Apple has been contemplating a close pairing between iPhones and some cars when it comes to GPS navigation, a recent patent application hints. While limited navigation apps have been possible since the introduction of the iPhone 3G, and proper turn-by-turn apps have become possible with the iPhone 3.0 firmware, the Apple patent proposes linking an iPhone into a car's navigation system, which in turn could pull information from the main car computer.

Some details read by an iPhone could include speed, fuel consumption and brake application. The result would be a more precise estimate of travel time, based on more than just distance and average commutes. iPhones could also tap into a dedicated navigation system's traffic service, gaining real-time data on the impact of construction and congestion.

Such technology could be aided by iPhone 3.0, which is able to more directly communicate with third-party hardware. At the same time it would require integration on the part of car or navigation system makers, and could be rendered irrelevant by the existence of software such as TomTom's iPhone app. High-grade mapping and traffic data may leave little incentive to pair with a car's computer.