Where's Our Beltway?

Why Doesn't Denver Have a Completed Metropolitan Beltway ?

It all has to do with a proposed Interstate that was never built. The State of Colorado built a highway where the Interstate would have gone Subsequently, two toll roads were built (E470 and Northwest Parkway).  Now there are four different “470's:” Interstate 470, which was never built. Colorado 470 (C-470), which was built by the State in place of Interstate 470. C470 runs from I-70 at Golden on the west and I-25 and Yosemite on the south east. Extension 470 (E-470), is a Non-State tollway that is in service and runs approximately from the southeast end of C-470 and north to I-25 in Thornton. The Northwest Parkway, another Non-State tollway is in service and runs approximately from I-25 on the north to Broomfield on the west. 

The Need Arises 

The beltway saga began in the late 1960’s when southwest metropolitan Denver experienced a growth boom. This boom caused the Colorado Department of Transportation (in the late 1960s this department was called the Colorado Department of Highways but for the purposes of this writing will be referred to as CDOT) to send a proposal to the Federal Highway Administration (FHWA) for a new southwest metro Denver circumferential route (partial beltway), which was to be part of the Interstate system. This new highway would be called I-470 and would have the general route of starting at I-70 near Colfax Avenue, heading southeast and then east, to end somewhere around I-25 and County Line Road. The advantage of having this highway as part of the Interstate system is that the Federal government contributes 90% of the construction costs of Interstate highways. The Federal Highway Act in 1968 specifically mentions I470 and added the 26 miles of I-470 to the Interstate and Defense Highway System. I-470 was officially approved in December of 1968. 

Everything's Going Along Fine 

In 1969, the Denver Metropolitan Area Transportation Study adopted I-470 into its plans. I-470 is also shown on the comprehensive plans of Jefferson and Arapahoe Counties. On March 13, 1969, preliminary engineering funding was provided. On September 4, CDOT and FHWA accepted a corridor location preliminary design study prepared by the Ken R. White Company. On January 7, 1970, a public hearing attended by about 250 people was held at Bear Creek High School. On January 8, the Denver Regional Council of Governments (DRCOG) voted to support I-470, and recommended that CDOT work closely with the Council's Subarea Design Team. On February 2, 1970, CDOT requested formal approval from FHWA for route location and preliminary design. On June 11, 1970, the Ken R. White Co. was authorized to do environmental studies in compliance with the National Environmental Policy Act of 1969. On December 22, 1970, CDOT prepared the Draft Environmental Impact Statement and submitted it to FHWA. On June 14, 1972, the Final Environmental Impact Statement was submitted to FHWA. 

FHWA Response 

On May 24, 1973, the FHWA and other government agencies responded to the FEIS. The response was not favorable. The Assistant Secretary for Environmental, Safety, and Consumer Affairs questioned the FEIS. FHWA asked CDOT to prepare a supplement. On June 20, 1974, the FHWA Division Engineer returned the supplement to CDOT with more suggestions for changes. The problem that came up was that FHWA found “significant deficiencies and questions existed regarding alternatives to the use of public lands under Section 4(f), consistency with requirements of the Federal Clean Air Act, and effects on land use.” Finally, on August 16, 1974, CDOT sent the Supplement to the FEIS for review and approval, as well as to the Colorado Department of Health. 

The Silver Stake: Anti-I-470 Momentum Builds 

Richard Lamm was elected Governor in 1974, and part of his platform was to “drive a silver stake” through I-470. In January 1975, both the Colorado Department of Health and the Environmental Protection Agency responded to CDOT’s air quality analyses. Both came to different conclusions than CDOT. In April of 1975, the Governor's Office requested information from CDOT on the impacts of I-25 and I-225 on land use patterns and growth. That information was sent, and on April 24, the Governor announced official State opposition to I-470. In a press conference on May 5, Lamm directed all work on I-470 to cease immediately. 

The Governor's Commission 

In 1975, the debate on whether to build I-470 became extremely heated and emotional, and began to polarize the State. On June 30, 1975, Governor Lamm appointed a commission to sort things out and make recommendations. This group became known as the I-470 Ad Hoc Commission. They held four meetings in October and November, 1975 to discuss topics such as land use, air quality, socio-economic impacts, and transportation needs. 

CDOT Does Studies 

In November 1975, CDOT began a two-part program to examine transportation issues for the southwest metropolitan area. Included in the program was CDOT, DRCOG, and the Regional Transportation District (RTD). The result of this was the I-470: Preliminary Screening Process Report, released in January 1976. It studied 23 criteria, including social, environmental, land use, and transportation. This report included 11 alternatives to what could be done in the southwest metro: 1. Do nothing. Cost in 1975 dollars: $600,000 in preliminary engineering already done. 2. Grid. Extend and enlarge 161.04 miles of existing city arterial street system. $284.3M 3. Diagonal Route. Build a 22.254-mile expressway with some interchanges from I-70 near Rooney Ridge Bridge to County Line Road near McLellan Reservoir, then along County Line Road to I-25. $75.8M 4. Grid/Outer Route. Build a freeway along what is now C-470 and enlarge existing city arterial grid. $367.5M 5. Airport Diagonal. Build a 23.48-mile expressway similar to current C-470, except don't swing as far southwest, so it goes by Columbine Airport. $79.5M 6. Outer Route Expressway. Build a 25.568-mile expressway along what is now C-470. $62.5M 7. Outer Route Freeway. Same as #6, except it's a freeway. $83.2M 8. Hampden/Kipling Route. Build a 15-mile expressway from West 6th Ave. at Kipling St. south on Kipling to Hampden Ave., then east along Hampden to I-25. $85.9M 9. Hampden Diagonal. Build a 16.74-mile expressway from I-70, southeast to Hampden Ave. at Simms, then east to I-25. $90.8M 10. Belleview/Diagonal. Build a 18.334-mile from I-70 southeast to Belleview Ave., then east to I-25. $87.4M 11. Outer Route/Wadsworth/Diagonal. Same as #10 to Belleview, then south along Wadsworth Blvd. to County Line Road and east to I-25. $79.2M The Preliminary Screening Process Report was distributed in January 1976. The Ad Hoc Commission then recommended on January 30 that Alternatives 2, 3, 5, 6, and 7 should receive further review. On February 6, CDOT said that the Ad Hoc Commission should consider Alternatives 2, 5, 7, and 11 for detailed analysis. The Commission agreed; however, on March 19, the Commission asked CDOT to consider a new alternative: 12. County Line Road/Santa Fe/Hampden. Build a 27.2-mile expressway from I-70 southeast to Hampden Ave., east to Santa Fe Drive., south to County Line Road, then east to I-25. Meanwhile, the 1976 Federal Highway Aid Act became law. This is important because it contained a provision allowing Federal money allocated to Interstate Highways to be diverted to other projects if the Interstate was withdrawn from the Interstate Highway System. In September 1976, the I-470: Detailed Assessment Report was distributed. Five public meetings were held, at which the results of the report were presented and discussed. It concluded that none of the four alternatives (2, 5, 7,11) had adverse environmental or land use consequences. But, it stated that no alternative solved the problems of the rapidly growing southwest Metro. While I-470 was meant as a bypass highway, the traffic projections showed very little of the traffic using it as “bypass” in nature. Also, the requirement to build it to Interstate standards would require lots of land and resources, and that had become unacceptable to some people. Projected traffic growth and congestion would not be alleviated by the building of one single highway facility. 

Consensus on Withdrawal 

Since none of the alternatives in the Detailed Assessment Report were superior to any of the others, the Ad Hoc Commission and CDH joined forces to find something better. Using CDOT studies, local government requests, and citizen input, the Commission made a recommendation. On December 17, 1976, the I-470 Ad Hoc Commission unanimously recommended that I-470 be withdrawn from the Interstate and Defense Highway System. The money that had been earmarked for I-470 this whole time ($175.87M, $158.29M of which was Federal) would then be transferred to other projects, per the 1976 Federal Highway Aid Act. The Commission was then disbanded. The Commission’s recommendation was based on the fact that none of the alternatives in the reports would solve the transportation problems of the southwest metro. While one facility would require a major expenditure, several smaller facilities would have greater flexibility and be able to improve traffic along several corridors. The Commission concluded that the Interstate would have adverse impacts on parks and historic resources, plus I-470 would not be essential to the completion of the Interstate System. The Department of Defense also said that I-470 was not essential (it is after all the Interstate and Defense Highway System). The Commission's final recommendation was to do the following: 1. Pursuant to 23 USC 103(e)(4), I-470 should be withdrawn from the Interstate and Defense Highway System and its funds be transferred to other transportation projects. 2. Build a “parkway” along the route of Alternative #7 at a cost of $74.1M (Federal share $59.3M). 3. Make improvements to South Santa Fe Blvd. (US 85) at a cost of $34.4M (Federal share $27.5M). Improvements would include interchanges and 11 railroad grade separations. However, Santa Fe should not be expanded past six lanes to encourage public transit. 4. Make improvements to South Kipling Street at a cost of $12.8M (Federal share $9.6M). Improvements include expanding Kipling to four lane arterial and extending it south to the new Parkway. 5. Transfer the remaining $61.2M in Federal funds to other transportation projects, to be determined through the Metropolitan Planning Organization (part of DRCOG), with concurrence of the Governor and CDOT. On January 20, 1977, CDOT passed a resolution in favor of the Commission’s recommendations. On April 20, the Metropolitan Planning Commission passed a resolution accepting the withdrawal and the three main substitute projects. In March and April, the counties of Arapahoe, Douglas, and Jefferson, as well as the cities of Denver, Lakewood, and Littleton all passed resolutions supporting the withdrawal of I- 470 and the substitute projects. However, the Douglas County resolution was contingent upon CDOT building a major highway facility between I-25 and SH 83 (Parker Road). This did not happen. As discussed later, E-470 took its place. All of these city and county resolutions had four conditions: 1. That CDOT budget preliminary engineering funds for the three substitute projects prior to submission of the I-470 withdrawal. This was done. 2. That CDOT and the City of Lakewood agree to transfer a segment of SH 26, Alameda Ave., from Sheridan to Kipling from the State back to the City, and that new segments of Kipling St. be part of the state highway system. This was approved by Lakewood April 25, 1977, and by CDOT May 13. 3. That any leftover Federal funds be spent on transportation projects as determined by the Metropolitan Planning Organization. This was already taken care of in 23 USC 103(e)(4). 4. That FHWA give approval of the three substitute projects prior or simultaneous to approval of I-470 withdrawal. This was done June 23, 1977. One note: The United States Code that that is mentioned, 23 USC 103(e)(4) appears to no longer exist. Looking at the rest of the code, it appears to now be 23 USC 103 (b)(8)(4). It was probably changed as part of the National Highway System Designation Act. 


The southwest parkway, or Centennial Parkway as it came to be known, was the major substitute project for the I-470 funds. As per the Ad Hoc Commission's recommendation, it was built along the route of Alternative #7. This is today's Colorado Highway 470. Construction began in 1980, the first segment opened in 1985, and the whole thing was completed by 1990. It should be noted this is several years earlier than would have been possible had 470 remained part of the Interstate system. C-470, as it came to be called, was to be built as a four lane freeway, just like I-470 would have been, but also has three park-and-ride facilities. At the northwest end of C-470 with I-70 Exit 260, the interchange was built to accommodate a possible extension of the beltway further north. 

How Did Toll Roads Come to Pass? 

C-470 was built with the idea that other roadways would connect to it to create a beltway. Through the 1980s and 90s, CDOT was not willing to pursue connections. Therefore, cities and counties stepped in. Because of the expense of these projects, toll roads became the most workable solution. 

Extension 470 

The next area to show interest in a 470 beltway extension was the eastern metropolitan area. In 1983, the Arapahoe County Airport Influence Area Transportation Study recommended that an eastern half to the beltway be built, connected to C-470 on the south. A group of landowners organized a public/private coalition to advocate the southeast part of the beltway, labeled “E-470” for Extension 470. Initial interest was only shown by Arapahoe and Douglas counties, but Adams County soon joined in. Shortly thereafter, the E-470 Task Force was organized, which included the counties of Adams, Arapahoe, and Douglas. Non-landowner citizens were included, and the City of Aurora also joined. In July 1983, the Task Force commissioned an alignment and financing study, to be completed by January 1985. CDOT and DRCOG made technical contributions, but did not get a further involved in the project. In 1985, discussions between the City of Denver and Adams County progressed to build a new airport. The area northeast of Stapleton Airport was the focus of study, and the area’s proximity to the proposed E-470 was considered. The E-470 alignment study made recommendations on alignment, institutional structure, and financing. At that time, tolls were not recommended. Finally, in February 1985, the E-470 Authority was created by an intergovernmental agreement between Adams, Arapahoe, and Douglas counties, joined by the City of Aurora in July. The Authority was made up of a governing board of ten elected officials: three from each county and one from Aurora. In the fall of 1985, the Authority hired an executive director and then a chief engineer. Tolls became an option that was seriously considered as the State began to experience an economic downturn. The only other financing strategies were home rule city power to levy tolls, county authority to issue bonds, and an 1883 statute for private toll roads, because the Authority could incur debt in its own name. In Spring 1986, the Authority hired legal, financial, and engineering consultants. In August 1986, Arapahoe County issued $772M in “Capital Improvement Trust Fund Highway Revenue Bonds” on behalf of the Authority. Finally, in August 1987, the Public Highway Authority Act became law, and the E-470 Authority moved forward. In January 1988, the E-470 Public Highway Authority was officially chartered as a “political subdivision” of the State of Colorado. A newly structured board consisted of one elected member from each jurisdiction. In August 1988, the board adopted a financing plan calling for a $10 per year vehicle registration fee, and for the roadway to be built in phases so that the toll revenue from one phase could pay for construction of the next. In November, the voters approved the registration fee 58-42, and ground breaking was held on Segment I in December. $68M from the bonds was released for construction. E-470 Segment I opened in June 1991. Over the next few years, the E-470 Authority prepared to work on Segments II, III, and IV of E-470. In June 1991, Morrison-Knudsen was selected as the sole design-build contractor for the remaining segments. 

Western 470 

With the completion of C-470 and E-470, all but the northwest section of the beltway was completed. Following the model of E-470, the W-470 Authority was created by an intergovernmental agreement between Adams and Jefferson counties, and the cities of Arvada, Broomfield, Golden, Lafayette, Louisville, Superior, and Westminster in April 1987. A corridor alignment for W-470 was officially designated by DRCOG in December 1987, and W-470 became part of the 2010 Regional Transportation Plan. The Authority was officially chartered as a “political subdivision” of the State in May 1988. The tollway was estimated to cost between $283M-$535M. However, an election to authorize the $10 annual vehicle registration fee was defeated by a 4-to-1 ratio in February 1989. Why was it defeated? One factor might be that the W-470 vote was held during a special election, rather than a general election as it was with E-470. Also, a coalition of environmental and community-based organizations was successful in fomenting opposition based on alleged environmental degradation, unchecked growth, and unfair taxation. The defeat also reflected differences in policy between Boulder County and Jefferson County and their constituent cities. The problems for W-470 only got worse. An opposition group, W-470 Concerned Citizens, brought a lawsuit in spring of 1989 alleging that the Authority promoted the vehicle registration fee in violation of State law. However, the suit was ultimately dismissed. Then, in 1992, the W-470 Authority was forced to suspend operations based on its inability to obtain working capital or long-term financing. The board voted to close shop on July 15, 1992. However, the Authority was not officially disbanded but could be started again at the discretion of the member jurisdictions. At the time it closed down, the Authority had $800,000 in assets, almost all in planning, engineering, and financing studies. Also, Golden and Broomfield had purchased land on behalf of the Authority for right-of-way, but that reverted to the prior owners when it was not used by the W-470 Authority by 2000. 

Northwest Parkway 

With the demise of W-470, the northwest metro was still without its segment of the metropolitan beltway. Throughout the 1990s the various jurisdictions involved went around and around about what to do. The one item that did get accomplished was the segment of the beltway from US 36 to I-25, called the Northwest Parkway. Broomfield was the biggest supporter of completing the Parkway, acquiring the right-of way for years and orienting comprehensive land use plans around it. In mid-September 1998, the Northwest Parkway Project Non-Profit Corp. became essentially an arm of Broomfield, run by the mayor, the city manager, a city council member, a representative of the Interlocken Business Park, and Steve Hogan, former Executive Director of the E-470 Authority. That coalition laid the groundwork for the formation of the Northwest Parkway Authority. The Northwest Parkway Authority, formed under the Public Highway Authority Act in June 1999, included Broomfield, Lafayette, and Weld County. The Authority issued bonds with private money, so no vote was required, and began construction on the US 36 to I-25 tollway in 2001. The tollway opened on November 24, 2003. 

Broomfield to Golden 

The missing section of the beltway, from the end of the Northwest Parkway in Broomfield to the beginning of C-470 in Golden, is a glaring break in an otherwise complete beltway system. Completing the beltway was integral in the plans of Jefferson County cities including Arvada, Westminster, and Golden, all of whom were signatories on the W470 Authority. As part of the planning phase, Golden lobbied to move Highway 93 off of Washington Street, knowing that the future beltway alignment would follow Highway 93. Therefore 93 was built outside of the City of Golden. Later, Golden lobbied the State of Colorado and received Federal funds to build the “Golden Link”, connecting C470, I-70, and US 6, with exits at all four corners to create commercial and retail value for that property. Golden planned for the beltway since at least 1983. Their 1992 Transportation Plan re-endorsed its 1983 plan, including reservation of a 300 foot of right of way along Highway 93. Only after Golden began developing residential housing adjacent to the 300 foot right-of way along CH 93 did they begin to oppose the project. 


* SH 93 follows Washington Street alignment through downtown Golden § Golden lobbies CDOT and seeks support from surrounding communities to realign SH 93 off of Washington Street § Golden’s Comprehensive Plan recognizes future beltway completion along the proposed realignment of SH 93 


* SH 93 realigned to current configuration and directly intersects SH 58 and US 6. Referred to by Golden as the SH 93 Bypass § 300’ of right of way reserved for beltway 

* Golden’s comprehensive plan recognized beltway completion and acknowledges that the beltway will follow the SH 93 Bypass and ultimately become a six lane facility but initially will be limited to four lanes.

*No development exists adjacent to the corridor but building permits are taken out 


* Golden permits residential commercial and institutional use to build around realigned SH 93 corridor  Golden’s comprehensive plan is sanitized of all references to beltway In late 2002, the City of Arvada and Jefferson County created a non-profit authority—the Jefferson Parkway Authority—to build a toll road. However, they reached a compromise with CDOT in April 2003 and stopped their efforts, letting the State take the lead. 

Since that time, CDOT has been conducting an extensive Environmental Impact Study (EIS) looking at various alternatives to resolve the traffic problems created by the ‘missing link’ of the Denver Metropolitan Beltway.

Much of the information on this page is courtesy of Matthew E. Salek, Civil Engineer.