John Marriott's letter and the correspondence last week are well taken. The situation would be greatly improved with reform of driver behaviour, especially the tendency to travel nose to tail or tailgating as the North Americans call it.
Lorries are especially bad at this. There is hardly any serious attempt to correct driver behaviour in the UK, other than occasional attention to drink and drive, speeding, or after a serious accident has occurred.
Vehicles should travel at a minimum of three seconds headway, easy to count rather than estimate distance. That is 93m (almost a main road marker post apart at 70 mph). It would then be possible to filter in, between lanes or from a slip road following which, of course, everyone needs to readjust to correct the spacing again.
Traffic joining from a slower lane or slip road should filter in, at the same speed, behind a vehicle in the faster lane - not dart in front of one.
On most purpose dual carriageways, cyclist are at severe risk in many situations. Crossing a slip road, unless there is no other traffic at all, they are usually advised to dismount and cross it at right angles when it is safe to do so.
Bad and inconsiderate driving need to be recognised offences, punished by warning and then fines and driving bans, possibly followed by a retest. Thus a little of the current congestion would be relieved and driving would be regarded as a privilege rather than a right.
J E Gray (M), 29 Gallagher Road, Bedworth, Warwicks, CV12 8SB