I get your point, but what purpose would it serve? Taxing for carpoolig perhaps? The lower MPG/Passenger carried the more congestion tax you pay?

Of course, most vehicles rarely carry a full load of passengers.

MPG alone misses the point. I see all these marketing campaigns saying buy a smaller car with better MPG. But, doesn't that just put more cars on the road. I know it makes sense for one person commuting but shouldn't we be driving bigger vehicles with more people in them. SUV drivers have gotten a lot of criticism and I think it is sometimes unwarranted.

andyschieber, your point is clear, but I'm afraid Dwayne is right--what really counts is how many MPG you're getting for most of your miles. When I drive to work, I occassionally look around to access the vehicles. Something like 70 percent of them on my commute here in Kansas are heavier than 4000 lbs (truck, minivan, SUV) and something like 90 percent of the total vehicles participating in the morning commute are carrying one person.

The stay-at-home suburban moms that are delivering kids to school are driving fewer miles and with more seats full, but on the commute, the cars are empty. I even see the morning bus (Public Transportation), carrying something like six people.

Also, cars become more spacious every year, with fewer seats. In the 70's a station wagon held nine comfortably. Now a Ford Flex (huge) seats six. A bench-seat 1963 Falcon could seat six (we did). Few cars are available with a bench-seat cars today.

When you say 'calculate', do you mean on the window sticker? Because you can calculate the mileage any way you want--it's not on a displayed on the back window yet.

I personally believe people drive their SUV because they like it and because they can afford it, but also because most people can't own multiple cars and sometimes you Do need a big car. If you pull a boat on weekends, if you take coworkers out to lunch, you can't do that with a Civic.

If someone offered a cheap, one-seat motorcycle-car could people own both a big car and a little car then? I own multiple cars, but I still drive a bigger one when I expect to take the crew to lunch.

andy, i presume you drive an suv? how many passengers do you have on average? my 1 person car gets 45mpg

Three main problems in transportation. 1. Congestion (speed)2. Pollution (quality)3. Foreign oil demand (cost)

Two examples of solutions that don't address all three problems.

Give benefits to high mpg cars like HOV lane access, tax credits etc. This helps emmisions and foreign oil demand but neither of these improve congestion of traffic. In fact now in California everyone bought a Prius to drive in the HOV lane and now that is as slow too.

Give people access to public transportation. This works when congestion is really bad but the cost is really high to build the proper infrastructure with public money.

I am suggesting we calculate MPG X Passenger (MPGXP). If you have a small car like my Mini Cooper with 30 MPG and on average 1.5 passengers you MPGXP is 45. If have a SUV with 15 MPG and an average of 3 passengers your MPGXP is 45. Most new cars already have passenger sensing seats (for airbags) and MPG calculating computers. This combines those and records the number. Then periodically you go in to get you MPGXP certified so that you can qualify for your tax credit or HOV pass or whatever benefit can be offered to those with high MPGXP. This will work all three problems.

It is more than marketing, it involves public policy and city planning. The current public policies aren't working. Transportation remains Slow, Dirty and Expensive.

Andy, out here in fly-over country, we don't have (or need) HOV lanes, and the taxes on my 31-mpg 1993 Capri are like $40/year. So what's my incentive?

The actual cost of public transportation, once you've figured everything, is usually higher than private cars--they're very highly subsidized.

But you're going to create whole government agencies that police people's average daily miles/gallon--that can't be cost effective--figure the cost of ten bureaucrats and you've paid for any gas they might have saved.

If people get fed-up with congestion, they should move away from the coasts. Or get flying motorcycles (see my latest post).

As for reasons #2 and #3, I think electric cars are on the way, but Saudi Arabia just opened the two biggest oil fields in history and the head of Aramco told Lesley Stahl that he intends to kill electric cars and supply $55/barrel oil for the next 50 years. Maybe no change is coming?

http://www.theoildrum.com/node/4850

The bureaucracy will be minimal, it will work like fasttrack or MNpass. There is no policing more than now. It would be a tax credit, not affect your car purchase taxes. In the past you got a 4000 tax credit if you bought a hybrid to offset the higher cost. In this case you are getting incentives to drive more efficiently without infrastructure costs.

Believe it or not private cars are subsidized much more than public transportation. Who do you think pays for all the highways, cops and subsidizes automakers and oil companies. Taxpayers. Few cities actually have much public transportation. Many cities spend more on sports stadiums than public transportation.

Plus people can't just move away from their jobs. The coasts is where the jobs are and why they live with traffic. Unless, you give people tax credits to move into the boonies, it won't happen.

Additionally electric cars would only worsen traffic congestion.

http://www.ptua.org.au/myths/runcost.shtml