This paper reports on an experiment conducted to estimate the effects that reading different quantities of text information has on driver attention and driving quality. 39 subjects each drove three motorway journeys in the TRL driving simulator, guided by direction signs of different complexities, presented either on the roadside, in the car, or in both locations simultaneously. Reading from the in-car screen was found to cause significantly more steering deviation than reading the roadside signs, with older drivers, particularly those with poor near vision, suffering the greatest distraction and degradation in driving quality. Comparison with previous work showed in-car presentation improved reaction times for simple signs but degraded driving performance for more detailed signs. These findings suggest minimum text sizes and maximum complexities for in-car information should be avoided.
Abstract