Thursday, December 18, 2008

A Transportation Question

Last week, I picked up my wife (who will join me working at USC--she will be a physician-faculty member at Keck Med School), our two cats and our wine in Bethesda and drove across the country. It was the first time we had done so in more than 20 years, and other than the fact that it discomfited one of the cats (a nervous nelly about life in general), it was quite a lot of fun.

As we travelled I-66 to I-81 to I-40 to I-30 to I-20 to I-10, I couldn't help but admire the remarkable achievement that is the Interstate Highway system. But I also couldn't help but wonder whether it was sometimes overdone.

In particular, the drive across West Texas was striking for its lack of traffic. The speed limit there was 80, and it is fun to drive unmolested at that speed. The scenery is hauntingly beautiful, too. But I wonder whether a 4-lane superhighway is really necessary there. Wouldn't a 2-lane highway with passing lanes on up-grades and limited at-grade intersections do the trick for such places? Or are the network benefits of having four lanes everywhere worth the cost? I don't know the answer to this--perhaps there is some literature? If we are going to spend a lot on infrastructure, we need to think carefully about such things.

2 comments:

Anonymous said...

Japan built a lot of roads that are sparsely used. It didn't result in robust economic growth. This is not a good investment, but rather the near equivalent of paying people to dig ditches, and fill them in again.

Anonymous said...

Remember, one of the stated purposes of the Interstate system was for military transport. A four-lane highway might make more sense in that case.

Also: Montana's I-90 was originally built in many parts of eastern Montana with full access control (meaning overpasses with on- and off-ramps), but only 2 lanes. I traveled on it in the early 1970's. It worked fine, since traffic was very light. Since that time (due to federal $$ availability??) it was upgraded to 4 lanes.