But the proliferation of mobile devices such as smartphones means "we have the opportunity to give consumers better and more relevant data to understand what they can expect in on-the-road fuel economy performance," said Jim Farley, Ford executive vice president for global marketing, sales, service and Lincoln, during a speech at the New York auto show last month.
"We need to help customers understand the concept of personal fuel economy—based on their own individualized experiences—and give them tools to see, learn and act upon all the information available to know what to expect, how to improve" their driving, Mr. Farley said.
More readily available and comprehensible information could even "offer guidance in their shopping process," he suggested.
Car makers that figure out the best ways to help consumers measure their real-world fuel economy could enjoy a competitive advantage, Mr. Farley said.
Real-world fuel economy has become an industry hot-button topic as car makers make competing ad claims about the mpg ratings of their fleets. Mr. Farley noted that the fuel economy of hybrid vehicles seems particularly variable depending on consumers' driving habits. Ford has a growing number of hybrids and plug-in hybrids arriving in showrooms, including the 2013 C-Max Energi and Fusion Hybrid.
Auto makers often tout vehicles' EPA fuel economy ratings in ads and marketing materials, but that can backfire when real-world numbers don't match the lab results on which the EPA relies.
In December, Consumer Reports magazine said two Ford hybrid nameplates fell 17 percent to 21 percent short of the auto maker's promise of combined city/highway 47 mpg in the tests. The Ford Fusion Hybrid achieved 39 mpg and the C-Max Hybrid averaged 37 mpg, the magazine said.
To lure app developers interested in entering the contest, Ford is offering access to a portion of its computer database.
Mr. Farley said the company will open its "OpenXC connectivity research platform as a sandbox" for developers to "create and test innovative ideas."
In 2011, Ford and a software company named Bug Labs joined to create OpenXC as a standard way of creating aftermarket software and hardware for its vehicles.
"Every new car is full of computers and electronics, and there is growing interest in connecting the output from those systems to third-party applications and the Web," says an explanatory note on OpenXC.com.
Using a small hardware device, the OpenXC platform can pull data from a vehicle's onboard diagnostic port, which is standard on every vehicle below the instrument panel to the left of the steering wheel. Onboard computers collect a vast array of performance data, including the engine's revolutions per minute, fuel consumption, accelerator and brake pedal usage and steering wheel angle.
To use a hypothetical example, an app that pulled and crunched that data then could tell a driver: "Jack, you were driving very aggressively last week. If you had backed off just a little, you would have consumed two fewer gallons on your commute last week."
Consumers could compare notes with their friends on how efficiently they had been driving.
A Ford spokesman said the company has not decided what it will do with the proposals that developers enter in the contest. "It's about trying to spur innovation," he said. "We want to have a contest and a prize to show that we appreciate developers' time and effort in helping us come up with innovative solutions."
This report appeared in Automotive News, a Detroit-based sister publication of Tire Business.