Passage Summary: Using a GPS is better for the environment and safer for drivers because it finds shorter routes and allows drivers to stay focused on the road instead of fumbling with maps.

Conclusion: Satellite navigation systems save fuel and improve driving safety.

Reasoning: Drivers using these systems drove fewer miles on average than those using maps, and they were able to keep their eyes on the road instead of looking at paper maps.

Analysis: To strengthen this argument, we want to bolster the link between using the device and the positive outcomes of fuel efficiency and safety. We should look for an answer that eliminates a potential downside, such as the idea that the devices themselves might be a distraction. If we find out that the fuel saved by driving fewer miles isn't offset by, say, the satnav leading people into heavy traffic, the argument becomes much more robust. Look for an answer that confirms these benefits aren't just a fluke of the specific study mentioned.