WESTMINSTER — Several north metro cities together are pitching in nearly $5 million toward a $44 million project to relieve crippling congestion in a 6-mile stretch of Interstate 25 between U.S. 36 and 120th Avenue.

If the proposal is approved by federal highway officials, one new managed toll lane in each direction would be built on I-25, said the Colorado Department of Transportation.

"We could alleviate all that congestion and get it done in a couple of years," said Adams County transportation coordinator Jeanne Shreve.

More than 175,000 vehicles and 4,300 bus riders travel that stretch of I-25 each day, where peak traffic jams the span for four hours both morning and night, and vehicles often crawl at 15 mph instead of the posted 55 mph, CDOT said.

The project would extend current I-25 managed lanes from U.S. 36 to 120th by using existing pavement and narrowing the inside shoulder. Carpools and van pools, along with buses, would have access to the managed lanes free of charge. Solo drivers would pay a toll to use them.

Planners say the managed lanes would shave up to 8 minutes from the commute for transit riders entering I-25 from the Wagon Road park-n-Ride in Westminster. There also would be $282,000 in savings for RTD each year because the express buses would be more efficiently used, according to an RTD analysis.

For car travelers in the toll lanes, the commute from Adams County could be cut by 20 minutes, CDOT said.

Northglenn chipped in $550,000 in matching funds to help nab the Transportation Investment Generating Economic Recovery (TIGER) grant.

Northglenn Mayor Joyce Downing said the investment will aid residents who commute to work. I-25 "runs through our community, is one of the region's major thoroughfares and a critical transportation route for residents participating in the regional economy."

Adams County is putting down $1.5 million, Thornton $1.75 million, Westminster $500,000, Federal Heights $150,000, Broomfield $50,000, Weld County $25,000 and the Regional Transportation District $750,000.

CDOT is a contributing $15.5 million, while the Denver Regional Council of Governments is pitching in $5 million. A $3.5 million CDOT FASTER transit grant has been secured.

CDOT officials expect to submit a $15 million federal grant application on Monday.

The state applied for the same grant late last year but lost, due in part to heavy competition. There were 848 applications submitted to the U.S. Department of Transportation in 2011, and 46 were chosen, said Lizzy Kemp, CDOT Region 6 planning and environmental manager.

So far this year, CDOT recruited as many cities and town as possible for matching funds. "They (federal highway officials) really wanted to see that everyone had a financial stake in this project," Kemp said.

The north metro I-25 proposal is up against highway projects in Pueblo and Colorado Springs.

But if north I-25 is picked, there will be other benefits besides smoother commuting in the north metro area. More than 450 jobs will be added, and existing sound walls would be repaired and others built.

"This is a top priority of CDOT, and a lot of good will come from it," Adams County's Shreve said.

Monte Whaley: 720-929-0907 or mwhaley@denverpost.com