Sunday, January 25, 2009
A Letter to the EPA
Aggressive driving (speeding, rapid acceleration and braking) wastes gas. It can lower your gas mileage by 33 percent at highway speeds and by 5 percent around town. Sensible driving is also safer for you and others, so you may save more than gas money.
While technically correct, this statement is likely to be misinterpreted and lead to worse fuel economy. Rapid acceleration combined with rapid braking results in wasted gas. However, quick but smooth acceleration is more efficient than slow acceleration. Slow acceleration spends more time at less efficient vehicle speeds and at engine speeds that are less efficient while the engine is under the heavy load of acceleration. (However, accelerating too hard at low engine speed uses large amounts of gas when it is inefficient. This is why "quick, but smooth" should be emphasized.)
What is most important is that drivers remain safe and alert. Being aware of what is ahead leads not only to safer driving, but more efficient driving. Avoiding needless braking is where the fuel savings are. Being alert and getting up to speed quickly reduces the burden of congestion, but being over eager will result in waste. A driver should always be going the same speed or slower than the vehicle ahead, unless of course it is safe to go around. Accelerating too much results in unnecessary braking, and acceleration that is wasted and must be done over.
Stops are by far the biggest fuel waster. It should probably also be emphasized that encouraging communities to properly time traffic signals to reduce the amount of stops and set appropriate speed limits to keep traffic flowing smoothly will increase fuel economy better than any individual effort. When traffic lights and speed limits are set properly, driving at the posted speed will result in better fuel economy and time savings. Removing unnecessary traffic lights and stop signs should also be looked at.
Bad information has lead to declining fuel economy over past several years, despite rising fuel prices, the purchase of better fuel economy vehicles, and flat and declining amounts of driving. Adaption of moderately poor fuel economy driving behaviors resulting from bad information and price pressures are further compounded by their effect on congestion.
Dept. of Energy: The.Secretary@hq.doe.gov
EPA, Energy Efficiency and Renewable Energy Information Center: Web Submission Form
Sunday, January 11, 2009
Top Fuel Efficient Speed
Back in 1998, the average was 55mph for the most fuel efficient speed. But modern cars have improved a lot. The average has likely increased for passenger vehicles and truck, and the range for all vehicles has certainly increased. I've read claims that some cars get their best fuel economy in the 75 to 80mph range.
For starters, people confuse a gas tax with a Pigovian Tax. Pigovian taxes are largely accepted as economically stimulating in the long run. But a tax on a product or service that is associated with negative externalities is not necessarily Pigovian.
A Pigovian Tax is a tax that identifies negative externalities, prices their cost, and is spent directly on neutralizing the externalities (either by identifying the affected parties and compensating them, or spending on technology that prevents the externality). The national research council estimates the cost of externalities for gasoline consumption to be $0.26 per gallon for energy dependence and carbon emissions. That means that a Pigovian Tax would not be higher than $0.26 plus costs of infrastructure and pollution (Congestion cost cannot be included in a gas tax because congestion is a matter of when and where a vehicle drives. At most times and places, vehicles don't contribute to congestion.). The average tax on a gallon of gasoline is already $0.41 in the US.
Secondly, a gas tax is not a consumption tax. Gasoline is largely not an end use product, it is an input. Only for a small percentage of gasoline usage is gasoline an end use product (e.g., joy riding, snowmobiling, two-tracking, boating, recreational flying, luxury shopping and dining out, pyrophylic gratification). Usually it is an input for some other desired outcome.
Increasing input costs introduces risk to both individuals and businesses. When operating costs are higher, risk is higher and there is less certainty in the economy. It is harder to make good decisions.