Evaluation of Impacts of Bilingual Signs on Road Safety in Scotland – with TRL

Bilingual signs were installed on selected trunk roads in Scotland following a feasibility study in 2002. Since the introduction of the signs, there has been no evaluation of what impact the signs may have had on driver behaviour, attitudes or accident rates. Transport Scotland commissioned TRL to lead a project investigating whether there is evidence that bilingual signs have had any effect on road safety and to establish the public’s attitudes towards the signs.The main report presents the results of the project, which used three sources of evidence to establish the likely effect of the signs on driver behaviour and attitudes in relation to road safety. Results of a review of international literature, analysis of accident data and a survey of 440 drivers are considered in the context of the Task Capability Interface model of driver behaviour.

The report suggests that while there is reasonable evidence to infer bilingual signs increase the demand of the driving task, drivers appear able to absorb this extra demand, or negate it by slowing down, which ultimately results in no detectable change in accident rates.