This paper summarizes the results of the first UK trials of Chevron markings on the M1 motorway. The markings, which are inverted "V"s painted on the carriageway, are designed to assist drivers in choosing a safer follwing distance. They were laid at 40 metre intervals on two stretches of the M1 (one of 5 km and one of 4 km). Roadside signs advised drivers to follow with two chevrons between themselves and the vehicle ahead. Assessment of the effectiveness of the markings has been by two means: direct measurement of vehicle speeds and time spacings, and questionnaire interview surveys. The proportions of vehicles travelling at less then one second and at less that two seconds were recorded at three measurements points: upstream seconds were recorded at three measurements points: upstream from the markings (to provide control data), within the marked length, and downstream. The changes in these proportions were examined in each "after" measurement period (one week, one month, three months and six months) and tested for statistical significance. Vehicle speeds were also recorded and analysed, although the measure was not expected to have a particular influence on speeds. Questionnaire surveys were conducted at the first motorway service area downstream from each trial site. At the initial site (near Leicester) surveys were made at one week and six months after the markings were laid. At the Northants site, they were only made in the first week after. Members of the public were asked if they had noticed, understood, tried to use and had any difficulty in using the markings. Results indicate an initial large-scale reduction in accidents of both multi-vehicle and single-vehicle types, and the markings were generally found to improve close-following behaviour.
Abstract