Drivers and Road Signs

The function of the road sign system as an information channel for car drivers was investigated. The data were gathered from more than 5,000 car drivers stopped after passing a road sign on a Swedish highway. The main results are as follows.

1. The overall probability of a road sign being noticed on passing is not higher than about 0·5.

2. The different signs studied form a scale of recording probability of perception extending from a low group with a probability of being perceived of about 0·25 up to a group with probabilities between 0·60-0·75. The rank order of the signs is consistent between occasions.

3. The results verified the outcome of a previous investigation by Johansson and Rumar, 1966.

The main conclusion must be that the road sign system to a high degree does not achieve its purpose.