Green: traffic speed and climate change

When a motor vehicle (car, van, lorry) is travelling steadily at its optimum speed for minimising fuel consumption (usually between 25 mph and 50 mph), its fuel consumption is very much lower than when it is travelling fast or changing speed. I now know this for sure because my replacement car has a fuel consumption computer. I am able to see in numerical terms, the effect on my car's fuel consumption of driving style choices that I make.

During the mid-1970s, in response to massive increases in the price of crude oil imposed by the OPEC countries (and therefore causing a significant shift in the balance of trade), the UK national speed limit was reduced in order to reduce national fuel consumption. From Wikipedia: "It was reduced to 50 mph (80 km/h) in response to the 1973 oil crisis, and restored to 70 mph (112 km/h) in 1974."

In relation to the US, I found the following paragraph here:

"In the midst of an energy crisis touched off by conflict in the Middle East (see October 17, 1973), President Richard Nixon signs the Emergency Highway Energy Conservation Act, establishing a maximum national speed limit. No highway projects may be approved in any State having a maximum speed limit over 55 m.p.h. The Act, part of a nationwide effort to save oil, is a result of an oil embargo imposed by the Organization of Petroleum Exporting Countries that forced Americans into long lines at gas stations. President Nixon estimates the new speed limit can save nearly 200,000 barrels of fuel a day."

Were the UK national speed limit to be reduced again to 50 mph, the consequence would be a significant reduction in greenhouse gases produced by motor vehicles. Additionally, motorists would save money because they would need to buy less fuel. Lower road speeds would permit roads to carry denser traffic, thus, perhaps counter-intuitively, reducing some congestion. Further, according to the police, excessive speed is indicated in a majority of road traffic accidents. Limiting speed to 50 mph has the chance, therefore, of reducing the number of accidents, their severity and the number of casualties. (I read somewhere that reduction in the number of casualties of road traffic accidents had plateaued, and that further measures were going to be required if the numbers were to be reduced further.) Longer journey times for lengthy journeys might mean that more journeys would be undertaken using public transport, and there might be a long-overdue increase in the use of video-conferencing, and thus a reduction in the number of journeys undertaken.

To my knowledge, no-one is talking about this proposal as an option to reduce greenhouse gas emissions from transport. Is there a reason for this? Am I missing something? As a first step, it would seem like an obvious and relatively cheap and pain-free adjustment that could be made.

Some further thoughts:

1. The speedometer in most UK cars runs up to 160 mph. This is bizarre because the national speed limit in the UK is 70 mph, and (with the exception of Lower Saxony) nowhere else in Europe exceeds 130 kph. The unnecessary range of the speedometer dial achieves two things: I am less clear about my precise speed because the reading is always limited to a small proportion of the speedometer dial; I am always given the sense that I am driving slowly compared with the apparent potential of the car.

2. My car has the potential to travel much faster than I shall ever be legally allowed to drive it.

3. Every morning when I commute to work, an overwhelming majority of the traffic noticeably exceeds the speed limit for substantial portions of the journey.

4. Despite huge negative attention devoted by UK motorists and news media to speed cameras on UK roads, the reality is that the number of speed cameras relative to the extent of roads on which speeding takes place is pitiful.

5. Few UK cars are fitted with cruise control. The price for retrofitting cruise control is prohibitively high. Cruise control could help motorists to observe speed limits.

6. The overwhelming majority of car advertisements in the UK emphasise using cars for fun and excitement. This is not a message that is compatible with attempting to reduce CO2 emissions and traffic. Resolving issues related to climate change requires that people stop seeing their car as a form of recreation.

7. The points I have made above impact on the daily lives of ordinary people. I suspect that many people are willing to make token efforts to mitigate climate change, provided that they are not required to change how they live their life. I believe that climate change is orders of magnitude bigger than the majority of people are appreciating. Token efforts sound to me like rearranging deckchairs on the Titanic. Until people realise that real change needs to take place, across a range of lifestyle issues, such as the speed at which they drive their cars, CO2 emissions are not going to fall.

Beatrice 16 May, 2008 15:11 commented...

Yes, you're absolutely right about deckcahairs on the Titanic. I think people just cannot cope with the enormity of the implications of runaway climate change and so refuse to accept it is real. There are some interesting articles about on the psychology of climate change denial eg this one by George Marshall:http://www.ecoglobe.ch/motivation/e/clim2922.htm

Postscript
Whilst what I have written above sounds a little like pious polemic, I believe it sufficiently both to have reduced my driving speed to 50 mph where the speed limit is 70 mph, and to have changed my driving style so that I accelerate only slowly and, within the limits of safety, brake as little as possible. It has taken a while to drive more sedately, detaching myself from the frantic impatience of other motorists. I sometimes resort to singing "I feel pretty" - it helps.