Depending on the time of day, the stretch of Mount Rose Avenue from Interstate 83 to Route 24 can be a nail-biter for motorists.

Work is under way for a major interchange redesign project at Exit 18, expected to ease congestion, but it will be about three years before the area is construction-free.

Barrels line Mount Rose Avenue past Greenspring Plaza, blocking finished from unfinished areas between Hartford Road and Greenspring Road.

PennDOT spokesman Greg Penny said the road is being widened from three lanes -- two eastbound and one westbound -- to four lanes, with two in each direction.

A $1.9 million contract, the work began last April and is scheduled for completion in early July. Penny said paving can't start until April; asphalt companies close for the winter because blacktop is a temperature-sensitive material.

Next phase: The next phase of the project includes reconstructing and widening Mount Rose Avenue to five lanes from Hartford Road to just past Chambers Road,

Penny said. There are currently three lanes, one in each direction and a center turning lane. One lane will be added in each direction, and the light at Chambers Road will be removed.

That project, costing $3.2 million, is expected to start this April and finish by mid-May 2015, Penny said.

In July, PennDOT will go to bid on the next portion of the project, widening Route 24 between Carol Road and Windsor Road and widening the Route 24 intersection with Route 124 and providing turning lanes.

Work is expected to start in late summer or early fall of this year, finishing in the summer of 2015.

Big finale: The $56.2 million interchange redesign project includes:

---a loop ramp for eastbound traffic on Mount Rose from I-83 southbound,

---aligning the northbound off-ramp with Haines Road so drivers won't have to cross two lanes of traffic on Mount Rose to get into the left-turn lane, and

---adding a new ramp so drivers headed east on Mount Rose can enter I-83 northbound without having to make a left turn.

Penny said the project is likely to take three construction seasons to complete, with bids being opened in January 2015.

Under the current schedule, it should be finished at the end of 2017, he said.

-- Reach Christina Kauffman at ckauffman@yorkdispatch.com.