PARSIPPANY, N.J. -- Avis Rent A Car and Motorola have completed their nationwide rollout of "Avis Assist" -- a mobile phone-based navigation system now available in 57 U.S. cities.

Powered by Motorola's VIAMOTO software, Avis Assist lets customers instantly access verbal directions from a Motorola handset. The handset can be mounted easily in the car or carried in the customer's pocket.

"Since we first introduced Avis Assist late last year, consumer acceptance has exceeded our expectations," said Scott Deaver, executive vice president of marketing for Cendant Car Rental Group, the parent company of Avis. "The fact that Avis Assist can be used in conjunction with any vehicle is proving to be especially attractive to our renters. This confirms our belief that drivers not only want GPS service, but also seek mobility, speed and ease of use to reap the benefits."

To map out a route, travelers simply contact the call center for a live Avis advisor or input their destination through the phone keypad. Once the destination is received, the VIAMOTO system calculates a route, downloads it from a server to the mobile handset, and begins pinpointing the traveler's location to ensure accurate directions.

As soon as the car begins moving, street-specific directions are communicated through the handset's speakerphone. If the traveler takes a wrong turn, the system knows it and will recalculate the route.

"Directions and navigational applications are among the top requests for mobile consumers," said Neal Campbell, general manager of location services for Motorola.

One-third of all U.S. wireless users are interested in receiving location-based information such as driving directions, according to the Yankee Group, a leading consulting company. "VIAMOTO and Avis are together meeting an acute need in the market," said Eugene Signorini, wireless analyst with the Yankee Group, "while solving problems for people on the go."

The latest additions to the roster of cities offering Avis Assist are Seattle, Houston and Honolulu.

Motorola and Avis plan to expand the Avis Assist suite of offerings to include real-time traffic updates and alternate routes, as well as Amber Alert notices, later this summer. In addition, Motorola's VIAMOTO solution will offer users the ability to receive information on local restaurants and schedule reservations, receive updates on event listings, and identify areas of interest such as the closest ATM.

Avis Assist units can be rented with any Avis vehicle at available locations for an additional $9.95 per day.