§ Mr. Warrenasked the Secretary of State for Transport what traffic flows currently qualify trunk roads for consideration as dual carriageways; what were the qualifying traffic flows 10 years ago and 20 513W years ago, respectively; and what were the dates of any changes in the qualifying flows.
§ Mr. HoramThe level of traffic flow that qualifies a trunk road for consideration as a dual carriageway depends upon a number of factors, including the extent and duration of peak flow conditions. By current standards the lowest level at which consideration would be given to dual carriageway provision is the expectation that the average daily flow in the peak month will exceed 17,000 vehicles during a period that is normally 15 years from the date of construction.
The corresponding flows 10 and 20 years ago were 8,500 and 6,000 vehicles per day, these standards having been established in 1961 and 1950, respectively. The current standards were adopted in 1974.