§ Mr. Roger KingTo ask the Secretary of State for Transport if he will give for the M6 motorway between junctions 4 and 10A(a) the designed hourly capacity, (b) the daily traffic flow, (c) the peak time hourly traffic flow, (d) the hourly peak time through traffic, (e) the total traffic flow between the hours of 8 pm and 8 am and (f) the number of heavy goods vehicles per day, in each case: (i) at present and (ii) estimated for 1995 and 2005.
§ Mr. Peter Bottomley[holding answer Thursday 25 May 1989]: The Department uses design reference flows rather than traffic flow standards when designing motorways. These indicate only the starting point for detailed operational and economic assessment of options. The Department's design reference flows for a dual three-lane motorway—which describes the M6 between junctions 4 and 10A—range from 50,000 to 79,000 vehicles per annual average day in the design year (15 years after the year in which the road opens). However, the maximum capacity of any road in terms of throughput is considerably more than its "design flow" and will vary with the vehicle mix, road layout, time of day, time of year, and driving conditions.
The latest estimates of the annual average daily flow (AADF) for the M6 between junctions 4 and 10A relate to 1987. The figures are given in the following table.
Estimated annual average daily flow1 of all vehicles and of heavy goods vehicles on specified links of the M6: 1987 Junction All motor vehicles HGVs 4–5 71,000 14,200 5–6 77,200 13,810 6–7 98,300 18,580 7–8 115,000 24,850 8–9 111,500 21,930 9–10 110,300 21,540 10–10A n.a. n.a. 1 Both directions of travel. n.a. = not available.
Counts for peak flows and for flows between 8 pm and 8 am are available for only some of these links. The information is in the following table:
115WEstimates of through traffic were made for two links of this section of the M6 in 1984 and are given in the table.
Proportion of 12 hour daytime flow estimated as through traffic by type of vehicle and for specified junctions on the M6: 1984 Junction All vehicles Per cent. Heavy vehicles Per cent. 4A-5 35 45 10–10A 50 57 The Department prepares forecasts of national traffic. Where specific trunk road improvements are being assessed local traffic forecasts are prepared. Projections are not otherwise made for specific roads.