Anyone who ventures through the intersection of Mineral Avenue and Santa Fe Drive in the morning or afternoon rush hour knows that it is not ideal. More than 60,000 vehicles per day go through this intersection and it is only projected to grow as future development in Douglas County and southwest Littleton come out of the ground. The basic layout of the intersection has been in place for more than three decades with only small changes, while nearly 300,000 new residents have moved in around the south metro area.
Over the last 12 months, the city has led a charge to look at future options and costs for fixing this challenging location. Constraints on solutions are high including the RTD light rail station and parking, existing railroad lines, grade changes as roads approach the intersection, environmental concerns, and the South Platte River nearby. In order to gauge public sentiment, the city utilized consulting firm HDR to start public outreach and listen to ideas and alternatives from those that drive this intersection every day. HDR, in consultation with city staff, Colorado Department of Transportation (CDOT), plus Arapahoe and Douglas Counties, developed a series of more than a dozen long-term solutions to remedy traffic loads today and accommodate future growth. Of these options, two rose to the surface as viable and within reasonable cost expectations. The first is a tight diamond interchange, a common roadway feature; while the second is a Single Point Urban Interchange, similar to Belleview and Santa Fe. Both of these solutions are estimated to cost $90 million.
The capability to build the ultimate solution relies on an enduring partnership with all the cities and counties in the area and a host of federal funding via CDOT. The process to acquire the capital necessary for such a project is likely at least a decade away. All the partners along the Santa Fe corridor are moving toward planning future solutions when a Planning and Environmental Linkages study kicks off in the next year, developing a multi-year plan to upgrade and enhance Santa Fe Drive. The city also looked to develop a model for an immediate fix to relieve congestion today and also prepare for the ultimate solution. The two models that rose to the top are an alternative that adds road loops in the southwest and northwest corners (Quad Roads) or a Continuous Flow Intersection that modifies how cars turn through the intersection opening up valuable cycle time with the traffic signals. The improvements would add over 50 percent capacity to the interchange with both costing between $9M -$15M.
At this point funding for either the short or long-term solution is not in place and will take years to move forward. The city has submitted a competitive application with The Denver Regional Council of Governments (DRCOG) as part of the Statewide Transportation Improvement Plan seeking funding for 80% of the immediate solution. The city will be competing with more than 100 projects submitted as part of the 8-county DRCOG region. The ranking process will be complete this summer and the city will know the amount of federal funding to be added to the project. The regional impacts of interchange improvements are clear and with support from cities around the region the City of Littleton is hopeful to get the grant.