Examination of the experimental length of 2 miles of anti-glare screen erected on the M.1 motorway, northwards from its intersection with the A.505 Luton-Dunstable road, shows that the protection given from headlamp glare is generally satisfactory. On flat sections of the road the height chosen for the screen is sufficient to protect commercial vehicle drivers in the slow and centre traffic lanes providing their eye-level when in the driving sea5 does not exceed 7 ft 6 in. Similarly the screen is low enough to prevent the drivers of small cars from seeing under neath kit. When the road is undulating some modification appears advisable. Approaching the crest of a hill on may see oncoming headlamps under the screen for a short time. To overcome this it recommended that for a distance of 500 ft on both sides of the best of a hill the fence should be carried to within a few inch of the ground. In a valley on the other hand, headlamps may be seen over the top of the screen. although the glare under such conditions is not usually serious, if it is thought desirable to eliminate it, the use of opaque transverse screens should be considered. As regards amenity, it is considered that the transparency of the fence directly to the side and rear of a vehicle leads to less monotony than a solid fence of the same size. Owing to the raising of the central reserve and the consequent reduction in the gap under the fence, it is thought that the fence may well encourage the formation of snow drifts on the leeward side. It has on the other hand the advantage of serving as a guide to the line of the road; moreover there are indications that it catches a considerable amount of spray and mud blown from one side of the road to the other and that it may assist in preventing runaway vehicles crossing into the opposite carriageway.
Abstract