§ Mr. McCrindleTo ask the Secretary of State for Transport if his Department's preparations of traffic flow predictions on new carriageways include an estimate for extra traffic generated; and if he will make a statement.
§ Mr. Peter BottomleyYes, where appropriate.
The Department's appraisals of inter-urban road improvements do not normally include an allowance for any traffic generated by the improvement itself. They do allow for the reassignment, or diversion, of traffic from unimproved roads to the improved one, for traffic growth, and for the effect on traffic of known or expected local developments. Experience suggests that traffic generation from any one inter-urban improvement is likely to be small.
In urban areas where the demand for road space exceeds the supply for much of the time, or where travel conditions are especially difficult, as with crossing major estuaries, then road improvements can be expected to generate traffic, and current appraisal techniques can allow for such generation.
§ Mr. McCrindleTo ask the Secretary of State for Transport if he will estimate the average extra traffic generated by a new carriageway, if he has any plans for changing the method of preparing traffic flow predictions; and if he will make a statement.
§ Mr. Peter BottomleyWhere road improvements generate traffic, the extent of the generation differs significantly with the circumstances. No average can be given.
The Department monitors the effects of improvements on traffic, and is sponsoring research into the best way of modelling traffic in congested urban areas, with a view to improving its methods where that can be justified.