The behaviour of car drivers has been analysed in relation to the width of sealed shoulders. The lateral positions and speeds of both free moving cars and cars with meeting traffic were analysed quantitatively from video in a before- (shoulder width 1.20 m) and after situation (shoulder with 0.30 m). In the after situation the free moving cars show a shift of 0.10 m to the middle of the road. In both the before- and the after situation there is a shift of 0.17 m to the right in case of meeting traffic compared with the situation of free moving cars. In motorists' strategy of lateral positioning, the middle of the traffic lane seems important. In most cases the driver's strategy is to keep his own position slightly left from the lane centre. This position shifts to the lane centre in case of a wide shoulder and with opposing traffic. There are no differences in driving speeds between the before- and the after situation, except a small decrease of speed in the after situation with meeting traffic. The results are quite well in line with the results from the literature.
Abstract