A sketch planning methodology for determining interventions for bicycle and pedestrian crashes: an ecological approach

Bicycle and pedestrian safety planning have recently been gaining increased attention. With this focus, however, comes increased responsibilities for planning agencies and organizations tasked with evaluating and selecting safety interventions, a potentially arduous task given limited staff and resources. This study presents a sketch planning framework based on ecological factors that attempts to provide an efficient and effective method of selecting appropriate intervention measures. A Chicago case study is used to demonstrate how such a method may be applied

Do more trucks lead to more motor vehicle fatalities in European roads? Evaluating the impact of specific safety strategies.

Truck operations have recently become an important focus of academic research not only because road freight transport is a key part of logistics, but because trucks are usually associated with negative externalities including pollution, congestion and traffic accidents. While the negative environmental impacts of truck activities have been extensively analyzed, comparatively little attention has been paid to the role of trucks in road accidents. A review of the literature identifies various truck-traffic safety related issues: frequency of accidents and their determinants; risk factors associated with truck driver behavior (including cell phone use, fatigue, alcohol and drugs consumption); truck characteristics and facilities (roadway types, specific lanes and electronic stability programs) to improve performance of vehiclemaneuvering; and the safety characteristics of heavy and large trucks. However, to date, there seems to have been developed few studies evaluating the complex coexistence of trucks and cars on roads and that may support the implementation of differential road safety strategies applied to them. This paper focuses on the impact on the traffic fatalities rate of the interaction between trucks and cars on roads. We also assess the efficiency of two stricter road safety regulations for trucks, as yet not harmonized in the European Union; namely, speed limits and maximum blood alcohol concentration rates. For this, econometric models have been developed from a panel data set for European Union during the years 1999–2010. Our findings show that rising motorization rates for trucks lead to higher traffic fatalities, while rising motorization rates for cars do not. These effects remain constant across Europe, even in the most highly developed countries boasting the best highway networks. Furthermore, we also find that lower maximum speed limits for trucks are effective and maximum blood alcohol concentration rates for professional drivers are only effective when they are strictly set to zero. Therefore, our results point to that the differential treatment of trucks is not only adequate for mitigating an important source of congestion and pollution, but that the implementation of stricter road safety measures in European countries for the case of trucks also contributes significantly to reducing fatalities. In summary, and as a counterpoint to the negative impact of trucks on road traffic accidents, we conclude the effectiveness of efforts made in road safety policy (based on specific traffic regulations by vehicle type imposed by member States) to counteract the safety externalities of freight transportation in the European Union. In certain sense, our study might provide indirect support to public policies implemented at the macro European level to promote multimodal transport corridors. In this respect, there is an increasing focus at the European level on how freight transport can be moved from trucks on roads to more environmentally-sustainable modes, such as rail and ship.Dirección General de Tráfico SPIP2014127

A decision support system based on Electre III for safety analysis in a suburban road network

The aim of this paper is to develop a method for supporting decision makers in transport planning. When funds are insufficient to cover the interventions required to ensure safe driving conditions, it is necessary to optimize resources for the most critical sections. In this analysis, the multicriteria ranking method based on the ELECTRE III algorithms is applied to a real case, involving different sections of a motorway. This analysis is based on a comparison of different road sections in regard to safety conditions. The rank of more critical sections identifies intervention priorities

Effects of Transit Signal Priority on Traffic Safety: Interrupted Time Series Analysis of Portland, Oregon, Implementations

Transit signal priority (TSP) has been implemented to transit systems in many cities of the United States. In evaluating TSP systems, more attention has been given to its operational effects than to its safety effects. Existing studies assessing safety effects of TSP reported mixed results, indicating that the safety effects of TSP vary in different contexts. In this study, TSP implementations in Portland, Oregon, were assessed using interrupted time series analysis (ITSA) on month-to-month changes in number of crashes from January 1995 to December 2010. Single-group and controlled ITSA were conducted for all crashes, property-damage-only crashes, fatal and injury crashes, pedestrian-involved crashes, and bike-involved crashes. Evaluation of the post-intervention period (2003 to 2010) showed a reduction in all crashes on street sections with TSP (-4.5 percent), comparing with the counterfactual estimations based on the control group data. The reduction in property-damage-only crashes (-10.0 percent) contributed the most to the overall reduction. Fatal and injury crashes leveled out after TSP implementation but did not change significantly comparing with the control group. Pedestrian and bike-involved crashes were found to increase in the post-intervention period with TSP, comparing with the control group. Potential reasons to these TSP effects on traffic safety were discussed.Comment: Published in Accident Analysis & Preventio

A decision support system for road safety analysis

The aim of this paper is to develop a procedure for supporting public administrations in planning safety interventions on the road network. Road safety conditions depend on several factors, represented by a variety of quantitative and qualitative data, including: number of traffic accidents, traffic flow, lane width, shoulder width, road curvature and grade, access-point density, road markings and road signs (Mooren et al., 2012; OECD, 2002). By analysing a set of given roads or different sections of the same road, each with specific safety conditions, this methodology allows to determine which sections require interventions to improve safe driving conditions. Specifically, the multicriteria analysis technique is used in decision-making processes to support the choice among different alternatives in complex problems (Fadda, 2002). Among the different multicriteria techniques available, the Concordance Analysis will be used here. This paper proposes a unique modelling tool that incorporates the different indicators to calculate safety conditions. The methodology has been applied to a real case study for evaluating road safety on sections of a motorway infrastructur

Network effects of intelligent speed adaptation systems

Intelligent Speed Adaptation (ISA) systems use in-vehicle electronic devices to enable the speed of vehicles to be regulated externally. They are increasingly appreciated as a flexible method for speed management and control, particularly in urban areas. On-road trials using a small numbers of ISA equipped vehicles have been carried out in Sweden, the Netherlands, Spain and the UK. This paper describes the developments made to enhance a traffic microsimulation model in order to represent ISA implemented across a network and their impact on the networks. The simulation modelling of the control system is carried out on a real-world urban network, and the impacts on traffic congestion, speed distribution and the environment assessed. The results show that ISA systems are more effective in less congested traffic conditions. Momentary high speeds in traffic are effectively suppressed, resulting in a reduction in speed variation which is likely to have a positive impact on safety. Whilst ISA reduces excessive traffic speeds in the network, it does not affect average journey times. In particular, the total vehicle-hours travelling at speeds below 10 km/hr have not changed, indicating that the speed control had not induced more slow-moving queues to the network. A significant, eight percent, reduction in fuel consumption was found with full ISA penetration. These results are in accordance with those from field trials and they provide the basis for cost-benefit analyses on introducing ISA into the vehicle fleet. Contrary to earlier findings from the Swedish ISA road trials, these network simulations showed that ISA had no significant effect on emission of gaseous pollutants CO, NOx and HC. Further research is planned to investigate the impact on emission with a more comprehensive and up to date modal emission factor database

How to monitor sustainable mobility in cities? Literature review in the frame of creating a set of sustainable mobility indicators

The role of sustainable mobility and its impact on society and the environment is evident and recognized worldwide. Nevertheless, although there is a growing number of measures and projects that deal with sustainable mobility issues, it is not so easy to compare their results and, so far, there is no globally applicable set of tools and indicators that ensure holistic evaluation and facilitate replicability of the best practices. In this paper, based on the extensive literature review, we give a systematic overview of relevant and scientifically sound indicators that cover different aspects of sustainable mobility that are applicable in different social and economic contexts around the world. Overall, 22 sustainable mobility indicators have been selected and an overview of the applied measures described across the literature review has been presented

How Should We Prioritise Incident Management Deployment?

With perpetual strains on resources and traffic increasing at a steady rate, transport agencies need to evaluate the road network and make informed decisions to determine which roads have the greatest risk of adverse impacts and therefore identify the roads that have the greatest case for intervention. This is especially the case for Intelligent Transport Systems (ITS) and in particular incident management services where decision-making techniques are immature relative to conventional road engineering. This problem is compounded by the fact that common evaluation tools are insufficient for ITS applications. Historical information for ITS impacts is not always readily available, impacts are not transferable and impacts are incremental to the individual user. For these reasons, a new network evaluation framework is presented in this paper for incident management deployment. The framework aims to analyse the road network and prioritise roads with respect to two factors: the historical risk associated with incidents; and the cost effectiveness of implementation. To assess the historical risk, the framework initially converts social, economic and environmental impacts to a common monetary base, enabling the addition of the incident impacts. The economic impact values must be treated as relative values of measurement, not absolute costs. The second part of the framework assesses the historical risk, taking into account both the consequence of an event, measured in economic terms described above, and the probability of an event occurring based on historical information. The third uses a cost-effective ratio comparing the reduced impacts with the project costs. The economic risk analysis presented in Figure 1 below integrates safety, reliability and environmental impacts, providing an integrated decision-making tool for proactive ITS deployment decision-making