Baltimore's Central Light Rail Line spares the region's streets and highways an average of 5,000 cars each weekday, a volume of traffic equivalent to an extra lane of rush-hour commuters on the Jones Falls Expressway.
The conclusion is based on the results of a one-day survey of nearly 4,000 light rail passengers conducted by the Mass Transit Administration and the Baltimore Metropolitan Council. Their report, released last week, is the first comprehensive look at the 26-month-old system's estimated 18,600 daily passengers.
The survey found that 22 percent formerly drove to work and that 46 percent said they have a car available, but prefer to ride light rail. MTA officials describe those results as better than expected.
"That is a significant number of cars taken off the road," said John A. Agro Jr., the MTA administrator. "It shows that the benefits of light rail have extended to people who don't yet ride the system."
The majority of light rail riders, 52 percent, previously traveled by bus. While that shows a majority of customers merely went from one mass transit system to another, more expensive one, industry officials say Baltimore's experience reflects the normal pattern.
"When parallel bus lines are discontinued and customers are redirected to light rail, you're going to have that kind of result," said Charles O. Bishop, spokesman for the American Public Transit Association in Washington. "The rail line becomes equivalent to an express bus service."
An estimated 70 percent of riders use light rail to commute to or from work.
The survey indicated that a majority of riders live within two miles of a stop. About 35 percent take the bus to a light rail stop, 33 percent drive, and 23 percent walk. To reach their ultimate destination after their train ride, most passengers either walk or transfer to a bus.
Women riders outnumber men 53 percent to 47 percent.
The report notes that three-quarters of riders are between the ages of 20 and 49.
The riders represent a wide variety of income levels and educational backgrounds. For instance, one-third earn more than $40,000 a year, while a third earn less than $20,000 a year.
A majority of patrons avoid the ticket vending machines by buying weekly or monthly passes.
The most popular stations for boarding are Lexington Market, Cherry Hill, University Center, Cromwell Station and Timonium, in that order. The least-used are Ferndale, Nursery Road and Linthicum, all in Anne Arundel County.
When riders were asked to comment on the system, positive sentiments outnumbered negative by a 2-to-1 ratio.
The most common response was a request for improved service or expansion of the system.
The survey was conducted Nov. 16 from 6 a.m. to 3 p.m. when riders were asked to complete a one-page form.
Since last year, MTA officials have revised their estimate of average daily ridership to about 21,000 -- an estimate based on fare revenue.
The new estimate does not include baseball patrons. If Orioles baseball games are factored in, the MTA calculates daily light rail ridership at about 23,000.
The MTA's stated goal for light rail is to attain an average 33,000 daily riders by 2010, assuming the completion of planned extensions to Hunt Valley, Pennsylvania Station and Baltimore-Washington International Airport.
"We are better than two-thirds to our goal and will certainly reach that number before the year 2000," Mr. Agro said.
One of the factors limiting further growth is a lack of parking at stations. At the time of the survey, three station parking lots were full, and the lots at Timonium, Cromwell Station and Patapsco Avenue were the only ones with significant numbers of empty spaces.