Denver's 470 Saga

The Story of I-470, C-470, E-470, W-470, and the Northwest Parkway
I-470 C-470 E-470 NW Pkwy

JUMP directly to the history of E-470


Why does Denver have a 470 Saga? It all has to do with a proposed Interstate that didn't get built. The state then built a highway where the Interstate would have gone, and two toll roads are also in the mix. I should probably be saying "Denver's 470s" (plural) because, before all was said and done, there were four different 470s:

It should be stressed that everything that has to do with Denver's 470 Saga is connected to Denver's slowly growing beltway. All of the roadways I profile here would have been some segment in Denver's beltway.

The Need Arises

It all started back in the late 1960s with the southwest side of the Denver metro area going through a growth boom. This boom caused the Colorado Department of Highways (CDH, now CDOT) to send a proposal to the Federal Highway Administration (FHWA) for a new southwest metro Denver cicumferential 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 and heading southeast and then east to end somewhere around I-25 and County Line Road. The advantage of having this highway be part of the Interstate system is that the feds chip in 90% of the construction costs of Interstate highways. The Federal Highway Act in 1968 specifically mentions I-470 and added the 26 miles of I-470 to the Interstate and Defense Highway System. I-470 was officially approved December 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 is provided. On September 4, CDH and FHWA accept a corridor location preliminary design study by the Ken R. White Co.

On January 7, 1970, a public hearing is held at Bear Creek High School. About 250 attend, but no mention is made of how they like the plans. On January 8, the Denver Regional Council of Governments (DRCOG) supports I-470, and recommends that CDH work closely with "the Council's Subarea Design Team." On February 2, CDH requests formal approval from FHWA for route location and preliminary design. On June 11, the Ken R. White Co. is authorized to do environmental studies in compliance with the National Environmental Policy Act of 1969. On December 22, CDH prepares the Draft Environmental Statement and submits it to FHWA.

On June 14, 1972, the Final Environmental Impact Statement is submitted to FHWA.

FHWA Response

It took a while, but FHWA and other government agencies came back with the response to the FEIS on May 24, 1973. But, it wasn't favorable. General Benjamin O. Davis, Jr. (who is Assistant Secretary for Environmental, Safety, and Consumer Affairs) questions the FEIS. FHWA asks CDH to prepare a supplement. On June 20, 1974, the FHWA Division Engineer returns the supplement to CDH 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, CDH sent the Supplement to the FEIS for review and approval, as well to the Colorado Department of Health.

Anti-I-470 Momentum Builds

Richard Lamm is elected Governor in 1974, and part of his platform is to "drive a silver stake" through I-470.

In January 1975, both the Colorado Department of Health and the Environmental Protection Agency respond to CDH's air quality analyses. They both said they came to conclusions different from the CDH. In April, the Governor's Office requests information from CDH 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 announces official state opposition to I-470. In a press conference on May 5, Lamm directs all work on I-470 to cease immediately.

The Governor's Commission

In 1975, the debate on whether to build I-470 becomes extremely heated and emotional, and begins to polarize the state. So, on June 30, Gov. Lamm appoints a commission to sort things out and make recommendations. This group becomes known as the I-470 Ad Hoc Commission. They held four meetings from October to November, 1975 to discuss topics such as land use, air quality, socio-economic impacts, and transportation needs.

CDH Does Studies

In November 1975, CDH began a two-part program to examine transportation issues for the southwest Metro. Included in the program was CDH, DRCOG, and the Regional Transportation District, which runs the buses and light rail in Metro Denver. 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, CDH said that the Ad Hoc Commission should consider Alternatives 2, 5, 7, and 11 for detailed analysis. The Commission agreed. But, on March 19, the Commissioned asked CDH 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. As you will find out below, this is important because it contains a provision that allows federal money that has been allocated to Interstate Highways to be diverted to something if the Interstate is 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 said 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 CDH studies, local government requests, and citizen input, the Commission made a recommendation. On December 17, 1976, the I-470 Ad Hoc Commissioned 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 after that meeting.

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 these five things:

  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 eleven 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 CDH.

On January 20, 1977, the CDH 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 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 CDH building a major highway facility between I-25 and SH 83 (Parker Road). This didn't happen, and as we shall see later, E-470 took its place.

All of these city and county resolutions had four conditions:

  1. That CDH budget preliminary engineering funds for the three substitute projects prior to submission of the I-470 withdrawal. This was done.
  2. That CDH and 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 CDH May 13.
  3. That any additional federal funds left over 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, but I can't say that for sure.


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.

So What's the Deal with These Toll Roads?

C-470 was built with the idea that other roadways would connect to it for more beltway. Through the 1980s and '90s, CDOT didn't want to touch the rest of the beltway with a ten-foot pole, so that means that cities and counties had to step in to build it. However, these are major highway facilities that require mega moola, so toll roads came to be the viable option.

Extension 470

The next area so that saw 470 beltway interest was the eastern metro. In 1983, the Arapahoe County Airport Influence Area Transportation Study recommends an eastern half of a beltway be built, and that it connect with C-470 in the south to create an extension of it. A group of landowners then organizes a public/private coalition to advocate the southeast part of the beltway, labeled "E-470" for Extension 470. Interest initially is only in Arapahoe and Douglas counties, but Adams County soon joins. Shortly thereafter, the E-470 Task Force is organized, which includes the counties of Adams, Arapahoe, and Douglas. Non-landowner citizens are included, and the City of Aurora joins soon after. In July 1983, the Task Force commissions an alignment and financing study, to be completed by January 1985. CDH and DRCOG make technical contributions, but do not get a further involved in the project.

In 1985, discussions between the City of Denver and Adams County progress for a new airport. The area northeast of Stapleton Airport is the focus, and its proximity to the proposed E-470 is considered in the study. The E-470 alignment study comes back, and make recommendations on alignment, institutional structure, and financing. At that time, tolls are not recommended.

Finally, in February 1985, the E-470 Authority is created by an intergovernmental agreement between Adams, Arapahoe, and Douglas counties. The City of Aurora joins in July. The Authority is 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 hires an executive director, then, in early 1986, a chief engineer. Tolls become more of an option as the area experiences an economic downturn. The only other financing strategies are home rule city power to levy tolls, county authority to issue bonds, and an 1883 statute for private toll roads, because the Authority cannot incur debt in its own name. In Spring 1986, the Authority hires legal, financial, and engineering consultants. In August 1986, Arapahoe County issues $772M in "Capital Improvement Trust Fund Highway Revenue Bonds" on behalf of the Authority.

Finally, in August 1987, the Public Highway Authority Act becomes law, and the E-470 Authority can move forward. More can be found on that law on the Public Highway Authority page. In January 1988, the E-470 Public Highway Authority is officially chartered as a "political subdivision" of the state. There is a newly structured board, consisting of one elected member from each jurisdiction. In August 1988, the board adopts a financing plan. It calls 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 can pay for construction of the next. In November, the voters approved the registration fee 58-42, and ground breaking is held on Segment I in December. $68M from the bonds is released for construction. E-470 Segment I opens in June 1991.

Over the next few years, the E-470 Authority gets ready 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. The status of E-470 from Segment I onward can be found on my E-470 page.

Western 470

Since C-470 and E-470 take care of all but the northwest part of Denver's beltway, that still leaves a gap in it. Following the model of E-470, the W-470 Authority is 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 is officially designated in by DRCOG in December 1987, and W-470 is part of the 2010 Regional Transportation Plan. The Authority is officially chartered as a "political subdivision" of the state in May 1988. The tollway is estimated to cost $283M-$535M.

However, an election to authorize the $10 annual vehicle registration fee is 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 is successful in fomenting opposition based on alleged environmental degradation, unchecked growth, and unfair taxation. The defeat also reflects differences in policy between Boulder County and Jefferson County and their constituent cities." (DOT Mandated Studies on Tolls and Tunnel & Public Highway Authorities, page 2-10)

The problems for W-470 only got worse. An opposition group, W-470 Concerned Citizens, brought a lawsuit in spring 1989 alleging that the Authority promoted the vehicle registration fee in violation of state law. However, the suit is ultimately dismissed. Then, in 1992, the W-470 Authority is forced to suspend operations based on its inability to obtain working capital or long term financing. The board votes to close shop on July 15, 1992. However, the Authority is not officially disbanded. It can be started up 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 Denver's 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, mostly thanks to Broomfield's relentless efforts.

Broomfield has always been the Parkway's biggest supporter. The city has been quietly 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, someone from 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 current Northwest Parkway Authority.

The Northwest Parkway Authority, formed under the Public Highway Authority Act in June 1999, includes 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 November 24, 2003.

See the PHA Tollway page for more on the Northwest Parkway.

Golden to Broomfield

Dating back to W-470, there has always been a desire for the northwest beltway to continue southwest from Broomfield through Arvada and Westminster, going from US 36 at Interlocken south between Rocky Flats and Standley Lake, west along SH 72, then turning south on SH 93, and somehow going through Golden to hook up with I-70 at SH 470.

Westminster and Arvada want to see the beltway built as a way to get through traffic off city streets. However, Golden is not as enthusiastic. The mood there since about the very beginning has been that the belway will bring noise, pollution, and traffic with no benefits. Golden residents had a public meeting back in early September 1997. Seventy-five people attended the meeting, and everyone there was against it. The Golden City Council back then also was against it.

The Broomfield/Boulder County section of the beltway ended up being built (Northwest Parkway) thanks to the efforts of Broomfield. A section along C-470 between US 6 and I-70 was constructed as a state highway and opened the last week of August 2000. However, the Jefferson County segment through Westminter, Arvada, and Golden continued in a holding pattern up until August 2000, when it was tabled indefinitely. Instead, the players involved, Jefferson County, Arvada, Golden, Lakewood, Wheat Ridge, and Westminster, decided to put off construction of it for 20 years and instead expand existing streets and highways. SH 93, SH 72, and Indiana Street would be expanded to four lanes and right-of-way dedicated for possible future expansion.

That changed in late 2002 when Arvada and Jefferson County decided to revive the beltway idea and create a 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. CDOT's in-house toll authority, the Colorado Tolling Enterprise, put up the $8M for an environmental impact statement, and would have built the remainder of the beltway if that was the perferred alternative. However, in June 2008 CDOT threw in the towel on the study. There was no funding on the horizon for any option, and the stakeholders involved (read: the cities) couldn't reach consensus (to say it nicely). So the study was halted and CDOT washed its hands of the northwest beltway.

In a way, Denver's beltway has come full circle (pun intended). We've gone from the state doing it (C-470) to toll authorities doing it back to the state doing in the course of 20 years. Here's a tell-tale quote from Rich Ferdinandsen, who was chairman of the W-470 Authority when he was Jefferson County Commissioner in the late 1980s:

The whole process of planning transportation in the metro area is a very convoluted, bizarre, Byzantine process. Between the municipalities, counties, DRCOG, the federal government, the environmentalists, the regional Air Quality Council, and then on top of that the State Highway Department and RTD, everybody and their dog participates and can virtually stop a project or influence it or whatever.


Last updated 8 August 2008