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The Highways Department had completed bridge parapet and roadside barrier enhancement works at 39 priority locations as identified by the Tuen Mun Road Traffic Incident Independent Expert Panel, the Assistant Director (Development) of Highways, Mr Ng Kam-chi said today (January 27).
The department had also conducted full-scale impact tests and computer simulation analyses on the enhanced designs of bridge parapets and roadside barriers for the containment of double-decked buses.
ˇ°The enhancement works include strengthening of existing three-rail metal parapets by addition of intermediate posts and top rail, strengthening existing concrete parapet by addition of two strong rails and posts, and replacing the existing parapets with four-rail parapets and providing a row of three-beam barriers in front of parapet where space available. The enhancement works also include upgrading of the existing roadside barriers to double three-beam barriers,ˇ± Mr Ng said.
New designs of bridge parapets and roadside barriers had been developed and used to enhance road safety, in particular, to enhance the containment capacity of the parapets for heavy vehicles and double-decked buses.
ˇ°Parapets and barriers, however, cannot prevent traffic accidents. They mainly provide a passive line of defence to reduce the severity of accidents. Driver behaviour is the most important factor in enhancing road safety,ˇ± Mr Ng stressed.
The department commissioned engineering consultants to validate the new designs by conducting full-scale impact tests and computer simulations. Four full-scale impact tests were carried out on the new parapet and barrier designs last year. Three double-decker buses and one saloon car were shipped to a testing ground in Beijing for the tests.
ˇ°The full-scale impact tests provide useful data for the development of sophisticated computer models to simulate various impact situations.
ˇ°A real bus was dismantled and data collected to establish a realistic bus computer model. The computer models were calibrated against the impact tests and were found to be capable of simulating real impact situations. Using the calibrated computer models, more simulations were done to investigate the impact of buses and other vehicles on different designs of parapets and barriers at different impact angles, speeds and vehicle loading conditions.ˇ±
ˇ°The studies confirm the adequacy of the new designs,ˇ± Mr Ng said.
Ends/Friday, January 27, 2006
Issued at HKT 17:39
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