Photo: Flickr, CC
"drivers using navigation devices drove shorter distances and spent less time driving"
Before getting started, I must point out that this study was funded by Navteq (owned by Nokia), a digital mapping firm. The methodology and conclusions might still be spotless, but full disclosure is always best. Now back to the study: It "evaluated drivers without a navigation system, drivers with a navigation system, and drivers with a navigation system that included traffic", and all participants were people who had not used a GPS navigation device before. Read on to find out what they discovered...
Photo: Flickr, CC
From Navteq (via Jalopnik):
the results revealed that the drivers using navigation devices 1) drove shorter distances and 2) spent less time driving. Conducted in two metropolitan areas of Germany - Dusseldorf and Munich - the study also showed that drivers with navigation devices had a 12% increase in fuel efficiency, as measured by liters of fuel consumed per 100 kms. Fuel consumption among those drivers using navigation fell from 8.3 to 7.3 l/100kms. When the study results are annualized, they equate to a nearly 2500 kilometer drop in distance driven per year per driver, and an average of euro 416 in savings on fuel annually per driver. [...]
The study results reflect more than 2,100 individual trips, more than 20,000 kilometers and almost 500 hours on the road.
Another interesting find: There's a learning curve, so you actually see bigger reductions in driving time (and thus in fuel consumption) after drivers have had some time to get more familiar with the GPS navigation systems ("greater decreases in trip times and distance driven were seen in the latter half of the study").
Also, devices with real-time traffic information made a bigger difference during rush hour (duh).
Now of course 12% is an average. I suspect that for some people who have a tendency to get lost easily, and to drive around a lot looking for things, a nav system could make a bigger difference, while expert drivers who know exactly where they're going and know all the tricks to avoid traffic might not see as big a drop in fuel consumption.
Best trick still is to avoid driving in the first place, but if you have to, a GSP nav system (especially if you keep it many years and don't buy a new model too frequently) could help reduce your fuel consumption and be worth it from a green perspective.
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