Both fixed-site and moving-base observation techniques can be used to study driver behaviour over a section of roadway. The effects of pavement marking and presence of other vehicles on the lateral positions of cars are reported for data collected by both techniques along suburban roads. Unobtrusive cameras were used for data collection to allow observations to be made on drivers who were unaware that they were being observed. The major dependent variable measured was lateral displacement of the car from the road centreline. The results of two studies indicated that there were reliable differences in the pattern of lane-keeping and lateral position between road sections that were similar in all respects except for the pavement delineation marking used. These data were also influenced by the presence of other vehicles. When drivers approach from opposite directions while in adjacent lanes, there is a systematic linear movement away from the road centreline which commences when the cars are separated in time by between 2.5 and 4 seconds, and increases as the gap between the vehicles decreases. The time at which movement commences appears to depend on the delineation marking used. Use of direction indicators by drivers was shown to depend on whether lanes were defined by pavement marking.
Abstract