Slow down to save gas?

I found this article in the SF Chronicle which talked about saving gas by slowing down to 55mph on freeways. It’s an interesting read… gotta love the rude/emotional comments from both sides.

My take:

First of all, why are we looking at values for cars made starting 1988? I think it’s common knowledge that older cars are very gas inefficient. I’d like to see a more recent study on the cars out on the road today.

Second, the article assumes that driving slower is better, which is hardly conclusive. I think it really depends on the type of car you’re driving, how you drive, and what actual speed you’re driving at.

Ex: We all know that gas efficiency goes way down during stop and go traffic. It makes sense that if you accelerate and then decelerate immediately, you pretty much wasted the gas you just used to accelerate.

So if you drive with flow of traffic, you cause less people to have to decelerate and waste gas (especially if you’re not in the right lane). I guess for you it’s better, but for the greater good, traffic flow speeds is optimal.

On I-5 in particular, I’ve found that going at higher speeds with minimal breaking increases gas efficiency significantly (as in: it is possible to drive from Sac to LA without filling gas on the way).

For shorter distances, I think a good strategy is to drive at a constant speed and leave enough space in front of you so you won’t have to break much if the car in front of you slows down or stops.

This is regardless of speed, but it is probably easier to achieve this when you drive with traffic flow or slower. Keep in mind that slower speeds causes other people to have to break and get annoyed at you, increasing road rage and stress for everyone.

By the way, if you follow the range given in the article rigidly, you’d be speeding up on local roads to increase gas efficiency. That’s just as unsafe as driving on the freeway at 10-30 below speed of traffic.