Some morning classes will start five minutes earlier. Shuttles to Science Hill will be diverted. And the renovation of the Prospect Street bridge has been delayed.

Again.

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[ydn-legacy-photo-inline id=”6544″ ]

For the second year in a row, construction on the short span across the Farmington Canal, a bike trail from New Haven harbor to Northampton, Mass., and the surrounding area will push 9:25 a.m. classes five minutes earlier and force Yale Transit to reroute its shuttles. Although city engineers plan to open one lane of the bridge Monday to ensure access to the new Yale Health building at 55 Lock St., authorities say minor projects surrounding the bridge, which itself was once slated to be finished in December, could delay its full reopening until as late as June 2011.

Trying to get all the projects in line has “been like herding cats,” said assistant city engineer Larry Smith.

Prospect Street has been open to cyclists and pedestrians through a narrow lane between the construction since January. A second lane will open sometime this fall, Smith said, but there are too many variables involved to predict when the bridge will reopen completely.

“The project is substantially complete at this point,” said Tim Young, the project manager for Anchor Engineering Services, the contractor in charge of construction. “The ongoing adjacent projects are somewhat controlling the schedule.”

But there are at least three adjacent projects, among them a $4.5 million pipe replacement project that could last another four weeks, said Mario Ricozzi, chair of the city’s Solid Waste Management Commission.

In the meantime, the University’s transit administrators have rerouted the blue, orange and red lines around Prospect Street for a second year. The blue and orange lines will take the same routes as last year (up Hillhouse and Whitney avenues, respectively), but the red line will now include a stop at the Yale Health building, said Donald Relihan, who oversees Yale transit.

Even if parts of the bridge open this fall, Relihan said, the University will not reroute the shuttle until the bridge is completely open.

“Of course, last year we thought it’d be completely open,” Relihan said, “but we have to deal with what’s in front of us now.”

With student trips back from Science Hill delayed, the Yale College Dean’s Office decided to move classes that usually start at 9:25 a.m. to 9:20 a.m. for the second year in a row, Yale College Registrar Jill Carlton said Thursday.

Science majors said the continued disruption of shuttle service on Prospect Street would be inconvenient, especially in rough weather.

“The bus takes significantly longer, so if you’re running late for classes, there’s no way to save yourself,” said Ari Livne ’12, who is considering the biomedical engineering major. “If you want to take the bus, you have to be way, way ahead of time to get there on time. Otherwise,” he said, “you have to make the trek.”

Things looked better a year ago. In September 2009, the project’s managers anticipated that the bridge might open last December, six months ahead of schedule, which was especially welcome since the multi-million-dollar makeovers of the nearby Hillhouse Avenue and Temple Street bridges were notoriously delayed.

But in the end, the Prospect Street bridge would share their fate. Delays in utilities projects caused Yale to keep its original opening date. And when construction neared completion in June, a subcontracted worker installing a nearby gas main accidentally sawed through a concrete slab underpinning the structure. City engineers must finish repairing the damage, Smith said.

Among the other roadblocks to completing the renovation are electricity, gas and sewage work. And Smith said workers must lay asphalt but might not until after the winter because they must wait until the utilities projects are completed, and asphalt cannot dry in winter temperatures. As of now, he said, he does not believe workers are on track to complete their projects before winter.

Kenneth Kemp, a supervisor for the Water Pollution Control Authority, which is completing the pipe replacement project, said Thursday that the sewage work was about 40 percent complete. Tassie said contractors are also painting traffic lines and installing traffic lights on the bridge to prepare for its reopening.

“You can see there are a lot of variables, and you have to have the perfect storm for everything to come together,” Smith said.