No abstract

Standing in cost-benefit analysis of road safety measures:A case of speed enforcement vs. speed change

Tunnels within primary road networks are complex systems. The prerequisite of a good level of service is the seamless interaction of the various tunnel components (structural elements and technical equipment). Due to their heterogeneous nature, electrical and structural components are subject to divergent aging processes which require recurring maintenance procedures and rehabilitation measures. Considering the diversity of specifications and requirements among electrical/mechanical and structural components, it is evident that there is a considerable mismatch of maintenance cycles among them. Hence, tunnel asset management faces the challenge to develop strategies to integrate both the necessary functional integrity of the individual components over their respective lifecycle and the requirement of an optimized management for the overall system. Yet, the synchronization of measures towards maximizing system availability must not contradict positive wear‐and‐tear contingencies of the various tunnel components. Evidence based forecasting and reliability centred decision models are key elements of modern life cycle management. They must include interdependencies between the diversity of components and their manifold maintenance cycles.

Run-off-road (ROR) crashes are extremely severe road accidents that often result in serious injuries or fatalities. On Austrian motorways, about 40% of all injury accidents are ROR crashes, which account for more than 60% of the fatalities on the primary road network. This is one of the reasons why the Austrian highway operator (ASFINAG) postulates in its road safety program till 2020 that new safety strategies and new road safety measures have to be developed to prevent vehicles from running off the road and (in a worst case scenario) collide with stationary obstacles on the roadside. RISKANT is a research project funded within the 2011 Call "Transportation Infrastructure Research (VIF)" of the Austrian Research Promotion Agency (FFG) in conjunction with ASFINAG. The main objective of RISKANT was to develop a risk model for crashes with stationary obstacles along the roadside. In order to achieve this goal, a so-called accident prediction model was used to estimate the probabilities of ROR crashes due to the characteristics of the road and the road environment. Furthermore, Finite element simulation studies were conducted to incorporate the severity of injuries due to collisions with different stationary obstacles. Two indices, the Acceleration Severity Index (ASI) and Theoretical Head Impact Velocity (THIV) were used to evaluate the injury risk level for vehicle occupants.

collisions between vehicles leaving the road and unforgiving roadside objects such as trees, poles, road signs, etc. constitute a major road safety issue. On the Austrian road network, approximately 7.500 injury crashes occur every year due to run-off-road (rOr) manoeuvres (i.e. 20% of all injury crashes on public roads), contributing 35% to fatalities and 25% to serious injuries. Vehicle restraint systems (VrS) such as guardrails, concrete barriers, terminals or crash attenuators play a decisive role in mitigating the consequences of rOr crashes. unfortunately, most national road administrations (NrA) do not have a centralized data management, while geo-referenced information on VrS and their safety-related attributes are also not available as digitized data. researchers from the AIT have developed a novel approach to investigate, classify and evaluate VrS by means of image data processing, towards providing a comprehensive VrS inventory. The information obtained can be used for benefit-cost-analyses, road safety inspections and the evaluation of the effectiveness of different vehicle restraint systems.