New interchanges being constructed on I-15 will get rid of some left-lane exits that have been the bane of motorists in Utah for up to 30 years.

During that time, motorists on westbound I-80 wanting to head south on I-15 had to weave across traffic to merge onto I-15 from I-80's left lane.When I-215 was constructed in the mid-1980s, southbound I-15 motorists exiting at 7200 South had to cross lanes of traffic coming from I-215.

Builders say the new I-15, with its collector-distribution roads now under construction, will eliminate that type of hazard. The collector roads will run parallel to I-15 and are designed to minimize the points where traffic merges.

Most of the collector-distributor work is being done at three locations: between the I-215 and I-15 interchange in Murray and 7200 South in Midvale, along the north side of I-80 between State Street and the I-15 interchange in South Salt Lake, and along I-15 north of that interchange to 1300 South.

The south-end interchange of I-15 and I-215 is getting collector-distributor roads for the first time.

Heading south on I-15, merges will be simplified when traffic exiting at 7200 South and moving from I-215 will come together on a collector road before joining I-15.

Heading north, I-15 motorists can merge onto a collector road with the choice of exiting at 7200 South or continuing north to go either east or west on I-215.

Meanwhile, the massive I-80 and I-15 complex near 2800 South will be expanded to include a direct connection to the 2100 South freeway (U-201). With that east-west state highway tying into the interchange, the 2100 South surface street will be moved north and kept separate from the freeway.

A north-side collector system along I-80 from the State Street interchange is designed to ease traffic flow on to I-15.

I-80 motorists wanting to go southbound formerly had to cross the faster lanes to get to a ramp in the left lane.

"The left-hand, one-lane exit ramp is eliminated and a new, wider right-hand exit ramp with two lanes and wide shoulders will take traffic south," said Dave Nazare, technical-support manager for the Utah Department of Transportation.

The connection between I-15 and west I-80 coming in from Salt Lake City International Airport also has been revamped.