Morning commuters can expect additional delays of up to 20 minutes on northbound I-15 through Midvale beginning in late October.

That's when Wasatch Constructors, UDOT's I-15 reconstruction contractor, will shift all freeway traffic onto new concrete pavement - the first stretch of rebuilt freeway to open - between I-215 and 9000 South.In the new configuration, northbound traffic will be reduced from three lanes to two at about 6700 South. Currently, there are three northbound lanes until about 6000 South.

By now, Salt Lake Valley drivers are used to merging from three to two lanes on the freeway. Wasatch and Utah Department of Transportation officials don't expect that to be a problem.

The difficulty is that trucks headed for westbound I-215 also must go through the narrowed, two-lane zone before taking a temporary ramp to the western belt loop.

When the new, permanent connector to westbound I-215 opens early next year, trucks traveling north on I-15 will access that ramp near 7200 South and won't enter the restricted area at 6700 South. That, Wasatch and UDOT predict, will ease the congestion on northbound I-15.

In the meantime, Wasatch is asking employers to encourage more workers to carpool or take the bus. Northbound motorists are urged to take alternate routes or plan on their morning commutes taking up to 20 minutes longer.

"We hope people really will plan ahead so that they can get to where they need to go with as little frustration as possible," said Wasatch spokesman Brian Mauldwin.

"This is a prime example where if they don't plan ahead I would expect delays up to 20 minutes."

Wasatch also has warned truckers to plan on a "temporary bottleneck" until the westbound I-215 ramp opens.

Southbound I-15 also will be restricted to two lanes between I-215 and 6700 South in late October, but officials don't expect the same delays to occur during the commute evening.

For one thing, motorists won't have to merge because southbound I-15 is already restricted to two lanes north of I-215. The change will simply lengthen the two-lane zone. And motorists bound for I-215 will already have turned off southbound I-15 at that point.

Traffic must be limited to two lanes in each direction in that area because a new freeway bridge, which will eventually carry only southbound traffic above the railroad tracks at about 6500 South, is not wide enough to handle additional lanes.

To this point, Wasatch has maintained three lanes of traffic in each direction on I-15 through Midvale - from I-215 to 9000 South. The rest of the 17-mile corridor is reduced to two lanes in each direction.

By the end of the year, the contractor plans to switch traffic onto the new southbound side of the freeway from 9000 South to the end of the work zone at 10600 South, increasing traffic flow there from two lanes in each direction to three.

At the same time the late-October traffic switch occurs, two new ramps will open - the new connection from eastbound I-215 to southbound I-15 and the ramp from northbound I-15 to eastbound I-215.