- Crash barrier
A crash barrier is a barrier on a road designed to prevent vehicles from leaving the roadway to improve
road safety. Common sites for crash barriers are:
* median separators on multi-lane highways
* bridge supports
* mountain roads
The design of the road barrier is generally such that a vehicle hitting the barrier is steered back onto the road. This may be achieved by designing the supports so that they break off on impact, allowing the barrier to deform and push the vehicle back on track. In some cases cost cutting has led to a failure of this mechanism, with so-called "duck-nesting" (after the shallow nature of a duck nest) of barrier support bases. When this happens the supports tilt over at the base instead of breaking off, allowing the barrier to collapse and the vehicle to go over the barrier. Motorcycles are very vulnerable to crash barriers. Large vehicles with a high centre of gravity, such as
Sport utility vehicles, are also vulnerable to going over barriers on impact.
To prevent heavy vehicles going through or over the barrier and still maintain a low impact severity level, more stable systems like the German "Super-Rail" have been developed since the 1990s. It is tested to hold up and lead back trucks up to 40 tons while causing as low damage to smaller vehicles as the standard system of the 1930s.
With effect from January 2005 and based primarily on safety grounds, the UK’s Highways Agency's policy is that all new motorway schemes are to use high containment
concrete step barriers in the central reserve. All existing motorways will introduce concrete barriers into the central reserve as part of ongoing upgrades and through replacement as and when these systems have reached the end of their useful life. This change of policy applies only to barriers in the central reserve of high speed roads and not to verge side barriers. Other routes will continue to use steel barriers.
Concrete step barrier
Wikimedia Foundation. 2010.
Look at other dictionaries:
crash barrier — crash barriers N COUNT A crash barrier is a strong low fence built along the side of a road or between the two halves of a motorway in order to prevent accidents. [BRIT] (in AM, use guardrail) … English dictionary
crash barrier — crash .barrier n BrE a strong fence or wall built to keep cars apart or to keep them away from people, in order to prevent an accident … Dictionary of contemporary English
crash barrier — noun a strong protective barrier that is erected around a racetrack or in the middle of a dual lane highway in order to reduce the likelihood of severe accidents • Hypernyms: ↑barrier * * * crash barrier noun A protective barrier, usu of steel,… … Useful english dictionary
crash barrier — UK / US noun [countable] Word forms crash barrier : singular crash barrier plural crash barriers British a low metal fence at the side of a road or along the middle of a motorway … English dictionary
crash barrier — noun A barrier on the side of a road, to keep vehicles on the road … Wiktionary
crash barrier — guard rail, rail along a road which protects a car in an accident … English contemporary dictionary
crash barrier — noun Brit. a strong fence at the side of a road or in the middle of a dual carriageway or motorway … English new terms dictionary
crash barrier — noun (C) BrE a strong fence or wall built to keep cars apart or to keep them away from people, in order to prevent an accident … Longman dictionary of contemporary English
ˈcrash ˌbarrier — noun [C] British a low metal fence at the side of a road or along the middle of a motorway … Dictionary for writing and speaking English
crash barrier — /ˈkræʃ bæriə/ (say krash bareeuh) noun a strong protective fence erected by the sides of motor racing tracks and dangerous sections of roads; guardrail … Australian English dictionary