Abstract
86 children between the ages of 5 years 5 months and 8 years 4 months were given a simple road crossing test on a small road system. Following a lessen on the Green Gross Code a subsequent crossing test was made and a questionnaire on the children's knowledge of the Green Gross Code was administered. The results show: (1) the importance of age in the development of road crossing behaviour, and (2) for children aged 5½-7 years the lack of effectiveness of one lesson on the Green Gross Code. Correlations were found between age and questionnaire scores.