The Metropolitan Police Department has unveiled a new vehicle that will be used in the police effort to step up enforcement of alcohol and speed traffic laws and, at the same time, save the department valuable manhours now used in provessing drunken drivers.

The new vehicle, known as an "Alcohol and Speed Enforcement Mobile Test Van," also will allow the department to start a new program designed to speed up arrests of drunken drivers. Funds to purchase the van for $29,700 came from the U.S. Department of Transportation as an award by the National Highway Traffic Safety Administration for reducting alcohol-related traffic fatalities for the last three years.

The van, which the department put into action recently, operates on two shifts, from 10.30 p.m. to 3 a.m.

According to Capt. Wayne A. Layfield, head of the police traffic department, it takes about an hour and a half to process a routine drunken driving arrest. Layfield said the van is able to respond to an arrest, take over the arrest procedure and allow the arresting officers to return to patrol.

The Metropolitan Police Department is the only large city police force of its kind to have such a unit. The van, about the size of an ambulance, has a holding facility for persons arrested and spaces for three officers.

Funds for the van were part of a $186,000 grant through the U.S. Highway Safety Promgram Coordinator. The grant was to be split between the police traffic division and the D.C. Department of Transportation. The remainder of the ufnds for the police department will be sued to increase enforcement of speeding and jay walking laws.