MILAN/STOCKHOLM, July 15 (Reuters) - A survey of transport industry experts has shown that drivers' misuse of driver assistance technologies and their distraction by in-vehicle features are the biggest threat to road safety, not mechanical problems.

The survey, published Wednesday, reflects industry concerns about human error at a time when some governments are considering imposing stricter regulations on automated driving systems.

In the United States, concerns are growing about the features offered by automakers, including Ford’s Blue Cruise semi-autonomous driving system and Tesla’s full self-driving system.

Ignacio Alvarez, head of research and development at Brembo, the Italian brake manufacturer that funded the survey, said, "We need to make sure that these systems are clearly explained to the end user, with an explanation of what they can and cannot do."

The survey, conducted by The Economist Enterprise, a division of The Economist Group, included more than 1,000 transport professionals in the areas of public policy, infrastructure, manufacturing and technology in car-producing countries such as France, Germany, Italy, the United Kingdom, China, India, Brazil, Japan, South Korea and the United States.

Pratima Singh, head of research at the Economist Enterprise, said, "The real danger lies in the interaction between humans and increasingly automated machines and systems."

Thirty percent of the transportation professionals surveyed cited human misunderstanding or misuse of driver assistance systems as the primary cause of safety problems, while 24 percent, in a separate question about safety risks arising from user-vehicle interaction, pointed to increasingly distracting features within the vehicle.

Singh said that two-thirds of specialists believe that advertisements exaggerate the capabilities of these systems, "creating unrealistic expectations."