Older drivers fail in intersections: speed discrepancies between older and younger male drivers.

A high percentage of older drivers' accidents occur in intersections when entering the traffic or crossing a main road. The problems may be in perception or attention, motor performance or inadequate interaction with other road users. Attempts to explain older drivers' problems have mostly focused on the properties and behaviour of the older drivers only, without considering the interaction between older and younger road users. The descriptions of older drivers' problems in intersections are usually based on accident data. This study aimed to describe the normal behaviour of older drivers, including driving habits, attention patterns and interaction with younger drivers. The driving behaviour of young, old and middle-aged male drivers was studied using video cameras and observers in three T-shaped intersections in Sendai, Japan. The results showed no differences in attention behaviour between the age groups as measured with head movements. The age groups had different acceleration habits and thus different turning time, which also varied depending on whether the vehicle on the main road came from the left or the right. Also the outcome of the turning manoeuvre was dependent on age. The time margins to the vehicles on the main road were shortest when an old driver was turning and a young driver approached on the main road. The time margin between the turning driver and the vehicle approaching on the main road was clearly shorter when the latter vehicle was a motorcycle than if it was a car. The results are discussed in relation to the literature on the risk behaviour of old drivers.