Overview
Run-Off-Road (ROR) crashes are extremely severe road accidents that can often result in severe injuries or fatalities. The accident analysis conducted within the RISER project (and EU-funded project that concluded in 2006 highlighted that even though only 10% of the total accidents are single vehicle accidents (SVA, typically associated with ROR type accidents) the rate of SVA events increases to 45% when only fatal accidents are considered.
To reduce the severity of ROR crashes, “forgiving roadsides” need to be designed and this includes identifying where there is a need for a Vehicle Restraint System (VRS) and what appropriate VRS should be selected for specific location and traffic condition.
At the present time, whilst there are standards covering the testing, evaluation and classification of VRS within Europe (EN1317, EN12767, etc), their selection, location and installation are based upon national guidelines, often produced by National Road Authorities (NRA) and/or overseeing organisations. Due to local conditions, these national guidelines vary across Europe.
The aim of the SAVeRS (Selection of Appropriate Vehicle Restraint Systems) project is to produce a practical and readily understandable VRS guidance document and a user-friendly web-based tool that will allow the selection of the most appropriate solution in different road and traffic configurations for all types of VRS: safety barriers including parapets; crash cushions (including truck-mounted attenuators), terminals and transitions; motorcycle protection devices.
The guidance document and the web-based tool will have with the following goals:
- ensuring the safety of road users, road workers and third parties;
- optimising VRS performance in use;
- maximising VRS serviceable life;
- minimising VRS whole life costs.
The different solutions considered will be fully compatible with EN 1317 and related EN standards (for example the European passive safety standards EN12767, EN40 and EN12899).
An extensive analysis of existing national and international standards and guidelines will be carried out to identify, review and categorise information which is currently available in connection with the parameters associated with the choice of VRS. A data matrix will also be produced outlining, as a minimum, the type of variables (posted speed, AADT, etc) typically used for identifying the need for VRS in existing guidelines, the data available in NRA databases for the analyses and the previous studies linking variables and accident frequency/accident consequences. These variables will then be linked to the potential type and severity of collisions that can arise with a VRS, based on both existing studies and on additional crash data available for the SAVeRS project. Based on this information a practical guidance document and a web-based tool will then be produced which will include also life cycle cost models for VRS applications.
To ensure that the SAVeRS project output will be a useable, robust and realistic guidance tool to aid designers in their choice and selection of VRS, a specific evaluation Task will be performed to test the effectiveness of the guidelines and of the tool developed in the project The guideline and tool will be tested for application to new and current designs and against sites where VRS have been in use for some years and performance information is available.
Funding
Results
The final product of the SAVeRS project is the following set of documents that can be downloaded for the SAVeRS website (www.saversproject.com):
- Guideline for the selection of the most appropriate Roadside Vehicle Restraint System (this document);
- SAVeRS tool: an Excel spreadsheet with built-in macros where the models and selection criteria developed in the SAVeRS project and described in this Guide are implemented;
- SAVeRS tool user manual: a companion document that provides guidance for the use of the SAVeRS tool;
- Excel spreadsheet for the calibration of the crash prediction model for motorways (for users interested in calibrating the SAVeRS prediction model for a different motorway network);
- Excel spreadsheet for the calibration of the crash prediction model for two-lane twoways rural roads (for users interested in calibrating the SAVeRS prediction model for a different two-lane two-ways rural roads network).