Colorado Highways:
Interstate Business Loops and Spurs

Here, you can view information about the sundry Interstate business loops (BLs) and business spurs (BSs) in Colorado. CDOT has made quite extensive use of them. Basically, there are two flavors of business routes from Interstate Highways:

Colored Table Format

White

Currently active, Marked on the mainline

Tan

Currently active, Unmarked on the mainline

Blue

Defunct

BS25
Aguilar

Length*: 1.94mi
NE End: Jct I-25 Exit 34 northeast of Aguilar
SW End: Main St./Fir St. in Aguilar

Average Annual Daily Traffic (2008): 670

Guide:
This one goes from a diamond interchange at I-25 southwest to Aguilar. The historic alignment of US 85-87 is west of I-25 at this point, going right through Aguilar.

I-25 main listing

BL25
Walsenburg

Length*: 4.04mi
S End: Jct I-25 Exit 49 south of Walsenburg
N End: Jct I-25 Exit 52 north of Walsenburg
US Highway Replaced: US 85-87

Roadway Names: Main Street & Walsen Avenue

NHS: While concurrent with US 160 from 7th to 5th Sts.

Milepost Guide:

  • 0.00: I-25 Exit 49 interchange (begin BL 25)
  • 1.36: South jct US 160/7th St.
  • 1.51: North jct US 160/5th St.
  • 3.64: SH 69
  • 4.04: I-25 Exit 52 interchange (end BL 25)

Average Annual Daily Traffic (2008):

  • 2100 at I-25 south
  • 4600 south of US 160/7th St.
  • 9600 north of US 160/5th St.
  • 5300 at I-25 north

Guide:
From Exit 49, BL 25 goes northwest through Walsenburg, right along the old alignment of US 85-87. Through town, it uses Main Street which switches to Walsen Ave north of 1st. Then, north of town it curves back northeast, and again hits I-25 at Exit 52.

At 7th Street BL 25 meets US 160 where one turns to head west to La Veta and Alamosa. CDOT defines US 160 as going north along BL 25 for two blocks to 5th St, then US 160 turns east and goes out to I-25 Exit 50. However, signs in the field do not agree with that and generally mark US 160 as going south along BL 25 to Exit 49.

Photo Gallery:

BL25
Colorado Springs

Length*: 6.75mi
S End: Jct I-25/US 85 Exit 140 in south Colorado Springs
N End: Jct I-25 Exit 148 in north Colorado Springs
US Highway Replaced: US 85-87

Roadway Names: Nevada Avenue

History:
This business loop was along the historic alignment of US 85-87 through Colorado Springs, Nevada Avenue. It started at Exit 140 then headed due north right through central Colorado Springs, returning to I-25 at Exit 148.

BL 25/Nevada Ave was turned back to the city on October 1, 2007, although it took several months for signage to change. It was turned back as part of the massive swap to get Powers Blvd to become SH 21.

Photo Gallery:

  • South End BL 25 Overhead Signs. A neat-o picture of a vintage sign at the south end of BL 25 in Colorado Springs. This is southbound Nevada Ave. approaching the I-25 overpass at Exit 140. The letters and US shields are all button-copy, and the Colorado shield is the pre-1967 design with "COLO" at the top. This sign has disappeared as Exit 140 is reconstructed. Here's a close-up, taken by Russell Kroll in June 2001. (February 2001)
  • BL 25/US 24 Oops. Southbound on Nevada Avenue at Cimmaron Street. One problem: This isn't US 24 anymore! Photo courtesy Russell Kroll. (June 2001)
  • Parkway Median. Extra-wide landscaped median for a parkway effect. Northbound Nevada at Saint Vrain Street. (September 2003)
  • Alternate Route Lights. Covered lights and signs on a signal pole on northbound Nevada at Austin Bluffs. Supposedly, if they were uncovered, they would light up when the alternate route is activated. Russell Kroll writes: "Here's an 'alternate route' display. These have appeared all over town, but none of them appear to be exposed. I assume this will be used to route traffic up and down Nevada when something really bad happens on I-25. TxDOT does something similar with signs along Fredericksburg Rd. for I-10 here in San Antonio. I've never seen them lit, but they supposedly can be used to keep traffic away from the freeway in a pinch." Photo by Russell Kroll. (May 2003)


25
Castle Rock

Length: 1.2mi
S End: Jct I-25 Exit 181 in south Castle Rock
N End: Jct I-25 Exit 182 in north Castle Rock
US Highway Replaced: US 85-87

Roadway Names: Wilcox Street

History:
This loop used Wilcox St. going north through town. It started at Exit 181, the Plum Creek Parkway exit, then went north right through downtown on Wilcox, returning to I-25 at Wilcox/Wolfensberger Road diamond interchange at Exit 182. It existed most likely up through the early 1990s, and was definitely turned back by 1996.

Interesting side note: SH 86 ended at BL 25 at 5th and Wilcox downtown. After the BL 25 turn back, SH 86 had its end dangling at nothing.

BL70
Grand Junction

Length*: 13.27mi
W End: Jct I-70/US 6 Exit 26 northwest of Grand Junction
E End: Jct I-70 Exit 37 northeast of Clifton
Places: Grand Junction, Fruitvale, Clifton

Expressway:

  • From I-70 Exit 26 southeast to central Grand Junction. Includes interchanges at US 6 (North Ave) and Redlands Pkwy.
  • From central Grand Junction northeast to I-70 Exit 37.

NHS: Entire length.

Milepost Guide:

  • 0.00: I-70/US 6 Exit 26 interchange (begin BL 70)
  • 4.36: West jct US 6/North Avenue interchange
  • 4.95: SH 340
  • 5.66: US 50/5th Street
  • 9.30: East jct US 6/North Avenue
  • 11.71: SH 141
  • 12.17: US 6 west of Clifton
  • 13.27: I-70 Exit 37 interchange (end BL 70)

Average Annual Daily Traffic (2008):

  • 27,900 at I-70 west
  • 37,500 on BL 70/US 6-50 northwest of US 6/North Ave.
  • 32,700 on BL 70/US 50 southeast of SH 340
  • On BL 70/US 50 west of US 50/5th St. (two one-way streets): 18,300 eastbound; 16,700 westbound
  • 17,700 east of CR 29
  • 31,000 northeast of US 6/North Ave.
  • 27,500 northeast of SH 141
  • 18,900 at I-70 east

Guide:
BL 70 starts at Exit 26, where US 6 also crosses over from the north to the south side of I-70 heading east, and US 50 exits and heads southeast concurrent with US 6. US 6-50/BL 70 heads southeast toward downtown, while I-70 has a bypass which heads east. The three routes head southeast as an expressway, which includes an interchange at Redlands Parkway. At North Ave., there is another partial interchange, and US 6 heads east along North Ave. while BL 70/US 50 continue southeast. At North 1st St., it heads south, then curves east at downtown. Traffic splits onto two one-way streets, with eastbound traffic on Pitkin Avenue while westbound has Ute Avenue. At 5th St., US 50 turns south on its way to Delta.

BL 70 continues east, and the two directions join up at 10th St., each again on Pitkin Ave. BL 70 then curves northeast, becomes an expressway and again hits US 6 at North Ave. The two continue northeast to Clifton, where US 6 breaks off again and heads east to Mount Lincoln and Palisade. BL 70 continues northeast and hits I-70 at Exit 37.

Photo Gallery:

  • 24.5 Road. Westbound BL 70/US 50 approaching 24.5 Road in west Grand Junction's commerical strip. (September 2011)
  • BL 70/US 50 Approaching SH 340. Blurry picture of overhead signs on westbound BL 70/US 50 in west Grand Junction as it comes up to the SH 340 intersection. There's a somewhat ackward curve to the left as you go through the intersection, which CDOT notes with the sign. (September 2011)
  • US 50 Intersection. Overhead signs on eastbound BL 70/US 50 at the Pitkin/5th intersection downtown. The intersection features a double right turn. (July 2005)
  • BL 70/6/141 Markers. Eastbound BL 70/US 6 at the SH 141 intersection near Clifton. Oops! Those arrows are in the wrong place. (July 2005)
History:
Colorado's first diverging diamond interchange (DDI) opend at BL 70's west end at I-70 Exit 26 on February 27, 2014.

I-70 main listing



BL70
Palisade

Length: N/A
W End: N/A
E End: Jct I-70/US 6 Exit 44 east of Palisade
US Highway Concurrent With: US 6

Annual Average Daily Traffic (2004): 1200 on US 6 at I-70 Exit 44

Notes:
This business loop appears at only one location, on the westbound exit signs to US 6 at Exit 44, Palisade. Once off I-70, the business loop is not mentioned ever again, instead the road is signed only as US 6. If one wanted to return to I-70 after going west through Palisade, one uses Elberta Avenue, the connector street between US 6 and Exit 42, the west Palisade interchange.

BL70
Rifle

Length: 3.3mi
W End: Jct I-70/US 6 Exit 87 west of Rifle
E End: Jct I-70/SH 13 Exit 90 south of Rifle
US Highway Concurrent With: US 6

History:
This buisness loop may or may not have existed in the past. If it did, it probably would have used US 6 from Exit 87 east along I-70's north side, and then into Rifle. In the middle of town, it probably would have turned south on SH 13 back to I-70 Exit 90.

BS70
Silt

Length*: 0.22mi
S End: South frontage road at I-70 Exit 97 south of Silt
N End: Jct US 6 at Main St./9th St. in Silt

Average Annual Daily Traffic (2008): 7900



BS70
Eagle

Length*: 0.35mi
N End: Jct I-70 Exit 147 north of Eagle
S End: Jct US 6 in Eagle

Average Annual Daily Traffic (2008): 14,100

Photo Gallery:

  • Roundabout Signage. On southbound BS 70 at the approach to the roundabout at US 6 in Eagle. (June 2002)
  • Eagle Roundabout. A picture looking west on US 6 at the BL 70 roundabout on the east side of Eagle. Photo by Phil Demosthenes.



BS70
Edwards

Length*: 0.58mi
N End: Jct I-70 Exit 163 north of Edwards
S End: Jct US 6 in Edwards

Average Annual Daily Traffic (2008): 17,200

BS70
Avon

Length*: 0.43mi
N End: Jct I-70 Exit 167 north of Avon
S End: Jct US 6 in Avon

History:
Existed up until 1999, when it was turned back. While it did exist, it was not marked on I-70.

Photo Gallery:

  • South I-70 Roundabout. A roundabout on the south side of the I-70/BS 70 interchange in Avon. The roundabout is modified from the normal form to make it a "teardrop" roundabout, as Phil Demosthenes calls it. A driver isn't allowed to go all the way around, only part way, since if this were a traditional diamond interchange, drivers can't make left turns in that direction. Photo courtesy Phil Demosthenes.
  • I-70/Avon Road Roundabouts Overview. A shot looking southeast from above Avon providing a good overview of the Avon Road roundabouts. As Avon Road goes toward the upper right you can see it has additional roundabouts as it goes through Avon. Photo by Phil Demosthenes. (July 2004)



BL70
Frisco

Length: ?
Ends: ?

Guide/History:
Here's a quote from 1976 CDH route log: "SH 70 (Sec. J): Business loop through Frisco." That's all I know. Whether it was actually ever signed is unknown. What the exits were from I-70 probably would have been from Exit 201 east into Frisco, and then north via SH 9 back out to I-70 at Exit 203.

BL70
Idaho Springs

Length*: 2.71mi
W End: Jct I-70 Exit 239 in west Idaho Springs
E End: Jct I-70 Exit 241 in east Idaho Springs
US Highway Replaced: US 6-40

Roadway Names: Colorado Avenue

Milepost Guide:

  • 0.00: I-70 Exit 239 interchange (begin BL 70)
  • 0.95: SH 103/13th St.
  • 2.71: I-70 Exit 241 interchange (end BL 70)

Average Annual Daily Traffic (2008):

  • 2000 at I-70 west
  • 3900 east of SH 103
  • 7900 at I-70 east

Guide:
When I-70 was built through Clear Creek Canyon, it passed to the south of Idaho Springs (barely) and BL 70 was put along old US 6-40 through town. According to Robert Halonen there is still a "6-40 Hotel" in town. BL 70 starts at a partial interchange at Exit 239, and parallels I-70's north side about three blocks to the north. It follows Colorado Blvd. all the way east through town, then ends at another partial interchange at Exit 241.

History:
The Idaho Springs freeway bypass was actually built as part of US 6-40, not I-70, in 1960.



BL70
Golden
Lakewood
Denver
Aurora

Length*: 27.47mi
W End: Jct I-70/US 40 Exit 259 south of Golden
E End: Jct I-70/US 40-287 Exit 288 east of Aurora
US Highway Concurrent With: US 40

NHS: From Broadway in downtown Denver east to I-70.

Expressway:

  • From Golden east into Lakewood.
  • Four-lane divided from the Chambers Road area in east Aurora to I-70 Exit 288.

Roadway Names: Colfax Avenue

Average Annual Daily Traffic (2008):

  • 11,600 at I-70 Exit 259, Golden
  • 26,000 east of I-70 Exit 262
  • 26,900 east of Simms St., Lakewood
  • 26,600 east of SH 121/Wadsworth Blvd.
  • 32,600 east of SH 95/Sheridan Blvd., Denver
  • 35,200 east of US 287/SH 88/Federal Blvd.
  • 49,000 east of I-25
  • 42,900 east of Speer Blvd.
  • 27,900 east of Lincoln St.
  • 26,500 east of SH 2/Colorado Blvd.
  • 29,500 east of Dayton St., Aurora
  • 43,400 west of I-225
  • 26,000 east of Chambers Rd.
  • 5400 east of Tower Rd.

    Guide:
    BL 70 in metro Denver is concurrent with US 40 for its entire length. However, in the places that I have seen trailblazers it is the route that gets top billing. Signs usually have BL 70 on the top, US 40 in the middle, and (east of Federal) US 287 on the bottom.

    BL 70 starts at Exit 259, a diamond interchange at the mouth of Mount Vernon Canyon south of Golden. It then loops up to the north, then to the east, going through I-70 Exit 262. It then heads due east through metro Denver, using Colfax Ave. Along the way, it passes through Lakewood, and crosses into Denver at Sheridan Blvd. At Federal Blvd., there is a partial cloverleaf interchange and BL 70/US 40 is joined by US 287 heading east. Colfax then goes through I-25 Exit 210 and through downtown. It passes just adjacent to the City/County Building and the State Capitol. At Yosemite St. it crosses over into Aurora, but continues due east on Colfax Ave. It passes through I-225 Exit 10, then east of Aurora finally ends at I-70 Exit 288.

    Photo Gallery:



    BS70
    Watkins

    Length*: 0.40mi
    S End: South frontage road at I-70 Exit 295 south of Watkins
    N End: Jct SH 36 in Watkins

    Roadway Names: Watkins Road, or Watkins Mile Road.

    Average Annual Daily Traffic (2008): 4100

    Notes:
    This is the only marked BS on I-70 that I am aware of. Thanks to Robert Halonen for telling me about it.

    BS70
    Strasburg

    Length*: 0.35mi
    S End: South frontage road at I-70 Exit 310 south of Strasburg
    N End: Jct SH 36 in Strasburg

    Average Annual Daily Traffic (2008): 4400



    BS70
    Deer Trail

    Length*: 0.40mi
    W End: Jct SH 40 in Deer Trail
    E End: East frontage road at I-70 Exit 328 at Deer Trail

    Average Annual Daily Traffic (2008): 1200



    BS70
    Agate

    Length*: 0.35mi
    W End: Jct SH 40 in Agate
    E End: Jct I-70 Exit 340 at Agate

    Average Annual Daily Traffic (2008): 280

    BL70
    Limon

    Length*: 4.26mi
    W End:
    Jct I-70/US 24-40-287 Exit 359 northwest of Limon
    E End: Jct I-70/US 24-40-287 Exit 363 east of Limon
    US Highway Concurrent With: US 24-40-287

    NHS: From I-70 Exit 359 south to the US 24-40-287 intersection.

    Average Annual Daily Traffic (2008):

    • 5200 south of I-70 Exit 359
    • 3700 east of Spur US 24
    • 6700 east of E Ave.
    • 2000 between I-70 Exits 361 and 363

    Guide:
    This BL came about when I-70 was built as a bypass north of Limon. It starts at Exit 359, heads south on Spur US 24 (marked as US 24-40-287), then turns east and goes along Main St. through town. There is short stretch that, once you add them all up, has BL 70, US 24, US 40, US 287, and SH 71 all on it. East of town, it crosses I-70 at Exit 361 then loops back south to end at Exit 361.

    Photo Gallery:

    See my Spur US 24 listing for much more, including maps.

    BS70
    Vona

    Length*: 0.53mi
    S End: Jct I-70 Exit 423 south of Vona
    N End: Jct US 24 in Vona

    Average Annual Daily Traffic (2008): 240

    BL70
    Burlington

    Length*: 1.97mi
    W End: Jct I-70/US 385 Exit 437 south of Burlington
    E End: Jct I-70 Exit 438 east of Burlington

    Average Annual Daily Traffic (2008):

    • 4600 at I-70 west
    • 6000 east of Lincoln St.
    • 4000 at I-70 east

    Guide:
    From Exit 437, BL 70 heads north concurrent with US 385 (Lincoln Ave.), and at Rose Ave., hits US 24. It then heads east with US 24-385, and at 8th Street, US 385 turns off and goes north while US 24/BL 70 continues east. At 7th Street, US 24 breaks off and continues on its historic routing to the northeast on a frontage road, while BL 70 goes due east and ends at Exit 438.

    Photo Gallery:

    • US 24, East Burlington. Westbound on BL 70 in Burlington at its intersection with US 24 on the east side of town. Photo by Dale Sanderson. (December 2003)

    BS76
    Keenesburg

    Length*: 0.47mi
    N End: CR 18 north of I-76 Exit 39 north of Keenesburg
    S End: Keenesburg

    Average Annual Daily Traffic (2008): 2700

    Milepost Guide:

    • 0.00: CR 18 (begin BS 70)
    • 0.18: I-76 Exit 39
    • 0.47: Old US 6 (end BS 70)

    Guide:
    This BS 70 is a spur from Exit 39 due south into Keenesburg, including a section north of I-76 to CR 18. South into town, it uses Market Street, ending at old US 6.

    Main I-76 listing

    BL76
    Fort Morgan
    Brush
    Hillrose
    Merino
    Atwood
    Sterling

    Length*: 51.16mi
    W End: Jct I-76/US 34 Exit 75 west of Fort Morgan
    E End: Jct I-76/US 6 Exit 125 east of Sterling
    US Highways Concurrent With: US 34, US 6

    Average Annual Daily Traffic (2008):

    • 3000 at I-76, Fort Morgan
    • 10,200 east of SH 52
    • 4400 east of CR 24
    • 5300 west of SH 71/Colorado Ave., Brush
    • 2200 south of I-76 Exit 92
    • 980 north of I-76 Exit 92
    • 720 northeast of CR R, Prewitt Reservoir
    • 3500 northeast of SH 63, Atwood
    • 3700 northeast of Front Street, Sterling
    • At US 138 in Sterling (on two one-way streets): 5100 northeastbound, 9900 southwestbound
    • 8800 east of US 138

      Guide:
      BL 76 is one of the longest business loops in the country. It starts at Exit 75 west of Fort Morgan and follows US 34 east through Fort Morgan and Brush. It then turns northeast on Spur 34, the connector road to Exit 92. You might think it would end there, but no, it goes through Exit 92, crossing over the I-76's north side and continuing northeast with US 6. It follows that through Hillrose, Merino and Atwood. It then comes into Sterling, turns east with US 6 and finally ends at Exit 125.

      History:
      There's been some confusion as to whether this was one continuous business loop as described or two separate ones (one from Exit 75 to 92, another from Atwood to Sterling). Robert Halonen and Dale Sanderson have both confirmed it is indeed one continuous business loop. Dale thinks that some of the confusion may be that he recalls in the early 1990s it was marked as two separate loops.

      Continue:

      Last updated 8 June 2014