Once Route 23 is closed between Balligomingo and Swedeland Road early in May, vehicles will be detoured three miles for a trip that will take about 20 minutes, twice the usual time, officials warned.
"Once you close that road and increase the traffic on the detour roads, your travel time is going to double," said Eugene Blaum, spokesman for the Pennsylvania Department of Transportation.
The $5.4 million project will fix sight problems at the intersection, which is angled in a way that makes it difficult for drivers to safely merge onto Route 23 from Balligomingo.
From 2005 to 2009, officials logged six nonfatal crashes there, said Larry Bucci, PennDot traffic safety engineer.
Leo D. Bagley, assistant director of the Montgomery County Planning Commission, sees the need to improve Balligomingo, which acts as the back way to West Conshohocken from the Schuylkill Expressway's Gulph Mills exit.
"This will improve traffic options for drivers into this part of Upper Merion and West Conshohocken," Bagley said.
The new design shifts Balligomingo 400 feet to the west so it hits Route 23 at a more T-shaped angle, and raises the intersection five feet. There will be a traffic light instead of a stop sign, and dedicated turn lanes where no turns are now allowed.
In the first year of the project, Route 23 will be blocked off and detoured at Balligomingo, for utility and bridge rebuilding, PennDot said. Work began Thursday to install temporary traffic signals at Trinity and Balligomingo Roads, plus Trinity and Holstein Roads, in Upper Merion.
In stage two, Route 23 will be closed between Matsonford and Swedeland Roads. Balligomingo will be closed and detoured between Route 23 and Trinity Road for all of July 2012, as work crews redo the current juncture of Balligomingo and Route 23.
In stage three, Route 23 will be reopened while Balligomingo remains closed, to complete road and utility construction. Stage three will run from summer 2012 through May 2013, officials said.
During the closures, locals will be allowed access "up to the construction zone," Blaum said. Others will be detoured west on I-76 to the Gulph Mills exit, then east on Trinity, Holstein, and Swedeland to rejoin Route 23.
Reaction to the closures is mixed. "Good grief," said James R. Matthews, chairman of the county commissioners, when told of the closures. But on second thought, he said the improvements were needed.
David Fiorenza, West Conshohocken's interim manager, said he had too little time on the job to comment, but Upper Merion Township spokesman Edward Higgins called the plan "a trade-off."
"If this is going to get done, and it needs to be, they are going to have to close the roads," Higgins said. "We have concerns, but they are around what the detours are going to be, and in fact if the traffic follows those detours, and if they are well-marked."
GlaxoSmithKline, whose Upper Merion plant is at Route 23 and Swedeland Road, has pointed employees toward flexible work options, telecommuting, or adjusting their hours, said spokeswoman Jennifer Armstrong.
SEPTA's Route 95 bus will operate via the Schuylkill Expressway for direct service to and from Conshohocken, Metroplex Shopping Center, and Plymouth Meeting Mall; buses will be specially marked, spokesman Andrew Busch said.
One bright spot is that PennDot plans to reopen Conshohocken Road on the east side of the Schuylkill before it closes Route 23 on the west side, Blaum said. Conshohocken Road has been closed from Fayette Street to Ridge Pike in Plymouth Township since May 4, 2009, for replacement of two bridges.
All that may be lost on the Front Street residents whose lives were disrupted during a project to do curb cuts and widen the street east of Bullock Avenue. That project ended last year but is still fresh in residents' minds.
Rachel Nolan-Trefz, 38, is one of them. Once Route 23 is closed in May, she foresees problems reaching King of Prussia, Bridgeport, and other points west.
"It's bad enough that Conshohocken Road is closed off," she said. "We've got to go all around the world to get to Bridgeport?"
Contact staff writer Bonnie L. Cook at 610-313-8232 or bcook@phillynews.com.