Abstract

The EU-funded SafetyCube† project aims at facilitating decision making in road safety by providing systematically analysed and assessed scientific evidence on risk factors and countermeasures. While this is done for the areas infrastructure, vehicle and road users, this paper focus solely on the latter. The project outcomes are available online and are targeted at actual decision makers as well as researchers. Various stakeholders were consulted to identify hot topics and the needs of practitioners. The accessible database currently contains about 450 individual study outcomes and synopses with condensed information for 49 road risks (e.g. speeding, drink-driving, fatigue) and measures (fitness to drive, education, enforcement, campaigns, etc.) associated with all kinds of road users (vehicle drivers, cyclists, pedestrians, elderly, young, commercial drivers). In a further step, cost-benefit will be assessed on the basis of the effectiveness of countermeasures. While vehicle and infrastructure related risks and measures are well suited for effect quantification, this is a challenging endeavour for road users for many reasons.

Abstract

Introduction A prominent policy, which has been proposed in many European municipalities over the last years is the promotion of cycling to decrease pollution and to increase public health. One important part of the assessment of this policy is the estimation of the induced change in bicycle crash numbers. Several recent works supported the ideas by reporting that cycling becomes safer if the number of cyclists increases, i.e., there seems to be a safety-in-numbers effect (SiN). Methods The problems related to the interpretation of bicycle crash and volume data are discussed and an approach aiming at a better understanding of the SiN-phenomenon is presented. In particular it is proposed to adopt models with memory to pursue causal relations and to study SiN at different time scales. To estimate daily cyclist volumes from irregular counts, a weather based model for bicycle volumes is developed. Results We provide a proof of concept for the proposed memory model by testing it on synthesized data and apply the proposed techniques on data provided by Berlin authorities. The application on synthetic data shows that improved fits with memory models can indicate temporal correlations within data and, thus, can give hints for causal relations. Although such a temporal correlation could not be substantiated in the real data, a surprising ambiguity was found to exist on different time scales. Over the long term, individual risks decline with increased bicycle volumes, while on shorter terms the opposite seems to be present: The more bicyclists are on the roads, the more unsafe cycling becomes. Conclusions The paper concludes by considering possible interpretations for the observed ambiguity. Further, a discussion of the developed methodology and some thoughts for a role that the SiN effect can play for transportation planning are included. Document type: Article

Abstract

In 2003, Australian road transport jurisdictions collectively accepted that the greatest road safety gains would be achieved through adopting a Safe System approach, derived from Sweden's Vision Zero and the Netherlands' Sustainable Safety strategies. A key objective of all three approaches is to manage vehicles, the road infrastructure, speeds, road users and the interactions between these components, to ensure that in the event of crashes, crash energies will remain at levels that minimize the probability of death and serious injury. Older drivers pose a particular challenge to the Safe System approach, given particularly their greater physical frailty, their driving patterns and for some at least, their reduced fitness to drive. This paper has analyzed the so-called ‘older driver problem’ and identified a number of key factors underpinning their crash levels, for which countermeasures can be identified and implemented within a Safe System framework. The recommended countermeasures consist of: (1) safer roads, through a series of design improvements particularly governing urban intersections; (2) safer vehicles, through both the promotion of crashworthiness as a critical consideration when purchasing a vehicle and the wide use of developed and developing ITS technologies; (3) safer speeds especially at intersections; and (4) safer road users, through both improved assessment procedures to identify the minority of older drivers with reduced fitness to drive and educational efforts to encourage safer driving habits particularly but not only through self-regulation. Document type: Article

Abstract

Older drivers are frequently viewed as overly represented in crashes, particularly when crash involvement per distance travelled is considered. This perception has led to a call for tighter licensing conditions for older drivers, a policy which inevitably results in mobility restrictions for at least some drivers. However there is a growing body of research evidence which shows that as a group, older drivers represent no greater road risk than drivers from other age groups once different levels of driving activity are taken into account. This paper has examined aspects of older drivers' fitness to drive based on survey data and off-road and on-road driving performance from a sample of 905 New Zealand older drivers. The results show that policies which target all older drivers and lead to licensing and mobility restrictions cannot be justified from a safety basis. Document type: Article