Why Rep. Speier's proposal to cut the speed limit is a bad idea

Accordig to the Mercury News, Rep. Jackie Spier is proposing to impose a national 60MPH speed limit. Here's why it's a bad idea and why there are better alternatives:

Let's do some calculations based on some of the news reports we've heard about Rep. Speier's reducing the national speed limit to 60.

Say a typical commute is 30 miles, gas is $4.50 a gallon, and a typical car gets 20MPG at 80MPH. Using Rep. Speier's numbers, slowing down to 60 would increase the mileage on that car to 25MPG.

MPG	Gallons	$ Cost	$ Savings	Speed	Time Taken	Time Savings
20MPG	1.5	$6.75	0	80MPH	22.5 min	7.5 min
25MPG	1.2	$5.40	$1.35	60MPH	30 min	0

As you can see, driving at 80MPH, it costs $1.35 to save 7.5 minutes. This works out to being paid $10.80 an hour to slow down.

So, it's really only worth it to slow down for those folks making less than about $21,600 per year.

Calculations of this sort were the reason that I supported the move to eliminate the 55MPH national speed limit back when the republicans took over congress in the 90s.

Personally, I'm saving both gas and time having recently moved so that my wife and I are both closer to our jobs, friends, etc. It would be great to see Congress encouraging people to make that sort of change as part of the solution. I really believe that this is the way we're going to have to solve this long-term (i.e. over the next hundred years): we need to adopt a more european model of significantly higher population density, shifted closer to cities that are walkable and bikeable.