Report numberRA-2005-61
TitleDetermining location and type of security constructions on motorways on the basis of environmental characteristics
SubtitleInternational literature study
AuthorsFrank Van Geirt
Published byPolicy Research Centre for Traffic Safety 2002-2006
Number of pages59
Document languageDutch
Partner(s)LUC (nu UHasselt)
Work packageOther: Infrastructure and space

In this literature overview we investigate the different characteristics of safety barriers according to the European standard EN-1317 and other international sources. Next we make an overview of different types of roadsides and objects, which possibly need protection by a safety barrier.


Important recommendations for roadsides are:

  • A 10 m safety free zone on motorways
  • If obstacles are to be placed in the safety zone, they must be more forgiving by changing the design
  • If obstacles or danger zones are inevitable , a safety barrier must be installed

In the European standard, the safety barriers are described on a very abstract level. An subdivision is made by containment levels (strength), working width (maximum displacement) and impact severity levels (measure for the vehicle deceleration).


For motorways, the containment levels N2, H2 and H4b are recommended.


Standard, the H2 type is chosen.


The most important factor for choosing between H2 and H4b is the average annual daily traffic of heavy transport. Above 3000, the H4b level is recommended.


For bridges, the H4b level is chosen immediately due to protection of underlying roads, residential areas or industry zones.


In case of objects within the safety zone, without further danger zones, a N2 type is sufficient.


In this literature overview, we also look at the influence on safety barrier systems of several road and vehicle characteristics, like daily traffic, vehicle type, height of construction, material of construction, etc...


In a last chapter, we briefly describe 3 decision methods for safety barriers. These can be used during further investigations on safety barriers on Flemish motorways.

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The Policy Research Centre for Traffic Safety carries out policy relevant scientific research under the authority of the Flemish Government. The Centre is the result of a

cooperation between Hasselt University, KU Leuven and VITO, the Flemish Institute for Technological Research.


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