Referring to the problem discussed at http://redherring.com "The Future: A solution for bad traffic".

I imagine a kind of plugin into a car GPS navigation that is integrated with an online service. As you step into your car and enter your destination, the systems checks whether someone has registered (online) that he wants to go your way as well and how much he is willing to pay for it. "You might pick up John Smith at his house at this location and bring him to that location. He is will pay 3 euro for the trip. It requieres a detour of 600 meters. Please confirm now."

Or if you decided earlier where you go (because you are going there every weekday morning) your car might tell you: "John Smith is waiting for you at this location near you and wants to go to that location. You already confirmed. Do you want to call him because of changes or delay?"

John Smith entered his request at any given moment in the past. If it was days ago he is more likely to get a ride than if it was minutes ago. But it works either way. As he enjoys breakfeast he might check on his PDA, mobile or computer where his ride is located at this moment. He notices that your car is approaching his house and gets out.

The system cannot give any guarantee that you will get a ride. But the probability increases as
- many people with cars participate
- you increase the price you want to pay for the trip, there will be full time taxi drivers using the system for independent work
- you are flexible concerning the time of departure

There might be a user rating similar to ebay to know trustworthy and untrustworthy/not dependable people.

Problems:

• Cars with navigation systems are not widespread enough yet. Rich people who can afford a GPS might not be eager to carpool for a little money. But maybe we just have to wait a few more years.


• Navigation system producers would have to cooperate to make this integration possible. Maybe they are not willing to. It would be cool to have it OpenSource naturally.
  You would probably have to program the website and everything yourself and then offer a kind of plugin or standards to the navigation system producers.


• The comfort and value of this system increases with the growing number of participating people. A critical mass might be necessary to get it going. On the other side it might be sufficient to get every navigation system producer to join and activate the feature as a default setting.