I bought a used 1996 Prius back in August 2005. It is the first generation hybrid which Toyota didn't intend for export. I bought it here in Christchurch from a fellow who imported it. He owned a Toyota parts importing business.
To help us keep some kind of internal discipline on costs, my family has maintained a system of "internal charges" to use the car. If any family member wants to use the car, he or she has to put $4 pocket money into the "Taxi" box. When the car needs petrol, we have the cash on hand. The $4 doesn't cover the full cost per ride, which by my calculations is about NZ$6.60, but the $4 does make us think about taking a bike instead.
Much of the cost of a ride is tied up in the capital cost of the car, which incentives greater use of the car, to lower the cost per ride. It's strange to take a bike, with this expensive car sitting in the drive.
The solution is to spread the use of the vehicle over more people. The NY Times has a lovely article which explains that some new businesses are putting shared cars in neighbourhoods, and charging per use. People who use these systems drive much less, use public transportation more, and save a lot of money. It is something I've always wished we had. Time-shared vehicles will work in big cities, where most people live.
What are the implications for society? First, we're going to need far fewer cars - Zipcar has 50 members per car. That means the car industry is going to shrink. Second, we'll need fewer parking spaces. That means that city living will become denser, as garages are turned into living space. Cities will also have more green space, as some parking lots are turned to parks. Third, cars will be nicer, because the capital cost is spread over more people.
As a fourth impact, since we will have fewer cars on the road, we won't need such big roads. That would be great, but as these effects occur only at the margin, it will take decades for such changes to occur. Too bad! At least we're going in the right direction.
There is an interesting implication for operations research. The NYT article points out that people who use shared vehicles plan their travel much more carefully. That suggests that people will want GPS units with better routing algorithms.