Transportation vehicles such as ships and cars are most fuel efficient when driven within a specific range of speeds. Significant fuel efficiency gains can be made if the speeds of these vehicles are restricted to those around which their efficiency is greatest. The energy efficiency gains found through speed-restriction measures are considered ‘low hanging fruit’ because these measures do not require additional technological development to be implemented. If policy changes in the transportation sector requiring speed reduction were adopted, they could very quickly prompt a significant reduction in fuel usage.
In an effort to reduce the fuel consumption of its vessels, Maersk, the world’s largest container shipping company, has implemented a policy reducing the maximum cruising speed of its fleet by 50%. This means that its ships cruise at 12 knots, instead of the typical 24 knots, in order to maximize engine efficiency. This speed-reduction policy was originally implemented in response to the high oil prices during 2008 in order to save money on fuel. According to a recent article in the New York Times, lower speeds have accounted for a 30% increase in the fuel economy of Maersk ships.
In addition to saving money on fuel, the speed-reducing policy also has environmental benefits. By reducing the amount of fuel burned, the amount of air pollutants, such as C released to the atmosphere also is reduced.
Despite the money saved on fuel and the environmental advantages of this speed-reducing policy, some argue that this is a bad business move which will alienate customers whose lead-times will increase due to the longer transportation times and who will consequently be forced to increase their inventories. In a fast-paced global economy, where goods need to move quickly from Asia to Europe and North America by ship, it is unlikely that Maersk’s customers would be willing to stomach an increase in lead times without seeing some of the economic benefit of reduced fuel costs. In order to address this need, the New York Times states that Maersk is considering introducing variable rates, depending on the speed of delivery.
The ability of policies, such as the one implemented at Maersk to reduce fuel consumption and air emissions, has prompted some to suggest that similar measures should be taken to reduce fuel consumption in automobiles by reducing speed limits on the highways. According to a US DOE site providing tips on how to drive more efficiently, most vehicles reach their optimal fuel economy at speeds below 60 mph. After 60 mph, each extra 5 mph that is driven utilizes more gas, costing an equivalent gasoline price increase of approximately $0.24 per gallon. The DOE estimates that by observing the speed limit, vehicles could see an increase of 7-23% of their fuel economy, depending on the type of vehicle driven.
However, despite the economic and environmental benefits of lowering the maximum speeds of automobiles, it is unlikely that such a policy would be effective, at least from a historical perspective. From 1974-1987 a National Maximum Speed Law was in place which prohibited speed limits above 55 mph. However, this law was widely ignored due to conflicting views on the state level and failed to significantly reduce fuel consumption.
Nonetheless, programs which educate drivers about the economic and environmental benefits of driving at a reduced speed to maximize engine efficiency might successfully and significantly reduce the amount of fuel consumed in transportation. Additionally, efforts to expand the policies begun by Maersk in other areas of the transportation energy sector should be encouraged.