently used on the field during pavement construction. From the results obtained, for class B (interurban collector and major rural roads) pavement construction, addition of 8% cement was recommended for road base construction with stabilized WDA. Also the addition of 12 + 12% Lime and Fly Ash was recommended for road subbase construction with stabilized WDA. Stabilized WDA against the prejudiced myths would perform satisfactorily for base and subbase construction in both heavily trafficked and low volume roads with economic quantities of cement, lime, and fly ash in South Africa.

Calibration and Validation of Condition Indicator for Managing Urban Pavement Networks

Deterioration indexes that may combine types of surface distresses, serviceability, and structural indicators are commonly used for pavement management at the network level. These indexes differ in the types of deterioration and criteria considered to quantify severity and density of distresses. Most of these indexes were developed for interurban road networks; therefore, their application to urban networks is complex and not representative. For this reason, there is a need for a better understanding of urban pavement behavior to enable collection of the distresses relevant to these types of pavements and development of an overall condition index for urban pavements that represents the mix of the more relevant distresses for use in network analysis. This study is part of a 3-year project developed in Chile: Research and Development of Solutions for Urban Pavement Management in Chile. The main objective of this study was to calibrate and to validate an urban pavement condition index (UPCI) representative of the overall condition of these pavements, according to objective measures of surface distresses and evaluations of an expert panel. The scope of this study included the development of distress evaluation guidelines for asphalt and concrete pavements considering manual and automated surveys, the application of these guidelines in different types of urban networks, and the assessment of these networks by an expert panel. Finally, three UPCI equations were obtained with satisfactory validation for asphalt pavements with manual and automated data collection and for concrete pavements with manual data collection.

State of the Art of Slovenian Road Safety

The State of the Art of Slovenian Road Safety aims to provide a short description of road safety situation in Slovenia as well as to record all activities taken in Slovenia. This article is based on ROSEE ROad safety in South East European regions report. The road safety performance of Slovenia in comparison to other countries of South Eastern Europe is discussed. Basic road safety trends in Slovenia and a macroscopic analysis of road accident factors related to road users, road environment and vehicles are presented. Also the assessment of road safety legislation, policy and institutional capacity in Slovenia is undertaken. In this article, the assessment of needs and availability of road safety related data and information in Slovenia is also presented. Finally, the road network conditions in Slovenia, a general road safety assessment of the interurban road network and the status of Road Safety Audits are described.

Water bodies pollution due to stormwater runoff in highways: measures and legislative framework

Nowadays, it is a common ascertainment that stormwater runoff in the urban and interurban road network consist non-point source pollution which contributes to the degrading of the quality of water of ground and surface water bodies. Taking into account the fact that water pollution has impacts to people and also to flora and fauna, the need to take measures in order to confront this environmental problem becomes inevitable. The adverse impacts of the stormwater runoff can be minimized with structural and non-structural Best Management Practices (BMPs) or with a combination of them. Within the content of the present paper the following are included: a) the investigation and presentation of the receiving waters pollution issues from the highway road network stormwater runoff together with the European transport policy concerning the development of an integrated highway road network, b) the examination of the respective pollutant generation and characteristics, c) the presentation of their impacts, d) the examination of the measures (structural and nonstructural BMPs), e) the presentation of the “first flush” phenomenon, f) The presentation of the existing legislation in the EU with emphasis in the E.U. Directive 2000/60/EC as well as the presentation of the relevant existing environmental legislation in Greece, including also the presentation of the way the Highway Guidelines actually deal with the specific problem.

Improving the analysis of road pricing acceptability surveys by using hybrid models

Several international studies have analyzed the acceptability of road pricing schemes by means of an attitude survey in combination with the results of a stated choice experiment using both a descriptive analysis and a discrete-choice model with binary choice (“accept” or “not accept” the toll). However, the use of hybrid discrete choice models constitutes an innovative alternative for integrating subjective attitudes and perceptions deriving from the survey of attitudes with the more objective variables from the stated choice experiment. This paper analyzes the results of applying these models to measure the acceptability of interurban road pricing among different groups of stakeholders (road freight and passenger operators, highway concessionaires, and associations of private car users) with qualitatively significant opinions on road pricing measures. Our results show that hybrid models are better suited to explaining the acceptability of a road pricing scheme by different groups of stakeholders than a separate analysis of the survey of attitudes and a discrete-choice model applied on a stated choice experiment. A particular finding was that the strong psycho-social latent variable of the perception of fairness explains the rejection or acceptance of a toll scheme by road stakeholders.

Interurban collective transport and road crashes in Santiago, Cape Verde

Based on research first begun in Praia (capital of Cape Verde) into the new public organization of its streets and squares – increasingly occupied by cars and other types of motor vehicles –, this article develops a description of the social universe of private group transport on the island of Santiago, and analyses its relationship with road crashes. Its chief focus is the hiace, a generic term designating transportation vans in Cape Verdean society (although they are named after the Hiace model manufactured by Toyota, in this research the word is used as an emic concept). Thus, through the field work completed to date, it outlines the social processes and dimensions in which road crashes involving hiaces take place. Moreover, it puts forward some comprehensive explanations of the causes for the island’s high road accident rate within the context of the urban transformation processes underway there. It furthermore reflects on the antagonistic experiences caused by the use of space by both motor vehicle drivers and the pedestrians themselves – space being understood as a social process – in relation to the living conditions and different experiences of the people of Cape Verde.

Location-allocation models for traffic police patrol vehicles on an interurban network

This research investigates the traffic police routine patrol vehicle (RPV) assignment problem on an interurban road network through a series of integer linear programs. The traffic police RPV’s main task, like other emergency services, is to handle calls-for-service. Emergency services allocation models are generally based on the shortest path algorithm however, the traffic police RPV also handles other roles, namely patrolling to create a presence that acts as a deterrence, and issuing tickets to offenders. The RPVs need to be located dynamically on both hazardous sections and on roads with heavy traffic in order to increase their presence and conspicuousness, in an attempt to prevent or reduce traffic offences, road accidents and traffic congestion. Due to the importance of the traffic patrol vehicle’s location with regard to their additional roles, allocation of the RPVs adheres to an exogenous, legal, time-to-arrival constraint. We develop location-allocation models and apply them to a case study of the road network in northern Israel. The results of the four models are compared to each other and in relation to the current chosen locations. The multiple formulations provide alternatives that jointly account for road safety and policing objectives which aid decision-makers in the selection of their preferred RPV assignments. The results of the models present a location-allocation configuration per RPV per shift with full call-for-service coverage whilst maximizing police presence and conspicuousness as a proxy for road safety.

Road safety performance indicators for the interurban road network

Various road safety performance indicators (SPIs) have been proposed for different road safety research areas, mainly as regards driver behaviour (e.g. seat belt use, alcohol, drugs, etc.) and vehicles (e.g. passive safety); however, no SPIs for the road network and design have been developed. The objective of this research is the development of an SPI for the road network, to be used as a benchmark for cross-region comparisons. The developed SPI essentially makes a comparison of the existing road network to the theoretically required one, defined as one which meets some minimum requirements with respect to road safety. This paper presents a theoretical concept for the determination of this SPI as well as a translation of this theory into a practical method. Also, the method is applied in a number of pilot countries namely the Netherlands, Portugal, Greece and Israel. The results show that the SPI could be efficiently calculated in all countries, despite some differences in the data sources. In general, the calculated overall SPI scores were realistic and ranged from 81 to 94%, with the exception of Greece where the SPI was relatively lower (67%). However, the SPI should be considered as a first attempt to determine the safety level of the road network. The proposed method has some limitations and could be further improved. The paper presents directions for further research to further develop the SPI.

ENERGY CONSUMPTION AND EMISSIONS FROM THE ROAD TRANSPORT IN SPAIN: A CONCEPTUAL APPROACH

The interurban road transport is one of the largest sources of emissions within all the economical sectors of Spain and accounts for 30% of the total energy consumption and subsequent CO2emissions. Fuel consumption, mostly gasoline and diesel, has decreased by −0.7% between 2004 and 2009 despite the increase of vehicle fleet (14.7%) and related travelled performances (3.1%). The paper estimates the energy consumption and subsequent emissions of CO2 and pollutants, CO, NOx, PM and NMVOC, of the interurban road transport in Spain for the period 2004–2009 by the use of a conceptual procedure. This procedure makes an effort to allocate the fuel sales, liters of diesel and gasoline, across different categories of vehicles (ages and technologies) operating on the interurban Spanish roads. In order to elaborate the inventory of energy consumption and emissions, the procedure uses the emission factors from the Copert process-based model, optimized for the Spanish interurban driving conditions. According to the inventory, total CO2 emissions have decreased from 68.0 Mt of CO2in 2004 to 66.9 Mt (−1.6%). This trend is due to diesel road vehicles. The CO2 emissions of gasoline vehicles and the total emission of related pollutants followed a downward trend due to technological improvements of vehicles and decrease of gasoline consumption. The CO2 emissions of diesel vehicles and the total emission of related pollutants followed an upward trend due to the increase of diesel consumption despite technological improvements of vehicles. Better estimates of energy consumption and emissions are possible in the future by using specific emission factors for different vehicle categories based on telemetric systems.

Improving road-side surveys for a better knowledge of road freight transport

The focus of this paper is to enhance our observation and knowledge of interurban road freight transport. It explores some possibilities for improving roadside freight surveys, usually used to gather origin-destination data. To achieve this, new questions are added to a standard roadside survey form, and the enhanced survey form is tested through two surveys. The new questions relate to currently unobserved variables: the vehicle volume occupied by freight; the method of organisation (double crew, relays) used by the carriers; the existence of specific logistical imperatives; and drivers’ compulsory breaks. The questions on volume constraint and carrier organisation prove to be the most informative. These two questions are thus two promising areas for improvement in roadside freight surveys. The questions about specific logistical imperatives and driver breaks prove less fruitful. The paper concludes that it is possible, through minor modifications in data collection protocols, to significantly enhance observation quality in road freight transport activity.

Sustainable and efficient interurban public road transport in Hungary

Buses are characteristic for Hungarian interurban traffic. This paper has the key objectives of determining the economically feasible point of reselling the buses. The paper is based on Hungarian data. The paper highlights the importance of operation of public transport vehicles and the optimum solution for minimizing their costs. Hungarian operators try to achieve this goal, although this is not easy due to their limited resources. Because of the present national economic situation in Hungary buses are operated much longer than it would be economically beneficial. Unfortunately the acquisition of newer buses is a slow process. All these problems significantly increase the losses of our interurban public transport companies.

Hazard perception at high- and low-risk road sites: a pilot study of interurban roads in Pakistan and Cameroon

ObjectivesInterurban roads account for a significant proportion of traffic deaths in developing countries. In this pilot study, hazard perceptions of interurban road sites involved in ≥3 injury road traffic crashes...

P2-543 Mortality from road traffic injuries in Cameroon: the neglected epidemic

ObjectiveDeveloping countries are experiencing the highest burden of road traffic injuries (RTI) with more than 85% of road traffic deaths worldwide. Epidemiologic data are scarce in sub Saharan Africa to...