Tuesday, January 24, 2006

Size and growth do not (much) matter

My student Bumsoo Lee knows more about traffic in cities than anyone I know. I asked him to look at U.S. metro areas (pre-2003 definitions) with over 500,000 population in 2000. The largest was New York and the smallest was Fort Wayne. The ratio of their populations was 42.2:1; the ratio of their 2000 drive-alone commute times (based on census tract averages) was 1.3:1.

In the ten years leading up to 2000, the fastest growing was Las Vegas and the opposite (greatest decline) was Scranton, 83.3% vs. -2.1%. The ratio of their commute times was 1.1:1.

Do faster-growing and larger places have worse traffic? Not nearly as bad as the alarmists suggest. The alarmists tend also to be central planners who have no use for markets or road pricing.

Yet in the absence of pricing and without the levels of transit use that all right-thinking people prescribe, size and growth do not deliver doomsday traffic.

How will they get their plans right when their prognoses are wrong?