Some of the variables that affect traffic volume are zoning laws, construction of new shopping malls, and the availability of public transportation.

NPR: Bumper to Bumper: Predicting Traffic Flow

That is, given the availability of public transportation in New York, how much will the extra revenue per vehicle be offset by a decline in customers?

FORBES: Yankee Stadium's Parking Woes

Their idea is compelling: Reduce dramatically the use of oil in America's transportation sector by utilizing existing technologies massively and rapidly to ramp up the availability of alternative fuels (ethanol, methanol and electricity) and the vehicles that can use them.

CENTERFORSECURITYPOLICY: The winning alternative

The least painful and most sensible would be to expand dramatically the availability and use of alcohol-based fuels and electricity as means of powering the transportation sector, where most of our oil is currently consumed.

CENTERFORSECURITYPOLICY: War footing or GODSAVEUS

If it is true that we may expect a decline in the availability of cheap crude oil, and hence diesel and petrol fuels, upon which essentially all world transportation, manufacture and the production and transportation of food, and thus global growth depend, the news on the CO2 emission front must be good.

FORBES: Global Warming Is No Threat?