In-car Satnav gives directions for greener route

In-car Satnav gives directions for greener route


5 January 2007 – An in-car satellite navigation system offers the fastest route to motorists, minimizing greenhouse gas emissions, although the best route might not be the fastest nor even the shortest. The system known as Satnav developed by scientists at the Lund Institute of Technology in Sweden has been programmed to work out the most efficient route, according to the latest issue of the New Scientist.

System developers Eva Ericsson and her colleagues have been testing the Satnav system and the tests on the streets of Lund have shown that their Satnav system can work out routes that are significantly less polluting than the standard options, according to the science magazine.

The researchers assigned fuel consumption factors for three types of car on 22 streets in a Satnav’s digital map database, which were based on the street’s class, taking account of information such as its width and speed limit and typical traffic flows in both peak and off-peak hours.

The test results showed that the average fuel saving on the 22 streets was 8.2 percent compared with journeys planned by other methods. None of the streets was particularly congested, however, and Ericsson estimates that savings on most journeys would be closer to 4 percent. A probe car was also driven around the same 22 streets sending real-time traffic flow data by radio to the Satnav system.

The researchers hoped that this would improve the choice of route still further, by showing where there were traffic jams, but it turned out that one probe car is not enough. At least 50 percent of jams need to be detected to make probe cars effective, but the lone car detected only 26 percent of them, they said.

According to a supplier of digital Satnav maps, commercializing such a system will be no easy task as making the measurements to give every street in the world a fuel consumption factor will be too expensive. However, this does not necessarily rule out their idea, the researchers said, adding if enough drivers can be recruited to volunteer their cars as probe vehicles, such detailed map information would be unnecessary.