DETROIT - Quiet hybrid vehicles may pose risks to pedestrians, the head of the National Highway Traffic Safety Administration (NHTSA) told attendees at the Society of Automotive Engineers (SAE) World Congress April 15, according to the Detroit News.

David Strickland, the new NHTSA administrator, also raised concerns about in-vehicle entertainment systems that could distract drivers.

"A quieter fleet could potentially put pedestrians at risk, especially blind pedestrians," Strickland said.

According to Strickland, the NHTSA is currently conducting a research program on quieter cars and the safety of blind pedestrians. "Our analysis of limited data from 12 states shows that hybrid electric vehicles do have a significantly higher incidence rate of pedestrian crashes than internal combustion engines for certain maneuvers -- like slowing or stopping, backing up, entering or leaving a parking space, and making a turn," he said.

NHTSA is working on the second phase of its research project to assess requirements for vehicles to "emit a base level of sound at low speeds to provide some level of identification to pedestrians that a vehicle is approaching," Detroit News reported.