KENT, Ohio (AP) -- A weather researcher suggests in a new study that when a tornado hits it's safer to stay in a car than hide in a ditch.

"Ditches are outside, and outside is dangerous during a severe thunderstorm. ... A person is exposed to flying debris, lightning," said Tom Schmidlin, chairman of the Kent State University geography department.

Schmidlin is challenging guidelines of the National Weather Service and other groups that advocate getting out of cars or mobile homes and lying in a ditch if no shelter is nearby.

"A person lying in a ditch is stuck in a bad situation, but in a vehicle you have the opportunity to move to a sturdy shelter," he said.

Curtis Carey, spokesman for the National Weather Service, said the published research in the December issue of the Bulletin of the American Meteorological Society has prompted a review of the agency's tornado safety standards.