The State Highway Administration is taking another crack at the Towson roundabout — aiming to improve safety and traffic flow at an intersection that has bedeviled engineers for decades.

The agency said it will launch a $632,000 project at the roundabout in the heart of the downtown area Tuesday, requiring a series of lane closings that will continue through late summer.

The SHA said this round of work, unlike previous projects, is not intended to fix something wrong but to make permanent some of the changes it got right in 2008.

"Basically, this is the final version of the improvements we did in 2008," said Fran Ward, SHA District 4 community liaison.

Ward acknowledged that the agency has made numerous tweaks to the design of the roundabout since it opened in 1998 at a complicated intersection that was the scene of congestion and many crashes when it was controlled by signals.

She said the 2008 work used temporary measures such as reflective paddles and temporary curbs so highway engineers could study how the changed traffic patterns functioned through different seasons. Now, Ward said, after two years of observing the effects, the agency is satisfied that the changes should be made permanent.

The new phase of the project will include upgrades to pedestrian crosswalks, relocation of gutters and sidewalks, and installation of concrete curbs. Finally, the highway agency will resurface the roundabout and paint new lane markers.

The SHA said the work will take place at night and will not affect daytime commuters. Lane closings will occur from 9 p.m. Sunday through Thursday until 5 a.m. the following morning. According to the agency, the work will be done in six phases, including five that will correspond with the five legs of the roundabout — East Joppa Road, Dulaney Valley Road, York Road north, York Road south and Allegheny Avenue/West Joppa Road.

Not everybody is happy with the changes.

Todd Zeigler of Rodgers Forge said he seldom patronizes businesses in the area because of the roundabout. He said he used to like the traffic flow there before traffic engineers permitted daylong street parking on York Road and narrowed parts of the traffic circle from two lanes to one.

Zeigler said that before he moved to Maryland he was municipal manager of Spring Grove in York County, Pa. He said Spring Grove officials who visited Towson came away so impressed that they installed a roundabout at a difficult intersection in their community.

But that was before the 2008 redesign.

"The functionality has taken a step back with their changes," he said. "I don't think it's an improvement."

michael.dresser@baltsun.com