State aims to widen Chinden between Meridian, Caldwell first to 4 lanes, then to 6

Plans are in the works to widen one of the Treasure Valley’s most heavily traveled roads between Meridian and Caldwell.

The Idaho Transportation Department proposes to make U.S. 20/26, Chinden Boulevard, a six-lane divided highway from Eagle Road west to Interstate 84 over the next quarter century.

To relieve worsening congestion and maintain safe driving conditions, ITD envisions widening the highway to a four-lane divided highway between 2021 and 2032 and to six lanes by 2040. Most of the 15-mile stretch is two- and three-lane rural highway.

In all, the work would cost an estimated $350 million.

The timing is an estimate, too. After the entire stretch is widened to four lanes, the department plans to make it six “when traffic volumes warrant it and when funding is available,” said spokesman Adam Rush. “It’s not known at this time when that will occur, or in which decade. The amount of growth and increase in traffic is a factor, along with future funding.”

Funding is already in place to start construction in 2021 to widen one mile between Eagle and Locust Grove roads to four lanes.

The department said the project might be expedited if more federal money becomes available under President Donald Trump’s call for increased infrastructure spending.

The plans include a new type of intersection aimed at improving traffic flow by reducing the amount of time vehicles spend on left turns and yellow signals.

They also include bike lanes and sidewalks in some areas. Most of the stretch lacks them now.

THE 3 PHASES

The long-term project is tentatively divided into three construction phases:

Near-term (through 2024): Widen six miles from Eagle Road west to McDermott Road to four lanes.

Mid-term (2025-2032): Widen 8 1/2 miles from McDermott west to Smeed Parkway to four lanes. Widen three miles from Eagle Road west to Linder Road to six.

Long-term (2033-2040): Widen 12 miles from Linder west to I-84 to six lanes.

NEW-STYLE INTERSECTIONS

The new intersections would be complex. They would require drivers turning left to:

1. Move into a left-turn lane that is farther back from the intersection than turns lanes are now.

2. Wait for a light to turn diagonally left across oncoming traffic well before the intersection.

3. Cross that traffic on the green.

4. Bend right and continue to a second light at the intersection itself as oncoming traffic continues to the driver’s right.

5. Turn left on the green at the intersection without a left-turn arrow, which would not be needed because the driver already crossed the oncoming traffic.

These “continuous flow intersections” were first developed in Mexico. They cost far less than overpasses, according to a report by COMPASS, the regional planning agency for Ada and Canyon counties. There are several on the Bangerter Highway in Salt Lake County, Utah.

Eventually, the Chinden Boulevard intersections with Locust Grove, Meridian, Linder, Star, Middleton and Eagle roads will be reconfigured to this type of intersection, Rush said.

FOR NOW: MINOR CHANGES

ITD also has some minor improvements slated for U.S. 20/26 from Eagle Road to the freeway within the next five years:

▪  2017: Pavement restoration from Middleton Road to Locust Grove Road.

▪  2019: Add right-turn lanes at the Midland Road, Northside Boulevard and Can-Ada Road intersections.

▪  2019: Widen the Franklin Boulevard intersection in Caldwell.

▪  2012: Replace a culvert at the Phyllis Canal Bridge.

HAVE YOUR SAY

The Idaho Transportation Department has drafted a 206-page study that includes a conceptual plan with recommended improvements and right-of-way needs. It also includes a draft environmental assessment showing how the improvements would affect noise, air quality, cultural and historic resources and other environmental factors.

The department’s next step is to hold public meetings on the corridor study and environmental assessment . It plans two in early March:

▪ Tuesday, March 7: 4 to 7 p.m., Ambrose School, 6100 N. Locust Grove Road, Meridian.

▪ Thursday, March 9: 4 to 7 p.m., Thomas Jefferson Charter School, 1209 Adam Smith Ave., Caldwell.

The meetings will have an open-house format with staffers available to answer questions and collect comments. These will be the only public meetings to comment on the study, ITD said.

ITD will accept public comment on the draft study through March 31. Comments can be emailed to adam.rush@itd.idaho.gov or mailed to Adam Rush, Idaho Transportation Department, 3311 W. State St., Boise, ID 83703.

This story was originally published February 24, 2017 at 10:16 PM with the headline "State aims to widen Chinden between Meridian, Caldwell first to 4 lanes, then to 6."