Trrl Lr 634
Experimental markings have been used in the roundabout at Slough - Central motorway interchange, to ease the problem of evening peak hour queues in the westbound exit slip road from M4. An exclusive lane was marked in the existing roundabout carriageway to allow left-turning traffic from the slip road to filter through roundabout, without having to give way to circulating traffic. This movement accounted for two-thirds of the slip road flow. With similar before and after levels of circulating traffic, a 36 percent increase in slip road capacity was recorded and a corresponding increase in total flow through the 'weaving section' of 12 percent. Queues of left turning vehicles, which had previously blocked back onto the motorway main carriageaway, have largely disappeared. No personal injury accidents were reported in the first seven months of operation