Abstract

This paper discusses possible contributions of psychologists to sustainable transportation. It is argued that in order to reach sustainable transportation, among others, behaviour changes of individual car users are needed. As transport policies will be more effective if they target important antecedents of travel behaviour, first, factors influencing such behaviour are discussed. It is argued that car use is very attractive and sometimes even necessary for many different reasons. This implies that a combination of policies is called for, each targeting different factors that support car use and hinder the use of more sustainable modes of transport. Next, the paper elaborates on policy strategies that may be employed to achieve sustainable transportation by changing car use. Increasing the attractiveness of sustainable transport modes by means of pull measures seems not sufficient to reduce the level of car use. Besides, car use should be made less attractive by means of push measures to force drivers to reconsider their travel behaviour. The acceptability of such policies may be increased by clearly communicating the aim of these policies, and the expected positive consequences (e.g., less congestion, improved environmental quality). Moreover, possible negative effects for individual freedom may be compensated by implementing additional policies aimed at facilitating the use of sustainable transport modes. Document type: Part of book or chapter of book

Abstract

This is a critique of ESARR4 and its main supporting documents. ESARR4 is the Eurocontrol Safety Regulatory Requirement Number 4 [Eurocontrol safety regulatory requirement ESARR4, Edition 1.0., Eurocontrol, Safety Regulation Commission, Brussels, 2001]: ‘Risk assessment and mitigation in ATM’, ATM standing for Air Traffic Management. It is demonstrated that ESARR4 and its supporting documents are defective. There is a lack of clarity about responsibilities for ATM safety. The claims ESARR4 etc. make for its proposed methodologies are overstated—not supported by sound evidence from real world hazard analysis. Serious negative effects from this defective document include mis-allocation of scarce safety resources and the diversion of attention away from real safety improvements—wasteful of regulators’ and managers’ time. Suggestions are made for repairing these deficiencies. The most important underlying change would be a refocusing on practical safety assessment based on methods that have already demonstrated their merits.

Abstract

The prime goal of the Air Traffic Management (ATM) system is to control accident risk. Some key questions are posed, including: What do design safety targets really mean and imply for risk modelling? In what circumstances can future accident risk really be modelled with sufficient precision? If risk cannot be estimated with precision, then how is safety to be assured with traffic growth and operational/technical changes? This paper endeavours to answer these questions by an analysis of the nature of accidents, causal factors and practical collision risk modelling. The main theme is how best to combine sound safety evidence and real world hazard analysis in a coherent and systematic framework.

Abstract

The increased availability of detailed trajectory data sets from naturalistic, observational, and simulation-based studies, is a key source for potential improvements in the development of detailed safety models that explicitly account for vehicle conflict interactions and various driving maneuvers. Despite the well-recognized research findings on both crash frequency estimation and traffic conflict analysis carried out over the last decades, only recently researchers have started to study and model the link between the two. This link is typically made by statistical association between aggregated conflicts and crashes, which still relies on crash data and ignores heterogeneity in the estimation procedure. More recently, an extreme value (EV) approach has been used to link the probability of a crash occurrence to the frequency of conflicts estimated from observed variability of crash proximity, using a probabilistic framework and without using crash records. In this study the Generalized Extreme Value distribution used in the block maxima (BM) approach and the Generalized Pareto Distribution used in the peak over threshold approach (POT), are tested and compared for the estimation of head-on collisions in passing maneuvers. The minimum time-to-collision with the opposite vehicle is used in both EV methods. Detailed trajectory data of the passing, passed and opposite vehicles from a fixed-based driving simulator experiment was used in this study. One hundred experienced drivers from different demographic strata participated in this experiment on a voluntary basis. Several two-lane rural highway layouts and traffic conditions were considered in the design of the driving simulator scenarios. Raw data was collected at a resolution of 0.1 s and included the longitudinal and lateral positions, speeds and accelerations of all vehicles in the scenario. From this raw data, both methods were tested for stationary and non-stationary models. The latter allowed not-only for a better modeling performance in estimating the number of expected crashes, but also for a quantified analysis of the detailed driving choices affecting the head-on crash probability during passing maneuvers. The estimation results showed that the BM approach yielded more stable results compared to the POT approach, but the latter was able to produce crash rate estimates more consistently sensitive to the covariates of interest. Finally, the estimated distributions were validated using a second set of data extracted from an additional driving simulator experiment. The results indicate that this is a promising approach for safety evaluation. On-going work of the authors will attempt to generalize this method to other safety measures related to passing maneuvers, test it for the detailed analysis of the effect of demographic factors on passing maneuvers' crash probability and for its usefulness in a traffic simulation environment.

Abstract

It is well known from the literature that road lighting has significant safety benefits. The NZTA Economic Evaluation Manual (EEM) quotes a 35% reduction in crashes as the effect of upgrading or improving lighting where lighting is poor.However, no well-established dose–response relationship to lighting parameters exists from which one can deduce benchmark levels of lighting for safety.This study looked at a sample of street lighting installations spread over the urban areas of nine territorial local authorities. Standard street lighting parameters were measured in the field using a variety of instruments including illuminance meter, luminance meter and digital camera. Field measurements were related to the ratio of night-time to day time crashes as a measure of night time safety vis-a-vis daytime safety.A statistically significant dose–response relationship was found between average road luminance and safety across all traffic volume groups, with an indication that the relationship may be stronger where more serious crashes are involved.Threshold increment was also a significant variable but not so longitudinal uniformity or overall uniformity.The results related to luminance will allow practitioners to better estimate the safety benefits of different levels of lighting resulting in better targeting of expenditure. Document type: Article

Abstract

Our transport system is not on a sustainable path. Achievements in terms of mobility have come at some considerable environmental, economic and social cost. Sustainability is a long-term concept, also demanding attention to its social dimension. For transport, this underscores a need to link considerations of the environment and traffic safety together. An integrated strategy implies systematic translation of a broad field of goals into a set of mutually reinforcing packages of measures. The focus is on improving the manner in which different actors recognise the need for co-operation and their readiness to implement it. The starting point is in improving communication. There are clear benefits in integration, in regard of both the synergy of actions as well as improved optimisation, but integration may also bring problems. This article is based on an international survey of an expert group formed by the OECD to review the issues and opportunities of integrating environmental and traffic safety strategies. The group assessed case studies from 12 countries and the European Union, using a classification scheme focusing on the decision contexts and life stages represented by the cases. The group's full report was published in 1997. In its conclusions, the group presents a pragmatic way ahead, and identifies some basic research needs. There are some important persisting questions: how to influence transport demand, how to increase the role of non-motorised traffic and public transport, how to find packages of measures relevant for entire regions surrounding large urban areas, and how to respond to the process of rapid motorisation in developing countries. There are as yet few measures dealing effectively with these issues, or taking them up with a concern for both safety and environment. While the approaches that have shown some success underline the importance of tailoring policies and strategies to the concrete situation of each country, they also demonstrate the importance of the international exchange of know-how. Document type: Article

Abstract

The occurrence of an incident is one of the main causes of traffic congestion and delay on urban freeways. Currently, the development of an efficient traffic incident management process is an emerging issue in intelligent transport systems. The focus of this study is to develop an incident response model for use in an incident management program designed to reduce incident related traffic congestion and delays. Establishing a fuzzy control system based on a real operation process of incident response would help decrease the workload of operators who are constantly making essential decisions, and would be helpful in developing a more reliable operation procedure. Traffic incident data obtained from traffic detectors and information systems on freeways should be considered in order to determine the best form of operation. In this study, a fuzzy incident response model is formulated in terms of incident, type of vehicle, type of incident vehicle, location of incident vehicle, and incident service time. In order to analyze the reliability of the proposed model, the application of the model is made using the actual incident data collected on the freeway in the Los Angeles area. The application of the model shows that the fuzzy incident response system is very effective in describing the actual judgment of the incident operators in terms of incident service time. Document type: Article

Abstract

We analyzed cognitive and physical changes in driving by aging drivers based on responses to a questionnaire delivered to elderly and non-elderly drivers in various regions of Japan. Factor analysis of the 27-item questionnaire indicated that four factors related to cognitive change while three factors related to driver physical change and task-oriented change. We adopted the situation awareness cognitive-behavioral model to examine relationships among derived factors. The four cognitive factors corresponded to the elements in the cognitive-behavioral process for automobile driving. The other three factors impact the cognitive-behavioral process. Investigation of the effects of demographic (age and area of residence) and automobile usage characteristics (driving frequency and annual mileage) on the factor scores revealed that cognitive and physical changes depended not only upon age but also on area of residence and automobile usage. From this results, daily driving experience was considered to influence cognitive and physical function. We analyzed the effect of cognitive and physical change on the level of satisfaction in using other modes of transportation from the perspective of elderly mobility. We found that drivers who scored higher for change in automobile driving skills remained satisfied with automobile use but not the use of public buses. Document type: Article

Abstract

Police based national accident data from the Netherlands show an enormous increase of both in number and in share of car rear-end collisions resulting in injury over the last 15 years. The average severity of those accidents remains low (illustrated by very low shares of occupants killed or hospitalised). However, the apparent increase in number of less severely injured as well as the personal and societal consequences of their injuries may well impose an increasing threat to the quality of life within the Dutch society. Based on national accident data as well as other relevant injury and traffic exposure data, the current situation in the Netherlands is described. Differences with respect to gender unexpectedly suggest that female drivers have a higher risk of their car being hit from behind than male drivers do. Less unexpectedly, differences are found between males and females with respect to injury susceptibility. These differences are analysed using controlling factors such as type of car, type of road, and exposure to traffic. It appears that not all of the indicators used point the same way; some of the increase mentioned may be due to registration biases. There is also a lack of adequate data with regard to the real number of whiplash injuries, their severity, and the longer-term consequences. Even if the total scope of the problem of whiplash injury in the Netherlands is still not fully known, the current estimate of societal consequences implicates a need for preventive measures. In the first place, accident prevention should be considered and a number of possible preventive measures (such as infrastructural improvement and application of ITS devices in cars to maintain distance in traffic) are discussed. Injury preventive measures (such as in car protection against whiplash) are already more generally available but still need much improvement. Document type: Article

Abstract

Bus travel in mixed traffic suffers from low speed and unreliability in Seoul. The Seoul Metropolitan Government has implemented a type of bus preferential treatment at most major arterials in Seoul since 1996. That is, the reserved bus lane designated for bus use only by land and pavement markings and signs, but not by fixed physical barriers. Until 1996 bus use the most predominant travel mode in Seoul, however the share of bus trips decreased remarkably from 1990 to 1997 due to the fast growing subway supply and the increased number of private vehicles. However, after the regular bus lanes were extended, the bus service improved and thus, the buses again became the predominant travel mode since 1998. In this paper, the performance impacts of reserved bus lanes in Seoul were evaluated and several suggestions for improving the effectiveness of the bus preferential treatment are proposed. The impacts of reserved bus lanes on both bus and auto performance were primarily measured by the relative speed changes of buses and autos and the average circulation rate of bus trips. Empirical results showed that the bus lanes were successful in improving average bus performance compared with other adjacent traffic. It was confirmed that right turning movement of the buses would cause the deterioration of bus speed in the curbside bus lanes. The average circulation rate of daily bus trips during the bus operation periods was somewhat increased by the bus lane introduction. A current warrant for reserved bus lanes in Korea was reviewed, and average bus speed during peak periods was proposed as a new warrant. In order to improve the effectiveness of the reserved bus lane, the type of lane markings in reserved bus lane, enforcement strategies for illegal parking in the bus lane and FIFO service at bus stops are discussed. Document type: Article