Thanks Jay. Navigation systems have helped a great deal but there is something few people know about them. Many of them operate off of cell phone towers. Now that there are so many towers and technology has advanced they can triangulate your location based off what tower your phone is operating off of. This is way cheaper than satalites.
If the towers quit working your GPS may not work as well as you would like. Depending on the situation the government could also block civilian use of satalites making true GPS systems useless. Those are the reasons I recommended driving and knowing your exit routes ahead of time. Never be totally dependant on tech.