This chapter describes top-down and bottom-up approaches to driver information needs. The top-down analysis of driver information must distinguish between human beings as purely rational information-processing systems with many channels, and drivers as complex 'systems' with rational and irrational decisions, changing motives, attitudes and behaviour. Predictions of actual behaviour are unsafe, because behaviour is determined by many motives and attitudes are not strongly correlated with actual behaviour. Experts of the PRO-GEN group have evaluated some systems that inform drivers about impending danger or other vehicles, and reached the pessimistic conclusion that there is very little benefit from them. The three levels of car-driving behaviour are: navigation, manoeuvring and control. The bottom-up approach mostly uses questionnaires, simulations and prototypes; these methods have different costs, reliability and ecological validity. Questionnaires seem to be a cheap and effective way of finding driver information needs. Simulation can be a relatively inexpensive method of testing the likely effectiveness of safety measures. Prototypes for detecting and evaluating drivers' information needs should be used only when simulations are technically impossible. Some evaluation criteria for information needs are listed.
Abstract