Gary Haq: Life in the slow lane... how drivers can put a brake on the world’s petrol crisis

The Spanish government has reduced the speed limit on main roads from 75mph (120 km/h) to 68mph (110 km/h) in an attempt to reduce fuel use. This has been in response to the unrest in Libya and concern that it will spread elsewhere in the Arab world. Spain is dependent on imported oil, with about 13 per cent coming from Libya.

The reduction in the speed limit is part of a wider package of measures to reduce energy use. As people spend more money on foreign fuel, they have less to spend on buying products made in Spain which could slow the recovery of the Spanish economy.

However, critics see lowering the speed limit as a desperate measure and are sceptical it will achieve the savings the Spanish government claims.

US President Richard Nixon took similar action in 1973 in response to the oil crisis then. He introduced a speed limit of 55mph (90 km/h) in 1974 in a bid to reduce fuel consumption by 2.2 per cent.

The measure only achieved a fuel saving of about 0.5 per cent but had the additional benefit of reducing road deaths. In contrast, France tested the strict enforcement of speed limits on main motorways in 2004 and achieved a 19 per cent reduction in carbon dioxide emissions.

In the UK, petrol now costs on average about £6 a gallon. However, rather than reducing the speed limit, the Conservative-led coalition has actually talked about increasing it. Recently, Transport Secretary Philip Hammond was reported to have suggested increasing motorway speeds to 80mph in an attempt to shorten journey times and help the economy.

This is despite the Parliamentary Advisory Council on Transport Safety claiming that raising the speed limit to 80mph would increase motorway casualties by between five and 10 per cent.

Lowering the speed limit will be a challenge, as many petrolheads will perceive it as an infringement of their human rights and another attack in the “war on the motorist”. According to a 2008 Department for Transport study on speed, drivers can be divided into three groups: speed limit compliant, moderate or excessive speeders. Excessive speeders tend to be young, male, risky drivers who are often involved in accidents.

The study also found that a substantial number of drivers report that they regularly break speed limits of 30, 60 and 70 mph.

At speeds of 50mph and above, drivers tend to over-estimate the time gained by going faster and the time lost by going slower. In order to encourage people to drive at lower speeds, this “speed-time fallacy” will need to be addressed.

Reducing speed is seen as a quick hit as it relatively easy to implement. It requires little legislative and capital investment and can achieve rapid savings in fuel consumption as well as cutting carbon dioxide emissions.

A lower speed limit will, of course, increase travel time, which will further depend on road conditions, weather, traffic congestion and roadworks. Despite this, limiting the speed at which we drive offers a number of social and environmental benefits.

The exact fuel and carbon dioxide savings of reducing the speed limit are influenced by vehicle weight, engine and fuel type, driving style and traffic flow conditions. Increasingly, optional extras such as air conditioning have increased the average fuel use of a car.

According to the UK Energy Research Centre, introducing and enforcing a 60mph speed limit could reduce carbon dioxide emission on average by about two million tonnes each year.

In addition, becoming a “smarter driver” and being conscious of how to drive efficiently has the additional benefits of reducing annual fuel bills, wear and tear on the vehicle and can result in safer and less stressful journeys.

By 2030, global oil production is expected to decline as demand increases. The exact timing of the tipping point when oil availability begins to decline, and the ensuing rate of that decline is debateable.

However, there is increasing recognition that the “peak oil” phenomenon is real. National and local governments have all already begun designing policies to cope with the lack of cheap oil – with Sweden committing to be oil free by 2020.

Reducing the speed limit will be the least of our problems as we will be forced to make more fundamental changes to our energy intensive lifestyles in order to adapt to a world of increasing energy insecurity.

Dr Gary Haq is a senior research associate and human ecologist at the Stockholm Environment Institute at the University of York.