This paper focuses on two factors regarding the display of visual warning information concerning low bridges to drivers of high-sided vehicles. The first is the design of the bridge warning sign. The second is the need to mark the low bridge itself in a manner that emphasises its height restriction. It was found that both the design of the sign and whether a border was added to it had significant effects on bridge warning sign comprehension levels. In general, signs with a coloured border performed better than those without a border. For the bridge markings it was found that, in the scenario studied here, the current marking standard performed worst compared to alternative designs, both on the accuracy of judgements of whether a bridge would be hit and on the level of caution associated with bridges that could be passed under safely. The implications of the results are considered.
Abstract