The below Parliamentary question was asked by Stephen Metcalfe on 2016-03-16.
To ask the Secretary of State for Transport, what estimate he has made of the average length of a (a) delay and (b) tailback caused by the closure of the Dartford Crossing; and what effect a new crossing would have on those averages.
Andrew Jones
Typically there are in excess of 300 incidents per year resulting in partial or full closures of the Dartford Crossing. On average each incident takes approximately 27 minutes to deal with, often requiring a lane closure for safety. During this time queues build rapidly towards junctions 29 and 3 of the M25 and take a further 3 to 5 hours for the road condition to return to normal.
Highways England are continuing to explore ways of reducing incidents and improving clear up times. In the longer term, with a new crossing, there would be increased capacity to cross the river so the effect of any incident would be less extreme. If one of the tunnels were to close today, the northbound capacity of the crossing would reduce by 50%. With the new Lower Thames Crossing in place at either Dartford or Gravesend, a closure of one of the tunnels at the Dartford Crossing would still leave more capacity than exists today without an incident, so recovery times would be much improved.