Local authorities may request route assignment from the Caltrans Transportation System Information Program, and all requests require approval of the executive committee of the American Association of State Highway and Transportation Officials (AASHTO).

At that time, AASHTO assigned the I-305 designation to the west half, which met Interstate Highway standards.

At the intersection of Front Street and 6th Street, which is the northern terminus of Wyoming Highway 150 (WYO 150) and the southern terminus of WYO 89, the business route turns north and crosses the Union Pacific Railroad's Evanston Subdivision rail line.

I-80 BL intersects WYO 414 in the hamlet of Urie then curves north onto the town of Lyman.

Next to the railyard, the business route has an intersection with WYO 530 (Uinta Drive), which heads north, then curves back south and bridges the business route and the railyard on its way to the portion of the city south of the Green River.

Immediately east of WYO 530, I-80 BL rejoins the mainline Interstate at exit 91, another trumpet interchange.

Downtown is served by WYO 430, which I-80 BL intersects just east of a rail line that branches north from the Union Pacific Railroad's Rawlins Subdivision.

I-80 BL begins at I-80 exit 211 on the western edge of the city and heads east concurrently with WYO 789 along Spruce Street.

is a business loop of I-80 that spans 6.357 miles (10.231 km) through Laramie in southern Albany County.

In downtown Laramie, I-80 BL and US 30 turn east onto Grand Avenue, which runs along the southern edge of the University of Wyoming campus.

The highway curves southeast and leaves the city of Laramie just north of its end at the trumpet interchange of I-80 exit 316.

is a business loop of I-80 that runs 6.935 miles (11.161 km) through Cheyenne in central Laramie County.

I-80 BL begins at I-80 exit 358, a three-ramp partial cloverleaf interchange next to the Union Pacific Railroad's Laramie Subdivision rail line at the western city limits of Cheyenne.

I-80 BL and US 30 leave downtown Cheyenne and the vicinity of the railroad as they pass Holiday Park.

The business route and state highway cross over Union Pacific Railroad's Sidney Subdivision on the way to the eastern terminus of I-80 BL at I-80 exit 364 across from the Laramie County Fairgrounds.

Concurrent highway routing in the Pine Bluffs area is along US 30 (including Parsons Street).

All signs and references to the business loop in Nebraska were completely removed in 2009, due to a decommissioning of all such related Interstate routes statewide.

It served as a loop through Sidney, near I-80 and traversed approximately nine miles (14 km) over multiple highways.

All signs and references to the business loop were removed in 2009 due to a decommissioning of all such related Interstate routes statewide.