Dedicated navigation devices such as those from TomTom and Garmin could be on the way out, according to ComScore.
In a European survey of cellphone users, the company found that more than 21 million users were using their phones for navigation, up 68 percent from last year.
Most - 68.2 percent - say they use the service in a car or other vehicle, compared to 35.3 percent on public transport and 27 percent while walking, running or cycling.
Those with assisted GPS (A-GPS),advanced positioning technology are more than eight percentage points more likely to use maps in a vehicle.
"The higher incidence of A-GPS usage in cars suggests that the superior speed and precision in these devices are being used for more than just identifying locations – they are being used as full in-car navigation systems," sais ComScore senior analyst Alistair Hill.
Hill says he believes the main reason cellphone navigation apps are taking over is the price - many offer just as much functionality as standalone devices, and cellphone vendors such as Google and Nokia are increasingly offering the functionality for free.
"Mobile mapping services also have potential for integration with other location aware services, such as mobile social networking applications that provide links to friends and insights on surroundings and, subsequently, offer great promise for the location-based advertising market," he says.