Overview
The level of road safety for the Trans-European Roadway Network (TERN) that links major European centres is, to a large extent, determined by features and design of the road transport infrastructure. Road design is
understood to be a complex task which requires different skills, such as principal traffic engineering techniques, knowledge about driver behaviour and consistency with an underlying design philosophy. In the past, most road design philosophies have been based on a mix of best practice and research findings in the field. Explicit design strategies combining the idea of a 'sustainable, safe traffic and transport system' with the technical goal of 'relation design' are anticipated to improve the soundness and safety of future road design.
SAFESTAR aimed to gain more in-depth knowledge about the underlying principles of road planning and design in order to carry out an effective safety policy at the European level.
The main objectives of SAFESTAR were:
- The main objectives of SAFESTAR were: to select an advanced tunnel design, that would be tested in a driving simulator;
- to survey the dangers of so-called express roads and to provide recommendations for their future design;
- to evaluate the differences in cross-sections based on the evaluation of accident characteristics, and to select promising corrective measures;
- to increase knowledge about the design of curves for rural roads and its impact on safety, based on the evaluation of speed profiles and accident frequency;
- to improve calculation models used to predict accident levels for newly built junctions; and
- to perform safety audits in order to assess pre-construction safety levels in road design, evaluating several design procedures in different countries.
Funding
Results
SAFESTAR has:
- proposed advanced design standards for motorways comprising
- obstacle-free zones of at least 9 metres on each side of the road, and inclines within these obstacle-free zones not being steeper than 20%,
- median strips having a width of at least 20 m except where protective barriers are used,
- increased width of emergency lanes and better lighting,
- consistent road layout in tunnels avoiding to negatively influence drivers' choice of speed, and sufficient unobstructed view (at least 100 m) of exits and entries in tunnels;
- proposed design principles for express roads comprising
- the restricted application to high-speed motorised traffic and limited numbers of exits,
- forward visibility never being less than the safe stopping distance of a car,
- lane widths on both single and dual lane roads of 3.5 m and cross sections including a continuation of the paved area beyond the edge of traffic lanes,
- median strips – freed of slopes and obstacles – having a width of at least 20 m except where protective barriers are used,
- added crawler lanes on steep uphill sections of roads,
- cuttings and embankments alongside the road not being steeper than 20%;
- proposed design principles for single lane rural roads comprising
- lane widths of 3.5 m and shoulders on each side of the traffic lanes of 1.3-1.5 m, providing a total carriageway width of approximately 10 m,
- cuttings and embankments alongside roads not being steeper than 20%, obstacle free zones extending for at least 3 metres on each side, a consistent horizontal alignment and proper road marking of curves,
- the usage of 'ghost' islands and hard shoulders in order to reduce the number of head-on collisions, and further measures, such as protective barriers and high friction surfaces, to prevent cars from unintentionally leaving the road, and
- proposed design principles for major urban junctions comprising
- clear, unobstructed view for an adequate distance to all road users regardless of weather conditions or day time,
- maximum speed differentials among road users of 30 km/h, and
- the arrangement of traffic streams in order to account for the best possible visibility and the prediction of the behaviour of road users.
Policy implications
A pilot programme for Road Safety Audits (RSA) on the design, construction and upgrade of Trans-European Roadway Network (TERN) roads is highly recommended, which should be launched by the European Commission aiming to establish a common RSA protocol.
Such a pilot should be assisted by comprehensive dissemination activities using proven EC communication channels. More widespread transfer and exchange of knowledge about the safety aspects of road design are a pre-requisite for achieving a sustainable road network across Europe.
In practical terms, harmonised road design standards and regulations for TERN building on best practice from advanced national schemes will be required to assure progress in the setup of a pan-European research database.