Alternatives

CDOT has recommended a preferred alternative for the US 6/Wadsworth Boulevard interchange and for Wadsworth Boulevard between 4th and 14th Avenues. The preferred alternative for the US 6/Wadsworth interchange is the Tight Diamond with Loop concept. The preferred alternative for Wadsworth Boulevard from 4th to 14th Avenues consists of six travel lanes, a raised median, and sidewalks.

US 6/Wadsworth Boulevard Interchange

Eight interchange design concepts were studied during the Level 1 screening process. Four of these concepts were screened out due to fatal flaws. The remaining four interchange design concepts were studied during Level 2 evaluation (Tight Diamond, Tight Diamond with Loop , Single-Point Urban Interchange, and Partial Cloverleaf). After detailed evaluation of 20 criteria, the Tight Diamond with Loop was determined to best balance transportation needs with environmental and community impacts.

Examples of the Tight Diamond with Loop interchange type in the Denver metro area include I-25 at both Colorado Boulevard and Castle Pines Parkway.

The proposed interchange at US 6 and Wadsworth Boulevard would provide a loop ramp for the highest volume left-turn movement from westbound US 6 to southbound Wadsworth Boulevard (evening peak). Traffic making this movement would exit US 6 onto a loop ramp as it does today (without stopping at a traffic light to enter Wadsworth Boulevard ). Placing the highest volume left-turn movement on a loop ramp also decreases conflicts and, therefore, increases traffic capacity at other left-turn movements at the interchange.

The eastbound entrance and exit ramps (on the south side of US 6) would be standard ramps, intersecting Wadsworth at a traffic signal. The westbound ramps (on the north side of US 6) would require a traffic signal for southbound Wadsworth Boulevard traffic only; northbound traffic at this location would not require a signal.

The Tight Diamond with Loop would require fairly simple construction staging. It would cost more than a Tight Diamond concept due to the additional right-of-way acquisition required in the northwest quadrant of the interchange but would cost slightly less than a Single-Point Urban Interchange and significantly less than the Partial Cloverleaf design.

Pedestrians and bicycles crossing through the interchange would cross the terminal of the loop ramp and two free-flow right-turn movements without the benefit of traffic signals. Loop ramp crossings present a greater safety concern than right-turn movements because of the speed and sight lines of the vehicles on the loop ramp. To minimize the potential conflicts on the loop ramp, pedestrians and bicycles would be encouraged to cross Wadsworth Boulevard at the south rather than the north ramp intersection.

The US 6 bridge would be wide enough accommodate future expansion of Wadsworth Boulevard or US 6. The loop ramp and westbound entrance ramp, however, would need to be reconstructed if US 6 or Wadsworth were expanded in the future. Constructing a loop ramp that would allow future expansion on Wadsworth Boulevard and US 6 would increase the already-large right-of-way impacts in the northwest quadrant of the interchange

Click here to download a detailed picture of the Tight Diamond with Loop concept. The design of this concept has been refined since the April 29 and May 21 open houses, and includes revised frontage road designs.

Wadsworth Boulevard

The preferred alternative for Wadsworth Boulevard from 4th to 14th Avenues consists of six travel lanes, a raised median, and sidewalks, as shown in the cross section below. This preferred alternative was identified during the Level 1 fatal flaw screening as the only concept that met project purpose and need. Click here to download a detailed picture of the Wadsworth Boulevard preferred alternative design.

click on image to enlarge

Left-turn lanes would be provided in the space available for the median. The median would prevent left turns at mid-block locations and would channel left turns to intersections with cross streets. At most intersections, U-turns would be allowed. No additional traffic signals would be added on Wadsworth Boulevard , except those required at the interchange. Traffic signals would remain at 5th, 10th, and 14th Avenues. Other intersections with cross streets would remain unsignalized. Cross street access to Wadsworth Boulevard at Highland Drive , 8th Place , 9th Avenue , and 13th Avenue would be limited to further improve safety and traffic capacity in the corridor.

The project team is currently refining the design and analyzing impacts of the preferred alternative. The impacts and proposed mitigation measures will be described in the Environmental Assessment, to be distributed for public review in early 2009.

Click here for more information about the Level 1 alternatives screening and Level 2 alternatives evaluation .