§ Mr. Portilloasked the Secretary of State for Transport whether three-lane single carriageway road sections display worse accident statistics than two-lane single-carriageway and duel carriageway sections; and if he will make a statement.
§ Mrs. ChalkerPersonal injury accident rates on roads with rural characteristics, having speed limits over 40 mph and excluding accidents at junctions, depend on a number of factors in addition to road markings (and road width). However, on average, the rates for good three-lane single carriageways are about the same as those for good two-lane carriageways of the same overall width and characteristics; typical rates for these types of carriageways are about 0.20 accidents per million vehicle kilometres compared with 0.11 for new purpose-built dual carriageways. But, the sample of three-lane carriageways on which this statement is based is necessarily small because since the early 1960s the Department has not marked single carriageways in three lanes except in two cases. The first includes lengths of road having good alignment and exhibiting good long-term accident rates. The second case is that of "climbing lanes" where the two uphill lanes are given priority and the marking system involves the use of double white lines to maintain safety.
There is relatively little three-lane single carriageway trunk road with urban characteristics having speed limits of 40 mph or less.