The Idaho Springs business route from Interstate 70 lines Colorado Boulevard (old U.S. 6-40) through the linear city. Designated as Route 070K by the Colorado Department of Transportation, the 2.711 mile route originates at a wye interchange (Exit 239) from I-70 just outside the western city limits. Passing just north of the city center, Business Loop I-70 intersects the north end of SH 103.

The east end of Colorado Boulevard was rebuilt from a tight parclo interchange between April and fall of 2015. Work involved replacing the Colorado Boulevard Bridge over I-70 and realigning the boulevard slightly east. A roundabout was also added where the north side ramps come together, while separate ramps along I-70 east for Colorado Boulevard were consolidated. The new overpass accommodated the I-70 Mountain Express Lanes project.1

Planned Construction at the east end will improve the south side I-70 Frontage Road to provide connectivity with the 2012 rebuilt section linking with the Hidden Valley / Central City interchange (Exit 243). The gravel section of CR 314 will be replaced with a paved road during the project.

Home to around 1,700, Idaho Springs is perhaps best known for its mineral baths, which give the city its name. One of the more interesting side trips from Idaho Springs is the "Oh My God" Road, which connects Idaho Springs with Central City and Blackhawk (SH 119 in Gilpin County) via Clear Creek County 279 and Gilpin County 279.

Notable sign changes in 2016 include greenouts on Interstate 70 guide signs for the Idaho Springs exits. The green outs cover Business Loop I-70 shields. Additionally, shields for both the business route and SH 103 were not posted along Colorado Boulevard in Idaho Springs, and no signs were noted for the route between 20th Avenue and the roundabout at Exit 241 from the west. Route 070K is still inventoried by CDOT as of April 2017.

Business Loop I-70 east
Business Loop I-70 eastbound overtakes Stanley Road east from Exit 239 to Colorado Boulevard to enter the Idaho Springs city limits. 08/11/16
The initial stretch through Idaho Springs consist of residential blocks north and south of Colorado Boulevard. This scene looks at 6th Avenue. 08/11/16
A trailblazer directs truck traffic headed to I-70 east to remain along Colorado Boulevard in lieu of forthcoming SH 103 south on 13th Avenue. 08/11/16
This shield and guide sign for Colorado 103 south on Business Loop I-70 east was removed by 2016. Colorado 103 starts a 22.5 mile route south to Echo Lake and Squaw Pass here. 08/29/04
Miner Street east merges with Business Loop I-70 (Colorado Boulevard) by a shopping center. 08/11/16
2 photos
2 photos
Business Loop I-70 east expands into a commercial boulevard from Miner Street to I-70. 08/11/16
3 photos
3 photos
3 photos
Traffic separates at a roundabout for the westbound on-ramp back toward Empire and the continuation of Colorado Boulevard across I-70. 08/11/16
Spanning Interstate 70 on a 2015-built overpass, Colorado Boulevard meets County Road 314, the south side frontage road, and the eastbound on-ramp for Denver. 08/11/16
Ramp meters operate during peak travel periods for inbound Interstate 70. 08/11/16
Business Loop I-70 west
Construction of the new overpass for Colorado Boulevard above I-70 included the addition of a roundabout with the north side ramps from Interstate 70. 08/11/16
The westbound off-ramp (Exit 240) ties into the roundabout opposite the on-ramp to Grand Junction. 08/11/16
A guide sign references just Colorado Boulevard, with the Business Loop unsigned from this point west through Idaho Springs. 08/11/16
A number of motels, restaurants and gas stations line Colorado Boulevard west to the split with Miner Street. 08/11/16
Miner Street parallels Colorado Boulevard one block to the south to the Idaho Springs city center. 08/11/16
Older traffic lights in operation along Colorado Boulevard at the Idaho Springs Fire Department, east of 20th Avenue. 08/11/16
Reassurance marker for Business Loop I-70 west at Colorado Boulevard and 17th Avenue. This assembly may have been removed during construction in 2016. 02/02/02
Confirming marker for Business Loop I-70 west formerly posted after the intersection with SH 103 (13th Avenue) south. This assembly was removed by 2016. 08/29/04
Colorado Boulevard westbound at 7th Avenue. The actual springs that give Idaho Springs its name are located south of this point. 08/11/16
Stanley Road branches southwest from Colorado Boulevard ahead of the Business Loop I-70 transition onto Interstate 70 west. Stanley Road parallels the freeway west to Downieville as old U.S. 6-40. 08/11/16

  1. "Exit 241 Reconfiguration." Colorado Department of Transportation, project web page. Accessed April 10, 2017.

Photo Credits:

02/02/02, 08/29/04, 08/11/16 by AARoads

Connect with:
Interstate 70
State Highway 103

Page Updated 04-10-2017.

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