Martin van Maarseveen

A prototype fuel-efficiency support tool

An effective way to reduce fuel consumption in the short run is to induce a change in driver behaviour. If drivers are prepared to change their driving habits they can complete the same journeys within similar travel times, but using significantly less fuel. In this paper, a prototype fuel-efficiency support tool is presented which helps drivers make the necessary behavioural adjustments. The support tool includes a normative model that back-calculates the minimal fuel consumption for manoeuvres carried out. If actual fuel consumption deviates from this optimum, the support tool presents advice to the driver on how to change his or her behaviour. To take account of the temporal nature of the driving task, advice is generated at two levels: tactical and strategic. Evaluation of the new support tool by means of a driving simulator experiment revealed that drivers were able to reduce overall fuel consumption by 16% compared with ‘normal driving’. The same drivers were only able to achieve a reduction of 9% when asked to drive fuel efficiently without support; thus, the tool gave an additional reduction of 7%. Within a simulated urban environment, the additional reduction yielded by the support tool rose to 14%. The new support tool was also evaluated with regard to secondary effects.

THE EFFECTS OF AN EDGELINE ON SPEED AND LATERAL POSITION: A META-ANALYSIS

This paper presents a meta-analysis of studies that have evaluated the effects of an edgeline on speed and lateral position of motorised road users. Together with many other study characteristics, 41 estimates of the effects of an edgeline on speed and 65 on lateral position were extracted from the studies. The results of the evaluation studies show a great variety in effects. Both negative and positive effects on speed and lateral position were found; amongst others, increases in speed up to 10.6 km/h, as well as decreases in speed up to 5.0 km/h, and shifts of the lateral position towards the centre of the road up to 30 cm, as well as shifts towards the edge of the road up to 35 cm. Further analyses resulted in the determination of study characteristics that influence the effects of an edgeline on speed and lateral position. It is concluded that the effects of an edgeline on speed are related to the presence of a centreline. Applying an edgeline to a road without a centreline increases the speed of road users, and replacing a centreline by an edgeline decreases the speed. Results with respect to adding an edgeline to a road with a centreline were unclear. Another conclusion is that shoulder width and road environment contribute to the effects of an edgeline on lateral position. In combination with wide shoulders or buildings and/or trees next to the road, edgelines lead to shifts of the lateral position towards the edge of the road, and in combination with narrow shoulders or open fields, edgelines lead to shifts towards the centre of the road.

Do Calculated Conflicts in Microsimulation Model Predict Number of Crashes

A microsimulation model and its calculations are described, and the results that are subsequently used to determine indicators for traffic safety are presented. The method demonstrates which changes occur at the level of traffic flow (number of vehicles per section of road) and at the vehicle level (vehicles choosing different routes). The best-known safety indicator in this type of model is the conflict situation, in which two vehicles approach each other and, if no action is taken, a crash will occur. These conflict situations are detected in the simulation model. This method does not necessarily relate directly to any actual observed conflicts or recorded crashes. The quantitative relationship is examined between detected conflicts at junctions in the model and recorded crashes at the same locations in the real world. The methods chosen for detecting conflicts and for selecting crashes are explained. A microsimulation model was constructed for a regional road network. The conflicts in this network were detected, and the recorded crashes were selected. The results show a quantitative relationship between the number of conflicts at priority junctions and the number of passing motor vehicles on one hand and the number of observed crashes on the other hand. When crashes and conflicts are divided into crash categories, junctions with signals clearly show substantial differences between the relative numbers of frontal crashes and frontal conflicts.

Modeling Commuter Preferences for the Proposed Bus Rapid Transit in Dar-es-Salaam

The paper analyzes individual commuter preferences towards the proposed bus rapid transit (BRT) system in Dar-es-Salaam, Tanzania. The objective of the survey was to identify how commuters perceive and value the proposed BRT service quality attributes. A stated preference survey of potential users of the proposed BRT was administered to 684 commuters who traveled to the central business district (CBD) on a regular basis. To this end, a special pictorial score card was developed that was suited for the local context and needed to capture the preferences of the commuter respondents. The BRT attributes considered for study are travel time, travel fare, and comfort. The stated choice data were analyzed using a binary logit model. The findings reveal, in order of importance, that comfort is the most valued attribute compared to travel time and travel fare, respectively.

A Decision support system for preventive evacuation of people

As a densely populated country in a delta the Netherlands have to be very considered about flooding risks. Up to 65% of its surface is threatened by either sea or rivers. The Dutch government has started a research project ‘Floris’ (Flood Risk and Safety in the Netherlands) to calculate the risks of about half of the 53 dike-ring areas of The Netherlands. This project has four tracks: (1) determining the probability of flooding risks of dike-rings areas; (2) the reliability of hydraulic structures; (3) the consequences of flooding and (4) coping with uncertainties.

Urban growth and transport infrastructure interaction in Jeddah between 1980 and 2007

This paper aims to use spatial statistical tools to explore the reciprocal spatial–temporal effects of transport infrastructure and urban growth of Jeddah city, a fast developing polycentric city in Saudi Arabia. Global spatial autocorrelation (Morans I) and local indicators of spatial association (LISA) are first used to analyze the spatial–temporal clustering of urban growth and transport infrastructure from 1980 to 2007. Then, spatial regression analysis is conducted to investigate the mutual spatial–temporal effects of urban growth and transport infrastructure. Results indicate a significant positive global spatial autocorrelation of all defined variables between 1980 and 2007. LISA results also reveal a constant significant spatial association of transport infrastructure expansion and urban growth variables from 1980 to 2007. The results not only indicate a mutual spatial influence of transport infrastructure and urban growth but also reveal that spatial clustering of transport infrastructure seems to be influenced by other factors. This study shows that transport infrastructure is a constant and strong spatial influencing factor of urban growth in the polycentric urban structure that Jeddah has. Overall, this study demonstrates that exploratory spatial data analysis and spatial regression analysis are able to detect the spatial–temporal mutual effects of transport infrastructure and urban growth. Further studies on the reciprocal relationship between urban growth and transport infrastructure using the study approach for the case of monocentric urban structure cities are necessary and encouraged.

Comparison of Neural Networks and Gravity Models in Trip Distribution

Transportation engineers are commonly faced with the question of how to extract information from expensive and scarce field data. Modeling the distribution of trips between zones is complex and dependent on the quality and availability of field data. This research explores the performance of neural networks in trip distribution modeling and compares the results with commonly used doubly constrained gravity models. The approach differs from other research in several respects; the study is based on both synthetic data, varying in complexity, as well as real-world data. Furthermore, neural networks and gravity models are calibrated using different percentages of hold out data. Extensive statistical analyses are conducted to obtain necessary sample sizes for significant results. The results show that neural networks outperform gravity models when data are scarce in both synthesized as well as real-world cases. Sample size for statistically significant results is forty times lower for neural networks.

Method for Assessing Safety of Routes in a Road Network

In the Netherlands, the concept of sustainably safe traffic is the leading vision in road safety policy and research. The main goal of a sustainably safe road transport system is to reduce the annual number of road accident casualties to a fraction of the current levels. Important requirements resulting from this vision are that trips follow safe roads as much as possible, trips be as short as possible, and the quickest and safest routes coincide. Modeling route choice will provide answers to the planning issues of sustainably safe traffic; however, the safety effects of these requirements constitute a totally different issue, which needs to be dealt with. The focus of this study is on the design of a method that enables the planner to determine the safety effects of existing route choice and the changes in route choice. A description of road safety can be made in various ways. When a microscopic model is used, conflicts between vehicles will be an integral part of the simulation. The outcome will be used to compare the types of conflicts in a given simulation with the types of conflicts that would be acceptable in a sustainably safe road environment, for example, conflicts with opposing vehicles should be minimized at high speed differentials. A so-called route diagram of each route can be checked according to a series of criteria, each representing requirements for a sustainably safe route choice. Each criterion of the route diagram contributes to the total safety level of a route by the number of demerit points scored by the criterion. The criteria are described and tested in a microsimulation of alternative routes in a synthetic road network.

Environmental health related socio-spatial inequalities: identifying "hotspots" of environmental burdens and social vulnerability

Differential exposure to multiple environmental burdens and benefits and their distribution across a population with varying vulnerability can contribute heavily to health inequalities. Particularly relevant are areas with high cumulative burdens and high social vulnerability termed as “hotspots”. This paper develops an index-based approach to assess these multiple burdens and benefits in combination with vulnerability factors at detailed intra-urban level. The method is applied to the city of Dortmund, Germany. Using non-spatial and spatial methods we assessed inequalities and identified “hotspot” areas in the city. We found modest inequalities burdening higher vulnerable groups in Dortmund (CI = −0.020 at p < 0.05). At the detailed intra-urban level, however, inequalities showed strong geographical patterns. Large numbers of “hotspots” exist in the northern part of the city compared to the southern part. A holistic assessment, particularly at a detailed local level, considering both environmental burdens and benefits and their distribution across the population with the different vulnerability, is essential to inform environmental justice debates and to mobilize local stakeholders. Locating “hotspot” areas at this detailed spatial level can serve as a basis to develop interventions that target vulnerable groups to ensure a health conducive equal environment.

Older Adults' Outdoor Walking: Inequalities in Neighbourhood Safety, Pedestrian Infrastructure and Aesthetics

Older adults living in high-deprivation areas walk less than those living in low-deprivation areas. Previous research has shown that older adults’ outdoor walking levels are related to the neighbourhood built environment. This study examines inequalities in perceived built environment attributes (i.e., safety, pedestrian infrastructure and aesthetics) and their possible influences on disparities in older adults’ outdoor walking levels in low- and high-deprivation areas of Birmingham, United Kingdom. It applied a mixed-method approach, included 173 participants (65 years and over), used GPS technology to measure outdoor walking levels, used questionnaires (for all participants) and conducted walking interviews (with a sub-sample) to collect data on perceived neighbourhood built environment attributes. The results show inequalities in perceived neighbourhood safety, pedestrian infrastructure and aesthetics in high- versus low-deprivation areas and demonstrate that they may influence disparities in participants’ outdoor walking levels. Improvements of perceived neighbourhood safety, pedestrian infrastructure and aesthetic in high-deprivation areas are encouraged.