Construction crews began tearing down the 83-year-old bridge over Roop Branch on Watson Lane last week. The project will block through traffic on the 1 1/4 -mile road off Route 75 between New Windsor and Union Bridge for three to four weeks.
In place of the bridge, two corrugated metal pipes will channel the stream under the road.
School buses, which will have to turn in a driveway near the western edge of the bridge and use Pipe Creek Road to reach Francis Scott Key High School or return west on Watson Lane to New Windsor Middle or Elmer Wolfe Elementary School, are expected to be most affected by the work.
There are no houses on Watson Lane east of the bridge, where Roop Branch meanders through a pasture. The road serves about 25 houses west of the bridge.
The construction "added maybe five minutes" to four school bus runs, said Philip Martin, assistant in pupil transportation with the county school system.
Mr. Martin said three buses use Watson Lane for four bus runs: elementary, middle and high school, and a midday kindergarten run.
Mary E. Stong, principal of Elmer Wolfe Elementary School, and Jeffrey L. Kimble, principal of New Windsor Middle School, said they hadn't noticed any impact or heard any comments from parents.
The bridge was put on the State Highway Administration's replacement list after engineers found that it was deteriorating. "Eighty-three years is pretty old for a bridge," said SHA spokeswoman Valerie B. Edgar.
The Watson Lane bridge is one of 15 in Carroll, Howard and Frederick counties being repaired or replaced under a $925,000 contract.
Other projects in Carroll County include replacement of the bridge over Big Pipe Creek on Route 140 and repair of the Liberty reservoir bridge on Route 26.