From Mark Robinson
You are right to point out that radar systems to protect railway level crossings will “need some development” (13 November, p 3). Qinetiq and (more worryingly) Network Rail seem to have misunderstood how automatic half barrier (AHB) crossings work.
AHB crossing barriers are triggered when an approaching train is around 30 seconds from the crossing – by which time the train may have difficulty stopping. This is a deliberate design feature, to minimise the time that the road is closed to traffic. For radar obstacle detection to be effective, the barriers would need to close far earlier. This would lead to more accidents because drivers would be tempted to zigzag around the barriers if forced to wait a long time for the train to arrive.
All is not lost, however. One proven technology that could reduce deaths on AHB crossings is a high central reservation on the approach, to discourage drivers from weaving around the barriers. Another is to install cameras recording car registration plates, combined with stiff penalties for transgressors.
Glossop, Derbyshire, UK
