Road User Awareness and Understanding of the Meaning of Traffic Signs
P Harman, C Houldin, T Stuart, P Murphy, AECOM, UK
This paper will present details of primary research into the awareness and understanding of road signs and how improvements could provide improved safety.
As car ownership in the UK continues to grow, more pressure is being placed on the current highways infrastructure. The need to control and manage users of the network is therefore a key importance in ensuring acceptable safety levels and maximum usage capacity. Traffic signing is the main way of communicating with highway users and the vast amounts of information required such as access, parking and directions can lead to complex and cluttered messages which need to be conveyed in a very short space of time. The communication of these messages has lead to a number of compromises in both signage design and usage. As part of its traffic signs policy review, which was recently reported in the National Press, the Department for Transport (DfT) commissioned AECOM to undertake this study to explore road user awareness and understanding regarding the meaning of a number of traffic signs and subsequently identify any areas for improvement.
The primary research involved a two stage approach. Firstly a qualitative stage of in-depth interviews with members of the public and stakeholders to get initial feedback on the signs and provide information that would aid questionnaire design. This included cognitive interviewing to test the questionnaire for understanding. The second stage involved a quantitative household survey with over 800 members of the public.
Overall 36 signs were specified by DfT for inclusion in this research. A key aspect of the study was to design a computer aided presentation of the traffic signs for use in the survey. A wide range of signs were covered, including:
- Restricted and Pedestrian Zones;
- Cycling and pedestrian signs;
- Yellow box junctions;
- Bus lanes and height; and
- Weight restrictions.
The survey also tested whether adding a red bar to prohibitive signs (in a red circle) would affect the level of understanding. For example; a man in a red circle means "no pedestrians"; does adding a red bar across the man increase understanding. Signs were shown to respondents in the context of how they would usually be seen on the road network, in accordance with the Traffic Signs Regulations and General Directions (TSRGD). They were shown statically using a picture of the sign itself and a photograph depicting a scenario where that sign would usually be seen. A number of signs were also shown dynamically using a video simulation showing the sign as part of the driving experience.
Most previous studies which have sought to explore peoples? understanding of traffic signs have interpreted respondents? verbatim comments subjectively. This can be very difficult to do when signs have multiple meanings. We were very careful therefore to ask respondents a number of comprehension questions about what the sign was telling them and what action they would take as a result of seeing the sign. We could then determine if their actions would be legal or not or if they could result in a potentially dangerous situation. Following this we also told the respondent what the sign actually meant in order to get informed feedback on how easy the sign was to understand and how the sign could be improved.
For each sign, respondents were asked:
- their unprompted understanding of what the sign means; and
- a number of comprehension questions (usually3) that tested their knowledge of what the sign was telling them.
Respondents were then told by the interviewer what the sign actually meant, and asked:
- whether they found the sign easy to understand?; and
- whether the sign needed improvement and if so how?
The survey took place during January 2011 and was administered via CAPI (Computer Assisted Personal Interviewing) and over 800 interviews were obtained. A good cross section of users were included covering new drivers, experienced drivers, HGV drivers, foreign drivers, drivers who have difficulty understanding English, motorcyclists, cyclists and pedestrians.
The final report on the study was an integral part of traffic signs review that was published in October 2011.
The paper will present the findings of the study in terms of current understanding and potential issues in relation to non-compliance. An improvement in understanding of road signs could potentially improve road safety.
Association for European Transport