Are We Lost Yet?
By Kevin Clemens
Versatility is the biggest advantage of on-dash navigation systems. They are easy to move from vehicle to vehicle and can be placed in a rental car while on business or vacation. Most systems have some sort of suction cup or weighted mount for the windshield or dashboard, and a power cable to attach to the vehicle's 12-volt power outlet. Care must be taken to make sure that these units are not mounted directly in front of the passenger-side airbag, since airbag deployment during a collision could propel the unit into a passenger's face.
Some of these systems have external antennas with magnetic mounts that can be placed outside of the vehicle for better satellite reception. Most portable systems have small screens and "tinny" speakers, but their portability makes up for these minor annoyances. Prices vary widely for these systems, but so does convenience, readability and performance.
Portable Systems for Laptops and PDAs: Advantages
If you travel with a laptop or one of the more sophisticated PDAs, you might want to look at adding a GPS module to handle your in-vehicle navigation. The advantage of using a laptop comes from its large screen size and reasonable audio quality. The main disadvantage is that you have to securely mount the laptop somewhere in the vehicle - usually on the front-passenger seat. Taking your eyes away from the road to look at your computer also can be hazardous.
PDAs, on the other hand, can be placed in a dashboard mount, and some GPS modules even connect via a wireless interface to the handheld computers. In addition, external antennas are available for some of these laptop computer and PDA-based systems. PDA screens are small in size and their speakers aren't very good, so some of the same problems of portable on-dash systems are found when using a PDA as a navigational tool.
No matter which system you use, you'll find that almost every road and highway in the U.S. has been stored onto digitized maps. You may still find a dirt road or trail deep in the country that has not been digitized, but these days that is rare. In general, navigation maps come stored on CD-ROM or DVD-ROM storage media.
Most CD-based systems cover only a few states. You may need to buy up to 10 CDs to cover the entire United States. DVD-based systems cover more territory but are usually available only for in-dash systems. Some DVD systems also require fees to be paid to "unlock" other regions.
A few portable systems use internal hard drives to store maps and information about roadside attractions. These can usually be updated through flash memory or by interfacing with a home-based computer system and downloading information off a Web site.
Words of Caution
Although in-vehicle navigation systems can be useful, and can even improve driver safety, they can also provide a dangerous distraction. While most in-dash systems have a lockout feature to prevent the driver from entering a new destination while the vehicle is in motion, portable and PC-based systems generally do not. It is extremely unsafe to be operating your laptop, trying to enter a destination or boot-up a navigation program, while driving. Obviously, you should handle all of these operations while on the side of the road or in a parking lot before heading out onto the highway.
In addition, although most of these on-board navigation systems do a pretty good job of getting you to your destination, they are not foolproof. Roads change, two-way streets become one-way, and your local knowledge can almost always beat the computer's best guess at the most appropriate route.
Even with a navigation system and the latest digitized maps on DVD, you may still be tempted to pull out an old-fashioned road map. And instead of the soothing synthesized voice of your navigation system, you can have a more lively discussion with whomever you're driving with!
Kevin Clemens has both undergraduate and graduate degrees in engineering and has authored several patents. A former Product Public Relations Director for Michelin Tires and Technical Editor at "Automobile Magazine," Kevin writes for "European Car" and other publications when not competing in rallies in various parts of the world with his vintage automobiles.