(MediaBuyerPlanner) With more consumers purchasing global positioning systems, marketers have begun exploring GPS devices as an advertising tool, Brandweek writes.

Two months ago, Dunkin' Donuts, Cold Stone Creamery and others started alerting drivers to nearby locations and offering special deals via in-car GPS devices.

"Not only can GPS devices tell you how to get there, they can tell you where to go," said Samir Bhavnani, Current Analysis's director of research.

Although GPS users total well under a million, unit volume sales of the devices jumped 152 percent in 2005, per NPD Group - which doesn't include Wal-Mart, direct and warehouse clubs sales.

Ross Rubin, director of industry analysis at NPD, said GPS advertising has "huge potential . . . to almost literally drive traffic to the point of transaction."