Two recent studies from the Department for Transport point to similar concerns about traffic congestion. Responses from a Citizen’s Panel of over 500 participants indicated that the main concern of those who had experienced motorway congestion was that it makes journey times uncertain (62% of respondents; the same proportion were bothered because you can’t tell what the problem is or when it will be cleared). 

Responses from an Omnibus Survey of over 1000 participants indicated that 54% felt that uncertainty of journey times was the main reason why motorway congestion was a problem.

The main action taken by drivers to avoid motorway congestion was to set out at a different time than would be preferred (50% and 48% respectively).

As I argued in Chapter 8 of The Limits to Travel, the best way to tackle congestion is not by road pricing, but rather by providing motorists with good predictive information on future journey times, both to tackle the main problem of uncertainty about timing, and also so that they can make sensible decisions about whether and when to set out, and which route to take.  The fact that half of all drivers already vary their starting time is encouraging.  It shows that there exists a behavioural response which would be made more effective by better information.