§ Mr. Carmichael
asked the Secretary of State for Scotland if he will publish in the Official Report the capacity criteria used for road design, showing the upper and lower capacity figures for dual carriageway, trunk roads and dual two and three lane motorways.93W
§ Mr. McElhone
The upper and lower design flow figures, expressed in terms of 16 hour average daily flow for the month in which the heaviest traffic occurs, are as follows:
TYPE OF ROAD AND NUMBER OF VEHICLES PER 16-HOUR DAY Dual 2-lane all purpose with 7.3 metre wide carriageways 45,000–17,000 Dual 3-lane all purpose with 11 metre wide carriageways 60,000–35,000 Dual 2-lane motorway with 7.3 metre wide carriageways 56,000–35,000 Dual 3-lane motorway with 11 metre wide carriageways 85,000–45,000
Maximum figures could be reduced, possibly substantially, depending upon the flow characteristics of a particular road.