New GPS units not just for directions

Millions of Americans have finally traded the folded gas station map in the glove compartment for a handy Global Positioning System unit.

You know, those small doohickeys that communicate with satellites hovering above the Earth to pinpoint your location. With built-in maps for the entire United States (and, usually, most of North America), GPS navigation units can help you reach your destination with turn-by-turn visual and audio instructions.

GPS also offers millions of relevant points of interest, such as restaurants, gas stations, hotels, ATMs and tourist attractions. And if you get lost, a GPS device will recalculate how to get back on track.

Now, there are a host of impressive features for these mobile gadgets to make them work even better.

So if you're shopping for your first — or next — GPS unit, consider the following five features (many devices will have two or more):

• Garmin Nuvi 660: Real-time traffic alerts. New GPS devices can alert you to traffic issues so you can avoid them. But the service usually requires an annual service fee (of about $60 a year) to get the real-time updates. Plus, it's available only in select cities throughout the USA, Canada, Australia and New Zealand.

A small antenna gets data via FM frequency, so you can be warned of traffic backups. The Garmin Nuvi 660 ($749.99 at www.garmin.com, but you can find it, and other products mentioned here, for less if you shop around) includes this integrated traffic receiver and a 90-day free trial.<

• Mio DigiWalker H610: Built-in battery. GPS devices once were limited to the vehicle where they were used, either because they had a non-removable in-dash design or required power from the car's cigarette lighter. Now, many GPS devices offer a rechargeable internal battery, which means you can easily use it in any vehicle — or even on foot. The Mio DigiWalker H610 ($199.99; www.mio-tech.com) is smaller than a bar of soap (2.32 inches by 3.35 inches by 0.74 inches). It also offers pedestrian and cycling maps, so it won't tell you not to walk the wrong direction on a one-way street.

• TomTom One XL-S: Text-to-speech translation. Many new GPS devices, such as the TomTom One XL-S ($299.95; www.tomtom.com) include a handy "text-to-voice" feature. So, instead of the machine telling you "turn right in 1 mile," it will say something more specific, such as: "turn right in 1 mile on Alphabet Street."

Many people prefer to hear the name of the road read aloud, rather than having to look for it on the GPS map or street sign. For $499.95, the TomTom Go 920 also lets you say the destination address out loud rather than type it in.