Samenvatting
Procedures and results of two experimental studies dealing with the differential effects of design features of message content are described. The first of the two studies reported here attempts to compare the effects of an individual message that explicitly shows the possible consequences of driving after drinking with another largely identical message, in which these consequences remain implicit. The purpose of the second study was to assess the differential effects of two motivating appeals in road-side posters recommending the use of headlights during daytime driving.