Raising the Speed Limit – a Logical Step or a Backward One?
Paul Le Masurier, MVA Consultancy, Claire Stephens, MVA Consultancy
The Paper will present outcomes of two pieces of research: one secondary and one primary. The results combine to give a qualitative and quantitative evaluation of the Government’s proposal to raise the national Motorway speed limit from 70 to 80 mph.
A key policy issue that has been concerning Government for some time is how to make better use of the existing infrastructure, given that the likelihood of increased funds for new infrastructure both now and in the foreseeable future seems somewhat low. As well as the difficult economic situation, there are strong environmental arguments against further road-building - people simply do not want more concreting over our green spaces.
A proposal that the Department for Transport (DfT) is considering is to increase the national speed limit on UK motorways from 70 mph to 80 mph. The implied increase in average vehicle speeds, and consequential journey time savings, should deliver substantial economic benefits. However, road safety statistics have demonstrated that with speed comes higher accident and fatality rates; which also have an economic (as well as social and emotional) cost.
So, what is the net economic outcome from such a policy; and are there other social consequences of raising the speed limit? Raising the speed limit may have other implications – would everyone simply drive 10 mph faster on out motorways, or would only those (the minority?) who currently drive at 70 mph or slower drive faster; and would the speed-limit on our motorways suddenly become more credible and/or more effectively policed, and would this in turn reduce accident rates?
Our Paper will attempt to answer these key questions. The authors have carried out an extensive review of substantial national studies undertaken in the UK to assess the economic impacts of raising the speed limit, and also the underlying assumptions – which have a huge bearing on the economic outcome. The authors have also developed a model capable of testing some of these key assumptions, and conducted social research (to be concluded this month) with speeding drivers that has gained insight into the motivations for their behaviours and how their behaviour may change in light of a change in speed limit.
The Paper will:
- provide an overview of the TRL and DfT studies that have both derived overall economic benefits of raising the motorway speed limit;
- provide details of the strategic model developed by the authors, and a demonstration of how the economic case varies according to changing assumptions, especially those on existing average speeds (by time of day) and assigned ‘cost’ of each road fatality;
- give insights into the attitudes and mind-sets of drivers who regularly conduct multiple non-compliant and illegal driving behaviours (and, in particular, speeding) carried out on behalf of Transport for Scotland.
The Paper will conclude with the authors’ views on the likely impacts of such a policy on economic benefits, road safety, and law credibility & enforcement.
Association for European Transport