Monday, June 16, 2008

Drive 55 and Save Money

Slow down the next time you're driving on the highway.

A statistic that can save you money: fuel economy by speed.

15 mph - 24.4 mpg
20 mph - 27.9 mpg
25 mph - 30.5 mpg
30 mph - 31.7 mpg
35 mph - 31.2 mpg
40 mph - 31.0 mpg
45 mph - 31.6 mpg
50 mph - 32.4 mpg
55 mph - 32.4 mpg

60 mph - 31.4 mpg
65 mph - 29.2 mpg
70 mph - 26.8 mpg
75 mph - 24.8 mpg

(Adapted from Table 4.22, "Fuel Economy by Speed, 1973, 1984, and 1997 Studies (miles per gallon)", Transportation Energy Data Book: Edition 26-2007, U.S. Department of Energy, Energy Efficiency and Renewable Energy and Oak Ridge National Laboratory)

That means you save about $12 per hour on a freeway going 55 instead of 65, and only lose about 10 minutes. Compared to 75 mph, the savings are much higher. So if you don't have to get anywhere fast, drive 55 (or 50)! Use less gas and pollute less, compared with faster speeds.

2 comments:

Al said...

Your chart is a little bit misleading and simplistic. Many of the newer vehicles are geared to provide their best fuel mileage at higher speeds. It is simply a matter of the right gearing.

Unknown said...

YOU FORGOT THE LABOR COSTS OF DRIVING 55MPH. The added labor costs to business paying for employees being on the road 28% longer is far above the savings in gas. That added expense will ultimately result in increased prices of all goods and services.
For the sake of discussion, let's use the your math for the 100 mile trip: A car that gets 25 MPG would get 30.5 MPG at 55 MPH - Gas at $4.00 per gallon - Employee labor cost of $15 per hour.
Driving at 75MPH will take 80 minutes and cost a total of $36.00 in gas and labor costs
( use 4 gallons of gas at a cost of $16.00 and the labor cost would be $20 (1.3 hours x $15/hour))
Driving at 55MPH will take over 109 minutes and cost a total of $40.39 in gas and labor costs
( use 3.28 gallons of gas at a cost of $13.11 and the labor cost would be $27.27 (1.8 hours x $15/hour))
THAT’S AN 12% INCREASE IN COSTS BY SLOWING DOWN TO 55MPH. The burden labor rate for many service industries is actually $25 to $ 35 and more and therefore the problem is even worse.
The saving lives argument has also be very exaggerated. The chances of being involved in an accident on the highway increase the longer you are actually exposed to the risk. In other words, if you are on the highway an additional 30 minutes per day, your exposure to potential risk has been increase 30 more minutes. Being on the road longer also greatly increases driver fatigue. Driving while sleepy is as dangerous as driving drunk.
The claims that the National Highway death toll went down around 1974 due to the 55 MPH limit imposed after the 1973 Oil crisis has often been disputed. It has been suggested that this drop was actually due to new enforcement of seat belt laws and people driving less because of high gas prices.
As a business owner of a service industry, the interference by the Federal Government to make me inefficient will cost me thousands of dollars. Those who want to drive at 55 are more than welcome to drive 55. Just don't make everyone else along with the economy slow down with you!