Putting an Actual Dollar Value on Gas Saved from Driving Slower

I've been suspicious about all the exhortations to save gas by driving slower. Of course, it is true -– to some degree. But just how much? And what's that savings worth per hour?

So I wandered the Internet. Most of what I found consisted of vapid "go green" mantras with undocumented percentages thrown around -– often up to 30% savings from driving slower.

Finally I found a good study by Consumers Reports running a more controlled experiment. What CU claims (remembering their hard-left bias) is that a Toyota Camry or a Mercury Mountaineer SUV going from 75 to 65 MPH would save a bit over 14% in gas consumption. Let's assume this study is accurate.

Particularly interesting is that CU tells us that going even slower from 65 to 55 MPH apparently saves very little more -– the fact that they didn't give the actual figure tells me the reduction is truly minimal. Most of the usage difference seems to be related to wind resistance.

Well, I drive compacts such as a Camry. Assuming gas is $4.50 a gallon, if I drive 65 MPH instead of 75 MPH, the saved time translates to a cost $9.87 saved per extra hour behind the wheel. Better than minimum wage, but less than what many people value their time. If you have more than one person in the car, you effectively split that cost, making the case for driving faster more telling. Of course, the more gas costs, the more you save per hour driving slower.

There are other factors to consider. Maybe you enjoy zoning out while driving -– taking in the view, listening to music or books, or having riveting conversations with yourself. Those are all painless ways to save money while driving slower.

There's another aspect I'd like to see better researched. It appears that wind resistance rises exponentially the faster you go. Apparently the wind resistance from 55 to 65 is only marginally stronger, so the gas savings are inconsequential. Hence I suspect that driving 70 instead of 75 (splitting the difference with 65) would save 70% of what driving at 65 would save. 70 MPH is a good speed, and no one will flip you off as they roar past.

Two other gas consumption nuggets that seem to be verified by studies:

A. Driving on the highway with your A/C blasting has little effect on gas mileage.

B. Surprisingly, for most drivers, the cruise control is a very significant gas saver -– as much savings as driving slower, for many people.

Now you know.

http://finance.yahoo.com/family-home/article/104752/Slow-Down-a-Lttle-Sa...