Tired of wrestling with road maps or being late for appointments because you can't find an address? You might want to consider opting for a factory-installed navigation system in your next vehicle.

Once an option only in luxury cars, factory-installed navigation systems are standard in many top models and available as an option in a variety of less-expensive vehicles. Factory-installed navigation systems average about $2,000 but often are grouped with other accessories in higher-priced option packages.

Navigation systems use Global Positioning System satellite signals to determine the vehicle's location and compare that information with map data stored in the system's onboard computer. When you enter a destination, the system uses its map data to determine the best route. Most systems can direct you by showing the vehicle on an LCD map display on your dashboard, or by voice commands that play through your car's sound system.

Many systems require you to enter data manually from a touch-panel display (some allow data entry only when the car isn't moving) while others use speech-recognition technology and can understand dozens of simple voice-activated commands such as “Find nearest gas station” or “Find nearest Chinese restaurant.”

Built-in navigation systems usually are much more accurate than add-on systems because they hook into your vehicle's instruments to determine speed, mileage and other information. However, they come at a higher cost, with on-going costs to update the maps in many cases.

But even the best navigation systems aren't totally accurate. Some do a better job at providing directions than others. Most systems guide you along main roads, even if that may mean a slower trip because of traffic lights or rush-hour jams. In addition, even up-to-date navigation software can't account for every new street, exit or shopping center.

You'll want to check out reviews of navigation systems. While features such as real-time traffic and weather are nice, not all nav systems are intuitive or easy to use - and they certainly don’t all work the exact same way. Studies show younger buyers tend to use them more often, and each year these systems become increasingly sophisticated as technology rapidly advances. A few are now being integrated with vehicle safety systems or feature handwriting touch recognition technology.

Some considerations when deciding to purchase a navigation system (unless it’s standard on the models you’re shopping) should include ease of use, frequency of use, distraction/safety concerns, cost of map updates, system features, map readability and effect on potential resale value of the car.

Lastly, in addition to other portable navigation devices that are available (costing much less than factory installed systems), as smartphone capabilities progress companies like Google are offering free mapping with turn-by-turn navigation apps. Other popular apps include Skobbler and MapQuest.