Experts in the autonomous vehicle field are finding a challenge in answering one question: should self-driving vehicle makers create their own maps?

Google Inc., for example, reportedly is creating detailed maps. Egil Juliussen, an analyst with IHS Automotive, is quoted in a news story by Reuters as saying that mapping the entire U.S. to the level of detail used by Google's cars could cost hundreds of millions of dollars and take five to seven years.

Raj Rajkumar, an expert on self-driving cars at Carnegie Mellon University, says that map-based approach is sensible for a company with Google's resources but is not required.

“Google is capable of collecting all this information. In our case, we don't have that capability, so we have to be creative. It turns out that's sufficient." says Rajkumar. He developed a modified Cadillac that uses radars, video cameras and six laser scanners. In 2013 the vehicle drove 33 miles (53 km) without human intervention or 3D maps, the Reuters article says.

While autonomous cars rely on basic electronic maps for navigation and maneuvering in lanes, Google's cars use more detailed 3D maps, created by laser scanners. Google then analyzes the data and determines where stop signs and traffic lights are. This enables the vehicle to know its exact location.