Want to save the planet? Get a sat nav.

Social science research firm NuStats has just released the results of a survey that found drivers using sat navs use 12 per cent less fuel than GPS-less motorists.

The study evaluated three groups of drivers in Dusseldorf and Munich: those without a navigation system; drivers with a navigation system; and drivers with a navigation system that included traffic. None had used GPS devices previously.

The results revealed that the drivers using navigation devices drove shorter distances and spent less time driving. Overall fuel consumption dropped from 8.3 litres/100 kilometres to 7.3 litres.

Fuel savings offset sav nav cost

The study found anearly 2500 kilometre drop in distance driven per year per driver, and an average of 416 Euros (£370) in annual savings on fuel.

The findings also revealed a learning curve with the use of sat navs: greater decreases in trip times and distances were seen in the latter half of the study.

The largest reductions were seen drivers using sat navs with traffic built in during peak travel times (7-9a, and 4-7pm). Greater reductions were seen during non-routine trips.

The study results reflect more than 2,100 individual trips, more than 20,000 kilometers and almost 500 hours on the road. It was funded by digital mapping firm Navteq (owned by Nokia).

Update: It's a big old sat nav love-in, with Navman backing up Navteq's findings. Huw Bush, Head of UK Marketing Navman, says: "There's no doubt that using a sat nav device will help reduce fuel consumption. In addition, our S100, S200 and S300 sat nav devices now provide route planning options which help you avoid junctions and cut down on the number of times you stop and start your vehicle."