By Jerry LaMartina
The Mission City Council will consider spending about $8,000 for a traffic study to determine whether a protected left-turn signal is warranted for southbound traffic on Broadmoor Street turning east onto Martway Street.
The council’s Community Development Committee decided at its Wednesday meeting to forward a recommendation for the study to the council as an action item for the council’s Jan. 18 meeting.
A new traffic study would serve dual purposes because a traffic study is required in order to get County Assistance Road System (CARS) funding for Broadmoor from Johnson Drive to Martway, Public Works Director John Belger said. Johnson County’s CARS program pays half the cost of construction and construction inspection for eligible projects.
Olsson Associates conducted a traffic study in early 2011 and determined that a left-turn signal at Broadmoor and Martway wasn’t warranted and that a new signal at Woodson and Johnson Drive also wasn’t warranted. The committee also rekindled discussion Wednesday about whether to install a signal at that intersection, which would cost about $150,000. A signal at that intersection was removed several years ago as part of the Johnson Drive project.
City Administrator Laura Smith said that installing an unwarranted traffic signal at Woodson and Johnson Drive several years ago could have jeopardized almost $2 million in federal funds for the Johnson Drive project.
Smith cited the Manual of Uniform Traffic Control Devices as the best guide for adding, removing or otherwise changing traffic signals and urged committee members to become familiar with it.
“It’s sort of the bible for traffic engineers and traffic-engineering work,” she said. “It really is the guiding document for design, installation, management, operation and maintenance of all traffic devices, including signals. So you want to conduct traffic warrants or do the analysis before you make decisions about installing or removing signals or adding or taking away turning movements.”
Smith estimated that adding a left-turn arrow to the signal at Broadmoor and Martway would cost about $2,000. Ward 1 Councilman Pat Quinn asked whether the city would lose any federal funds if it were to install the protected left-turn signal at Broadmoor and Martway without first having a traffic study done. Berger and Smith both said no.
“Then why don’t we just do it?” Quinn asked.
Belger said that doing so without first having a traffic study conducted could raise legal problems.
“It does open you up to potential liability if somebody has a crash at that intersection and there’s a protected left turn, and is that warranted?” he said. “And we don’t have anything to back it up to say that it was.”
Smith said the main issue was more fundamental than whether the city should spend the money for a traffic study for the left-turn arrow addition at Broadmoor and Martway, or whether it should spend the money for a new traffic signal at Woodson and Johnson Drive.
“(The issue is) how are we going to make decisions related to traffic engineering in the community?” she said.