WASHINGTON -- Experts say motorists can save money on gas by slowing down, but, as one Maryland man found out, that may not always be a good idea.

Glenn Conrad said his Honda hybrid usually gets about 70 miles per gallon, but he feels great if he can get 80 miles per gallon or more.

Conrad admitted he is what's known as a "hyper-miler," someone who stretches his or her car's miles per gallon by altering his or her driving habits.

On June 12, Conrad was "hyper-miling" on Interstate 95 on his way to Baltimore/Washington International Airport. He said his car would roll down hills at up to 65 mph, and he would tap the gas until it reached 55 mph going uphill or 50 mph just puttering down the road.

Conrad said he was surprised when a Maryland State Police trooper pulled him over.

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The trooper asked Conrad why he was driving 50 mph. Conrad said he was saving gas.

The trooper, however, was more concerned with motorist safety and issued Conrad a warning for driving 15 mph under the posted speed limit.

"Speed limits aren't just put there just because the state decides what they want," said Maryland State Police Sgt. Chris Davala. "It's because of fuel conservation and the safety of the other motorists and the motorists around you on the highways."

AAA officials agreed that driving too slow can be a hazard.

"The optimum speed for saving gas is probably 55 or a little above that right now, so the thought that you're saving more gas by driving 50 or 45 on high-speed roads isn't accurate, and it's very, very dangerous," said AAA Mid-Atlantic spokesman Lon Anderson.

Conrad said he won't go 50 mph on I-95 again -- he'll drive 51 mph.

According to Maryland driving laws, slow speed impeding traffic is prohibited. Troopers have discretion to pull over motorists if they feel they are creating unsafe driving conditions---by driving too slow.