Each year there are hundreds of incidents in which bridges are struck by vehicles too high to pass under them. Both rail and road users have been killed in these incidents. Look out for signs in this section and make sure that you are not a bridge basher.
All bridges with a clearance of less than 16 feet 6 inches (about 5 metres) are normally signed. Both regulatory roundels and warning triangles can be used, depending on the type of bridge.
Bridges particularly at risk from strikes may have a variable message sign that is activated by high vehicles passing through an infra-red beam. When the sign is activated, four amber lamps flash, the top pair alternating with the bottom pair.