Apple displays the CarPlay program at the Worldwide Developers Conference in San Francisco, California June 2, 2014. (Photo: REUTERS)

A new feature quietly unveiled at Apple's developer conference this month will allow CarPlay users to tap an app to navigate to a pump and buy gas straight from a screen in the car, skipping the usual process of inserting or tapping a credit card. Details of Apple's demo for developers have not previously been reported.

Fuel apps are just the latest in a sustained push by Apple to make it possible to tap to buy from the navigation screen. It has already opened up CarPlay to apps for parking, electric vehicle charging and ordering food, and it also is adding driving task apps such as logging mileage on business trips.