The popular "Baby on Board" signs that are appearing on the windows of vehicles all over the country may be the hottest selling automobile accessories on the road, but Washington area police officials say they could bring a fine up to $30.

The plastic signs, which cost about $1.50, are usually placed on rear or side windows with a suction cup, and are an apparent plea to fellow motorists to drive more safely for the sake of young passengers.

Now the "BABY ON BOARD!" signs have spawned parodies in recent months, as other motorists began displaying signs with sayings such as, "HUNK ON BOARD," "NOBODY ON BOARD," "EX-HUSBAND IN TRUNK" and "CAT IN GLOVE COMPARTMENT."

Local traffic enforcement officials are not amused. They say that regardless of the purpose of the signs, they are an infraction of the law.

In Maryland and D.C., which have similar laws, motorists caught with the signs could receive traffic tickets for "obstructing vision," which carry fines of $25 and $30.

District and Maryland laws forbid the operation of vehicles " . . . with any sign, poster, card, sticker, or other nontransparent material in the windshield, side wings, or side or rear windows."

In Virginia, the signs are permitted if the car has dual rear-view mirrors. On cars without dual mirrors, the size of any sign in a window can be no larger than 4 by 5 inches, state police officials said.

Last week, the Maryland attorney general's office sent a memo to all police agencies in the state to remind them that the signs are a traffic violation, but said officers should use their discretion in issuing tickets.

Sgt. Thomas Brightwell of the Montgomery County police traffic branch said the signs probably do more harm than good. "People with these signs are going overboard," he said. "A lot of the signs I've seen don't even relate to safety, and the position they're mounted in could totally block the driver's view."

In Prince George's County, police spokesman Bruce Gentile said drivers with the signs can receive a $30 fine, and one point assessed against their driving record.

Local police officials said they have not increased enforcement against motorists who display the signs, and no records are available on the number of citations that have been written.

Harold Lorsch, president of a California-based company that sells the signs, said a warning to consumers that the signs should not be placed in an area that obstructs their view has not slowed his business. He said his company has sold at least 10 million signs in the past three months.

"I think the laws are crazy." Lorsch said. "Maybe that's because I manufacture them, but people are just having fun. Why spoil it?"