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Alternatives

Preliminarily Identified Preferred Alternative

The project team has preliminarily identified the Partial Cover Lowered Alternative as the I-70 East project's preferred alternative. The City of Denver champions this choice of location because of the important role I-70 plays in supporting commerce and providing redundancy in our transportation system in the case of major incidents. This position is shared by the Downtown Denver Partnership and the Denver Chamber of Commerce, as well as Adams County and Commerce City.

The Partial Cover Lowered Alternative was developed in response to the lack of strong public support for the alternatives proposed in the 2008 Draft Environmental Impact Statement. This Alternative adds additional lanes in each direction of the highway to provide better mobility between I-25 and Tower Road, removes the existing viaduct between Brighton Boulevard and Colorado Boulevard, rebuilds I-70 along this segment below grade on the existing alignment, and places a cover on the highway between Columbine Street and Clayton Street next to Swansea Elementary School. The preferred alternative will be constructed with a 75- to 100-year life expectancy.

Specifics about each of these design elements follow:

bulletAdditional Lanes: The additional lanes currently proposed (two lanes in each direction) are necessary to improve operations and assure a safe highway for the traveling public. In fact, CDOT is proposing to make the new lanes managed lanes, which will help them handle congestion over time. Managed lanes can encourage carpooling and transit use and enable more reliable and efficient transit service. Additional lanes allow CDOT and FHWA to maintain a 10-lane template decades into the future. Managed lanes, and their location from I-25 to Brighton Boulevard, are shown in the Lane Continuity Diagram.

bulletRemove the Viaduct: Reconnecting the Elyria and Swansea neighborhoods by removing the viaduct was a key core value identified by residents. We also have heard concerns from residents that they feel unsafe passing under the viaduct. In addition, the viaduct's presence as a visual and psychological barrier has divided these communities for the past five decades. These concerns would be alleviated with the PCL Alternative. Additional modifications are being proposed by the City of Denver to enhance connectivity and sense of place in these neighborhoods.

bulletRebuild below grade: While the lowered highway from Brighton Boulevard to Colorado Boulevard does eliminate the ability of residents to casually cross under the viaduct, the alternative maintains the same number of north-south through-streets as exist today. The project also will provide wider, continuous sidewalks and new street lighting. Some people are concerned about the below-grade highway contaminating water sources, including the South Platte River. CDOT will design the highway so that groundwater will remain untouched. Any groundwater removed during construction will be treated and disposed of per Colorado Department of Public Health and Environment (CDPHE) requirements.

bulletPlace a cover: Many cities (Dallas, Los Angeles, Phoenix, and Seattle to name a few) have partnered with their highway departments to create highway covers that are helping reunite neighbors, revitalize areas, and provide new park space. This is why the City of Denver has included the I-70 East project among its six projects comprising the North Denver Cornerstone Collaborative.

The Partial Cover Lowered Alternative is recommended because it:

bulletIs broadly supported by the public and local officials

bulletImproves safety and mobility for all users of I-70

bulletMeets the purpose, need, goals, and objectives identified for this project

bulletRestores and enhances the community and the social environment

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Existing View

Existing View

Visual Simulation

Visual Simulation

Visual Simulation of the Partial Cover Lowered Alternative (Aerial View)

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Visual Simulation of the Partial Cover Lowered Alternative (Aerial View)

Cross-Section of the Partial Cover Lowered Alternative

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3D Cross-Section of the Partial Cover Lowered Alternative

Typical Section of the Partial Cover Lowered Alternative

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3D Cross-Section of the Partial Cover Lowered Alternative

CDOT uses a complex travel demand forecasting computer model to determine the number of lanes needed to meet future traffic demand on a highway. This model develops traffic forecasts based on projections of household and employment growth around the region. The model also can take into account the projected ridership of the nearby East Corridor rail line. Our travel demand model indicates that the RTD commuter rail line and CDOT's highway improvements are both needed to address the travel demand in this corridor.

The width of the highway is established by summing the number of needed lanes, shoulders, and buffers, and then multiplying by standards established by the Federal Highway Administration. As shown in the graphic above, the proposed cross section for the PCL Alternative that will be presented in the SDEIS is currently 178 feet. The total width, including 46th Avenue on either side, is approximately 300 feet.

Here is a width comparison with other highways in the Denver metro area.

bulletI-25 in south Denver (the TREX project) varies from nearly 400 feet in width, including the RTD rail line, to around 315 feet.

bulletThe new US 36 project currently under construction averages 300 feet in width, with some 350-foot sections.

bulletWhen the new lane is constructed, I-225 will average around 300 feet in width.

Final highway design occurs later in the project development process, after the environmental evaluation process is complete. This is typically when the design is refined and the foot print possibly reduced. Right now, CDOT's intention is to present a scenario for analysis in the EIS that provides the public a full and complete picture of the possible impacts.

Detailed Map of the Partial Cover Lowered Alternative

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Detailed Map of the Partial Cover Lowered Alternative

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Existing View

Existing View

Visual Simulation

Visual Simulation

Visual Simulation of the Partial Cover Lowered Alternative (Elizabeth Street)

View southwest on Elizabeth Street near Swansea Elementary School. Visual Simulation depicts possible enhancements to Swansea Elementary School outdoor spaces.

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Visual Simulation of the Partial Cover Lowered Alternative (view southwest on Elizabeth Street)

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Existing View

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Visual Simulation

Visual Simulation of the Partial Cover Lowered Alternative (Vine Street)

View southeast on Vine Street.

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Visual Simulation of the Partial Cover Lowered Alternative - view southeast on Vine Street

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Existing View

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Visual Simulation

Visual Simulation of the Partial Cover Lowered Alternative (Fillmore Street)

View north on Fillmore Street.

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Visual Simulation of the Partial Cover Lowered Alternative - view north on Fillmore Street

Design Variations for the Partial Cover Lowered Alternative

In addition to the Basic and Modified Connectivity Options for the Partial Cover Lowered Alternative, other design variations to these options are being considered but have not been fully evaluated and remain unresolved issues. These variations were developed to respond to community concerns and to balance community, business, and transportation needs. As part of the public outreach process we will continue to seek feedback from the community, stakeholders, and public agencies on these options and variations. These variations apply only to the Partial Cover Lowered Alternative, and there are no variations being considered for any of the other alternatives at this time. The following links show some of the design variations being considered:

bulletRoundabout interchange at Vasquez Boulevard/Steele Street

bulletDiamond interchange at Vasquez Boulevard/Steele Street

bulletCover options

Alternatives Under Consideration in Supplemental Draft EIS (SDEIS)

I-70 improvement alternatives were initially developed based on input from the public and interested agencies and included transportation solutions that had been considered as part of previous studies in the project area. Through successively more detailed screening, alternatives were refined and evaluated using project goals and objectives. The goals and objectives were established through close coordination with government agencies and the public, and they are based on the project purpose and need. Alternatives found to be unreasonable or ineffective were eliminated from consideration.

Based on the input received since the release of the Draft EIS in 2008 and what was heard from the additional outreach conducted within the community, the project team has been taking a closer look at the options that may be feasible along the Current Alignment. This includes reexamining the reasons previous alternatives were eliminated. This additional analysis resulted in the following alternatives:

Revised Viaduct (North and South)

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Alternative Map - Revised Viaduct (North and South) - click to view detailed information

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Visual Simulation of the North Revised Viaduct Alternative (Aerial View)

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Visual Simulation of the North Revised Viaduct Alternative - Aerial View

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Visual Simulation

Visual Simulation of the South Revised Viaduct Alternative (Elizabeth Street)

View southwest on Elizabeth Street near Swansea Elementary School.

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Visual Simulation of the South Revised Viaduct Alternative - view southwest on Elizabeth Street

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Existing View

Existing View

Visual Simulation

Visual Simulation

Visual Simulation of the North Revised Viaduct Alternative (Elizabeth Street)

View southwest on Elizabeth Street near Swansea Elementary School. Visual Simulation depicts possible enhancements to Swansea Elementary School outdoor spaces.

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Visual Simulation of the North Revised Viaduct Alternative - view southwest on Elizabeth Street

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Existing View

Existing View

Visual Simulation

Visual Simulation

Visual Simulation of the South Revised Viaduct Alternative (Vine Street)

View southeast on Vine Street.

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Visual Simulation of the South Revised Viaduct Alternative - view southeast on Vine Street

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Existing View

Existing View

Visual Simulation

Visual Simulation

Visual Simulation of the North Revised Viaduct Alternative (Vine Street)

View southeast on Vine Street.

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Visual Simulation of the North Revised Viaduct Alternative - view southeast on Vine Street

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Existing View

Existing View

Visual Simulation

Visual Simulation

Visual Simulation of the South Revised Viaduct Alternative (Fillmore Street)

View north on Fillmore Street.

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Visual Simulation of the South Revised Viaduct Alternative - view north on Fillmore Street

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Existing View

Existing View

Visual Simulation

Visual Simulation

Visual Simulation of the North Revised Viaduct Alternative (Fillmore Street)

View north on Fillmore Street.

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Visual Simulation of the North Revised Viaduct Alternative - view north on Fillmore Street

Partial Cover Lowered (North)

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Alternative Map - Partial Cover Lowered (North)

Click to view visual simulations of the Partial Cover Lowered Alternative (above).

Detailed Design Maps for the Alternatives

Detailed design has been completed for the project alternatives that are being evaluated in the SDEIS. View detailed alternative maps:*

bulletNo Action (North Shift) Alternative Map

bulletNo Action (South Shift) Alternative Map

bulletRevised Viaduct (North Shift) Alternative Map

bulletRevised Viaduct (South Shift) Alternative Map

bulletPartial Cover Lowered Alternative Maps  (click to view)

* These are very technical drawings and are considered DRAFT until the completion of the environmental process. If you need assistance downloading the map files or would like help from the project team with understanding the drawings, please call the project hotline at 303.757.9413 and someone will get back to you.

Alternatives Eliminated after 2008 Draft EIS

Realignment Alternatives

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Realignment Alternatives Map (Eliminated after 2008 DEIS) - click to enlarge

Realignment Alternatives were fully analyzed in the 2008 Draft EIS. After more analysis was performed during alternative enhancement and modification, it was determined that the Realignment Alternatives did not meet the project's purpose and need and will not be analyzed in the Supplemental Draft EIS because they are no longer considered reasonable alternatives.

These alternatives divert highway traffic onto local streets; increased vehicle usage of 46th Avenue impacts the sense of neighborhood and community; adds extra mileage out of direction; significantly increases costs. In addition, there was major support for elimination from the public and stakeholders.

Alternatives Evaluated in 2008 Draft EIS

The highway alternatives considered in the DEIS were developed from an extensive list of alternatives suggested by the public, government agencies, and previous studies. Analysis during the DEIS indicated that these alternatives would have fewer adverse effects on the environment and the community, and are more effective at addressing congestion while improving safety, access and mobility than the alternatives eliminated from further consideration. These alternatives have been updated, and are no longer under consideration as presented in the 2008 DEIS. View the alternatives currently being evaluated: Alternatives Under Consideration (above)

ARCHIVE: 2008 DEIS Alternatives (click to view)

Alternative 1 (previously named Alternative A)

Adding new general purpose lanes on existing I-70 alignment along length of corridor. Please click to view a detailed map of this alternative. Click to view enlargement:

Alternative 1 - click to view enlargement

Alternative 3 (previously named Alternative B)

Adding a combination of general purpose lanes and tolled express lanes on existing I-70 alignment, with tolled express lanes added from east of Colorado Boulevard to Chambers Road, and general purpose lanes added west of Colorado Boulevard and east of Chambers Road. Please click to view a detailed map of this alternative. Click to view enlargement:

Alternative 3 - click to view enlargement

Alternative 4 (previously named Alternative C)

New alignment beginning at Brighton Boulevard and extending northeast toward new interchange with I-270 near Vasquez Boulevard, then following existing I-270 alignment southeast to existing interchange with I-70. New general purpose lanes added to I-70 along entire length within project area. Please click to view a detailed map of this alternative. Click to view enlargement:

Alternative 4 - click to view enlargement

Alternative 6 (previously named Alternative D)

As with Alternative 4, re-routing I-70 on new alignment beginning at Brighton Boulevard and along portion of I-270. General purpose lanes added from I-25 to Vasquez Boulevard on realignment, and from Chambers Road to Tower Road on existing alignment. Tolled express lanes added from west of Vasquez Boulevard to Chambers Road. Please click to view a detailed map of this alternative. Click to view enlargement:

Alternative 6 - click to view enlargement

Different options are being evaluated within the alternatives. These options include widening I-70 to either the north or south between Brighton Boulevard and Quebec Street on the existing alignment alternative, and two options for connecting the realignment alternatives to existing I-70 near Brighton Boulevard.

A No-Action Alternative is also being evaluated in the EIS.

Alternatives Eliminated in 2008 Draft EIS

Several highway alternatives have been eliminated from consideration, either through the screening analysis, or after additional engineering and technical analysis.

ARCHIVE: Examples of Eliminated Alternatives (click to view)

Alternative:

Reason(s) eliminated:

I-270/I-76 Reroute

Does not meet the project's purpose and need; results in significant increase in traffic volumes on 46th Avenue; eliminates multiple route choice; increases out of direction travel; requires 12 more miles of highway widening along I-270 and I-76. In addition, many stakeholders have expressed opposition (*see below).

Tunnel

Creates additional safety concerns, has substantially higher construction and operations and maintenance costs, may be a higher security risk, affects the same amount of properties, and has the potential for disturbing or encountering soils or waters that may have elevated concentrations of heavy metals. Click to view the Reasons for Eliminating Tunnel Alternative between Brighton Boulevard and Colorado Boulevard memo.

Below grade

Takes three more years to construct and requires closing access to I-70 at Brighton Boulevard, Steele Street, and Colorado Boulevard during construction. Also requires extensive pumping systems and modifications to the existing groundwater table.

Add level to viaduct

Limits the ability to access the upper level from arterial streets that connect to I-70. Also requires complex construction techniques that result in unreasonable costs as compared to other alternatives. The newly constructed viaduct was not designed for another level.

Enclose I-70 with a roof

Requires complex construction techniques that would result in unreasonable additional costs to provide a cover as compared to other alternatives.

Put I-70 at grade

Inability to provide access to community across new alignment, and need to keep the alignment separated from the existing railroad tracks.

Triple level section of I-70 (below ground)

Limits the ability to access the lower levels from arterial streets that connect to I-70. Also requires unreasonable and complex construction techniques that would include large amounts of excavation causing significantly more impacts to adjacent properties. This alternative would involve unreasonable additional costs to put two levels of the highway below ground as compared to other alternatives.

I-70 above and below with 46th Avenue at ground level

Environmental effects of constructing new alignment through South Platte River, and inability to provide connection back to I-25/I-70 interchange.

High Occupancy Vehicle (HOV) lanes

Lower forecasted usage in the special use lanes than tolled express lanes. Also, tolled express lanes are felt to better justify cost and potential effects.

* Recently, there have been many questions on whether or not CDOT is evaluating an alternative that would realign I-70 around Denver using Interstates 270 and 76. This alternative was eliminated from consideration early in the project process, as documented in the Draft EIS. Additional reasons for not considering this option a reasonable alternative for I-70 East will be included in the next environmental document, the SDEIS, expected to be available in late summer 2013.

bulletARCHIVE: Click to view the archive of alternatives eliminated prior to Oct. 2005.

bulletMORE INFO: Click to view the Alternative Analysis and Screening Process.