This paper was presented at session 36 - signing, delineation and guidance 1. A general methodology for investigating the visual information needs of motorists is developed. Road lighting is itself not an information source but, rather, reveals information of an informal nature. For freeway driving, position keeping is an important aspect of the driving task and change in angular size of the rear of the followed vehicle is the important visual information. Data are presented from three investigations, using laboratory simulation, linking light level to time for detection of change of visual angle (change in headway), to initial angle (headway) of the followed vehicle and to its subsequent acceleration or deceleration. The data yield a general relationship between the parameters, show the effect of vehicle presence lights on the relationship and permit a comparison with data from car following studies. The application of findings to freeway lighting specification is discussed. The number of the covering abstract of the conference is IRRD No. 239340.
Abstract