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Roads to Nowhere

Our new study shows 80mph would only boost the treasury

Sian Berry's picture

3 October: Philip Hammond's 80mph 'stealth tax' would benefit the government's coffers, not drivers or the economy.

In his party conference speech today, Transport Secretary, Philip Hammond, said that an increase in the maximum speed limit to 80 mph would “deliver hundreds of millions of pounds of net economic benefits”.

However, new figures from Campaign for Better Transport – calculated by transport consultants MTRU – show that the government's economic claims about 80mph driving are very wide of the mark.

Our study looked at the balance of costs (extra fuel) and benefits (time saved) for drivers, and found that they will be left severely out of pocket if motorway speeds increase. This is very different to the effect on government income, with the treasury set to gain half a billion pounds in extra fuel duty and VAT payments every year.

The analysis found that drivers will pay out an extra £640 million a year for petrol and diesel while driving at higher speeds, and these extra fuel costs will far outweigh any economic benefits from reaching destinations slightly quicker.

A simple cost-benefit analysis of time savings vs fuel costs found that the overall cost to drivers will be the equivalent of around £200m a year. So Hammond’s ‘net benefits’ would only apply to the government’s own coffers!

It’s likely that any government cost-benefit analysis will produce different figures.  This is because models used by the Department fT to calculate fuel consumption at higher speeds are flawed.

These flaws come from the fact that the government’s standard ‘WebTAG’ model for fuel consumption is designed for a wide range of traffic modelling tasks, and does not work well at the high, steady speeds seen on the UK’s motorways. Instead, academics tends to prefer to use calculations based on fuel consumption at a steady speed as these better reflect motorway driving. These 'steady state' models result in much lower fuel efficiency being found at speeds above 70 mph.

Chart of different fuel consumption models Detailed cost-benefit figures have yet been released to back up the Transport Secretary’s claims, but the Guardian was told on Friday that carbon dioxide emissions from the policy would be 670,000 tonnes of CO2 per year, a figure that DfT officials called ‘modest’. This was challenged in the same article by Jillian Anable, from the University of Aberdeen who - like most experts - uses a steady state model to analyse motorway traffic. She calculated that the effect would be an additional 1.3 million tonnes of CO2 per year: double the increase claimed by the DfT.

Download and read our full analysis of the effect of 80mph motorways here.