It's the merge with which too many Boulder motorists are painfully familiar.
Westbound drivers on Arapahoe Avenue cross Folsom Street and suddenly find themselves shoved into a single lane of traffic, where they rumble over cracking asphalt and tilt slightly on an uneven roadway as they make their way toward Broadway.
While the narrowing of Arapahoe isn't going to change any time soon, the city of Boulder is ready to pour $5 million into making major improvements in the seven-block stretch between Folsom and 17th streets.
The 18-month effort, which starts at the end of May, will transform aging asphalt into smooth concrete, widen sidewalks on each side of Arapahoe by a foot or two, reduce pooling and standing water with new curbs and storm sewers, and add new landscaping in the corridor. New wheelchair-friendly curb ramps, an extension of the student dropoff area and multi-use path on the south side of the road near Boulder High School, and improvements to bus stops are also in the plans.
City staff members presented details of the reconstruction project at an open house Monday evening at the West Senior Center.
"There are a lot of folks traveling through here, whether by car, by bus or by bicycle," said Noreen Walsh, a transportation planner for Boulder. "In the long run, we'll have a much better roadway and transportation corridor for all."
But until the work is done -- sometime around October 2014 -- there will be plenty of headaches to go around for motorists, residents of the Goss Grove neighborhood and business owners along Arapahoe Avenue.
For a 12-week period this summer, and again next summer, the road will be open only to eastbound traffic while westbound vehicles are detoured north to Canyon Boulevard. That means westbound motorists trying to reach Naropa University or businesses in that stretch of Arapahoe will have to double back on 17th Street to get to their destination.
At least one sidewalk down Arapahoe Avenue will remain open at all times, project officials said.
Walsh said the city is strategically scheduling the worst detours for the summer months -- between mid-May and mid-August -- when the student populations dwindle. From September to May 2014, Arapahoe will accommodate two-way traffic but will lose its center turn lane.
"We are really trying to respond to decreased traffic volumes in the summer," Walsh said.
An average of 22,000 vehicles travel between Folsom and 17th streets every day.
Bob Murphy, manager of ListenUp, said there's no doubt his business will be hit hard by the project.
"When you deflect traffic, it's not going to help business," he said at the open house Monday. "But it's long overdue. The drainage is terrible, the potholes are terrible."
Murphy said he's watched the road outside ListenUp degrade over the years, with the city periodically repaving sections. He said he is glad to see a major infrastructure upgrade on tap this time.
Project manager Bryant Gonsalves, of Boulder's transportation department, said the last significant overhaul of that section of Arapahoe Avenue was 15 years ago. The city chose to go with concrete as a road surface this time because it lasts significantly longer than asphalt and prices for the material are more in line these days with asphalt.
The city is paying for the project out of the $49 million capital improvement bond issue passed by voters in 2011. Gonsalves said it's possible that the improvements could be extended to 15th Street, if additional funding is found and a contractor submits an aggressive bid.
Randy Leever, who has owned Boulder Stained Glass Studios at 1920 Arapahoe Ave. for 37 years, said he worries about increased collisions between cyclists and pedestrians on the sidewalks as a result of the project. There are no bike lanes on Arapahoe west of Folsom Street and no room to add any, according to the city.
With sidewalks widened to 6 feet, Leever said that will only encourage cyclists to pedal harder and throw a few extra miles per hour on their speedometers.
"I'm afraid with the wider sidewalk, they'll just go that much faster," he said. "There's no mitigation of the bicycle-pedestrian conflict."
As for customers reaching his business during the project, Leever said he'll lose impulse shoppers but not the loyal customers who know where he is. Ultimately, he said, it's all for the better.
"The street needs to be done," he said.