Citation

Laker IB, Naylor AW. Transp. Res. Rec. 1993; 1419: 1-8.

Copyright

(Copyright © 1993, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

Early two-rope safety fence needed to be installed on a hardened running surface to avoid undulations in the terrain causing vehicles to contact the fence at varying heights, with the consequent risk of ropes slipping over the car hood or being run over. A new design uses four ropes at two heights with the lower pair of ropes interwoven between the posts. Standard U.K. tests with a 1500-kg car impact at 113 km/hr (70 mph) and 20 degrees showed that this design met U.K. Department of Transport regulations. Further tests with a 750-kg car, at the same speed and angle, demonstrated that rope heights are no longer critical: the fence can now be installed on nonhardened surfaces, thereby reducing the unit costs of installation. Where on-road space for installation of safety fences is restricted, post separations may be reduced from 2.4 m to 1.0 m; this reduces the maximum penetration, under standard impact conditions, from 1.7 to 1.2 m. Analysis of impact severity using the theoretical head impact velocity concept showed the four-rope fence to have impact severity characteristics that match the current U.K. design of semiflexible fence. Other advantages of the fence are that the ropes do not require replacement or retensioning after vehicle impact and that damaged posts are easily removed from ground sockets and replaced with new posts.

Record URL:
http://onlinepubs.trb.org/Onlinepubs/trr/1993/1419/1419-001.pdf

Language: en