Data confirm slowing of morning commute

High-tech devices plot decline in traffic speeds between 7 a.m. and 9 a.m.

October 15, 2003|By Alec MacGillis | Alec MacGillis,SUN STAFF

Confirming with high technology what many Baltimore-area commuters know from experience, a study has found that traffic congestion worsened considerably on the Beltway and other key stretches of highway in the region since 1998.

The Baltimore Metropolitan Council used Global Positioning System and Geographic Information System technology to track driving speeds during the morning rush hour, from 7 a.m. to 9 a.m., in the fall of 1998 and again in the fall last year.

Researchers found that average speeds for all seven freeways surveyed stayed steady, at 59 mph, over the four years. But traffic slowed noticeably - by as much as 15 mph - on several key approaches into and around Baltimore.

Among the stretches with the greatest slowdowns were southbound Interstate 95 between the Beltway (Interstate 695) and the Fort McHenry Tunnel; the inner loop of the Beltway between Interstate 795 and the Jones Falls Expressway; and the outer loop of the Beltway between I-95 and Providence Road. Average morning commute speeds on those routes fell by 12 mph to 15 mph.

Also experiencing greater congestion were southbound Route 29 between Interstate 70 and Route 100, where the average speed plummeted 17 mph, and the outer loop of the Beltway between I-795 and I-95 in Arbutus, where average speeds fell 7 mph.

The researchers said yesterday that while the trouble spots were not surprising, the magnitude of the slowdowns underscores that congestion has become a serious problem for the Baltimore area.

"What we're seeing is that congestion continued in areas that experienced it previously, but may have gotten worse because of factors of where people live and where people want to go," said Harvey S. Bloom, director of the transportation division at the council, which advises the governments of Baltimore and the surrounding suburban counties.

Reports of worsening traffic in the area are not new. But never before, say the study's authors, has anyone been able to pinpoint the problem so precisely.

To determine speeds, researchers gave GPS units to commuters and instructed them to maintain the average speed of the general traffic by passing one car for every one that passed them.

Speeds were measured in the fall months to avoid flukes caused by summer and winter vacation or holiday traffic. Data was not collected on bad weather days.

In all, speeds were measured on 42 heavily traveled corridors of both highways and "arterial" roads, busy routes with stoplights.

"The other methods that have been used don't seem as accurate," said Victor Henry, the council's data management coordinator. "This leaves less up to human error."

The authors offered possible explanations for some of the areas suffering the greatest congestion. In general, they said, many trouble spots probably resulted from population growth in Carroll and Harford counties, as well as the growth of employment centers in central Baltimore County.

They attributed the slower speed on the Beltway's outer loop from I-795 south to I-95 partly to the widening project started in the spring of 2001 and its resulting lane shifts during rush hour.

The slowdown on the inner loop headed the other way, from I-795 to the Jones Falls Expressway, may be due partly to commuters seeking an alternative route to downtown Baltimore to avoid the widening work, the authors suggested.

The 12 mph decrease in average speed on I-95 southbound from the Beltway to the Fort McHenry Tunnel was attributed partly to bridge deck work from the I-95/Interstate 895 split south to the tunnel, work that resulted in lane shifts but no closures in the morning rush hour.

Byron N. Johnston Jr., a spokesman for the Maryland Transportation Authority, which manages that stretch of I-95, said the agency had recognized that repair work was slowing the morning commute, but the work was needed. He noted that officials are considering toll increases for tunnels and bridges to pay for further upgrades on that corridor.

Not all areas suffered worsening congestion. Route 32 eastbound between Route 108 and Interstate 97 saw its average speed increase by 13 mph, an improvement attributed to the opening of the parallel Route 100 in December 1998.

Advocates for commuters said the report shows the need for expansions of the clogged corridors or the creation of alternative routes.

"The biggest challenge ahead is finding ways to fund and increase new capacity," said John White, a spokesman for the AAA's Mid-Atlantic chapter. The auto club spokesman said he hopes the study encourages more public transit use among those living in areas north and northwest of the city that are served by commuter rail - areas that are driving much of the congestion.

Will Burns, a spokesman for the Maryland Chamber of Commerce, said he hopes that congestion identified by the study would be addressed by a commission appointed by the governor last year.

"This is a top priority heading into the [legislative] session," Burns said.

The study's authors said they would present their data to the Baltimore Regional Transportation Board, which could use the report to prioritize construction projects. In the short term, they said, commuters could use the findings to make decisions about how to get to work faster.

"People are developing behavior based on where they see the capacity exist," said Bloom.

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