In Colorado, U.S. Highway 50 – a coast-to-coast highway that runs from Maryland to California – is a major traffic corridor serving the lower midsection of the state. U.S. 50 provides a vital linkage between the Western Slope, lower Front Range, and the Arkansas Valley, and connects the City of Pueblo to Pueblo West – a community of over 30,000 residents which largely serves as a residential area for a workforce that commutes to Pueblo, Colorado Springs, and Canon City, as well as to the area's many military bases.

Pueblo West residential neighborhoods on both the north and south sides of U.S. 50 are experiencing significant growth; new businesses are also coming to the area. With high volumes of commuter traffic, along with through traffic – including higher than average truck traffic during peak periods in the morning and afternoon commutes – the section of U.S. 50 from Swallows Road to Baltimore Avenue currently experiences peak-hour congestion and above average crash rates. With average annual daily traffic of over 26,000 vehicles – expected to double by 2035 – the signalized intersection at U.S. 50 and Purcell Boulevard is one of the most affected interchanges.

Now, however, a current Colorado Department of Transportation (CDOT) project will significantly improve traffic flow through the busy intersection. The $45.9 million U.S. 50/Purcell Interchange Project, scheduled for completion in 2022, will result in a new grade-separated interchange as well as lengthening of the third westbound travel lane of U.S. 50 between Pueblo Boulevard and Purcell Boulevard. An overpass – a new bridge is a major component of the project – will take highway traffic over Purcell Boulevard without stoppage, since the existing signal will be removed; vehicular, bicycle and pedestrian traffic on Purcell Boulevard will travel underneath the overpass, without the need for crossing U.S. 50. Also part of the project are on-ramps, sidewalks, curbs, gutters, and other improvements.

The project will convert the intersection into a traditional diamond interchange. This design allows for limited impacts on the area, explains CDOT Project Engineer Tim McGhghy. “It allows the interchange to be built with minimal disruption to traffic. Other options would have required extensive ROW and purchasing of established businesses, would not have provided connections for bikes and pedestrians, and would have been more expensive.”

Benefits of the new exchange include alleviation of the traffic bottleneck at Purcell and improvement of safety for the traveling public by reducing the number and severity of projected traffic accidents. There will also be multimodal benefits, as the interchange will include some sidewalk infrastructure and will connect into a developing TAP 3 Trail project, greatly improving bicycle and pedestrian safety.

McGhghy points out, “Switching from a signalized intersection to a grade-separated interchange eliminates rear end collisions and removes left turns and high-speed traffic. Commute times will improve since there will be no signal to stop at for U.S. 50 through traffic. Pedestrian traffic will no longer have to contend with trying to cross mainline U.S. 50 traffic and will have a dedicated sidewalk separated from traffic; the only conflict points will be at the off ramps. Additionally, bike lanes in both directions of Purcell are being built.”

Kirkland Construction of Rye, Colorado, is the project contractor. The design engineer is Atkins. Sub consultants include Stofus, Vivid, SAM, and PK Electrical. Construction services support is being provided by Rocksol and RS&H.

The impetus for the U.S. 50/Purcell Interchange Project was a Planning and Environmental Linkages (PEL) study completed in 2012, focusing on the stretch of U.S. 50 between Swallows Road and Baltimore Avenue. This resulting project is funded by Senate Bill 267/Senate Bill 1, year 2.

“We started a project a few years ago that took the eastbound third lane from Wills to Pueblo Boulevard,” McGhghy relates. “Then we did another project that took it from the boulevard to the top of the hill where the merge point is now.

“There are essentially four phases on Purcell Boulevard and two phases on U.S. 50. The four Purcell phases are traffic shifts to allow the new Purcell Boulevard to be rebuilt and widened for the new interchange. The two U.S. 50 phases are essentially the construction of the new third lane and the shifting of U.S. 50 temporarily onto the new ramps in order to build the embankment fill and the bridge.”

The initial part of the process was building the future exit and entrance ramps alongside the existing intersection; those ramps will be the main route for U.S. 50 until the project's completion. With the traffic shift now completed, construction of the bridge is beginning. In preparation for the bridge work, new traffic lights are being installed where the ramps connect to Purcell Boulevard.

McGhghy reports, “The project has completed three of the four Purcell phases and is currently in the second phase of U.S. 50. Purcell took about a year to complete the widening and the building of the ramps. It will take approximately one more year to construct the fill, bridge, and completed westbound third lane.

Michelle Peulen, CDOT Region 2 Communications Manager, adds, “The general configuration for the traffic shifts were developed during the design phase and then implemented in the field to work with the actual configuration and the current traffic/construction needs of the project. Closures are relayed with emails – we have several hundred local businesses and resident emails on our distribution list – along with weekly lane closure notifications, quarterly project flyers, a texting service, webpage and local VMS panels.”

To ensure stabilization of the foundation of the road base, CDOT is utilizing wick drains on the interchange project. These prefabricated vertical drains – geotextile filter-wrapped plastic strips with molded channels, placed into the ground using hydraulic excavators and vibratory attachments – filter out soil particles and offer groundwater a drainage path; their use on the project has accelerated the soil compaction process by reducing the time it takes to remove moisture from the ground.

As McGhghy points out, the use of wick drains eliminated the need to compact the soil by traditional methods, which would have required bringing in dirt, using compaction equipment to settle the dirt, and delaying project progress significantly. “The existing embankment the new interchange will be built on has the potential to settle up to 9 inches once the new embankment for the overpass is built. Without placing the wick drains, that settlement/consolidation could take up to three years to happen. Using the wick drains, it is estimated the settlement/consolidation will be completed in three months.

“It was decided the cost for the wick drains is minimal compared to the user cost to put the project on hold for settlement to occur naturally,” he explains, adding, “Wick drain installation is not common. This is its second use in the region; the first use was on Cimmaron and I-25 in Colorado Springs.”

Asked about other challenges the interchange project has presented, McGhghy says, “Shallow groundwater has made it a challenge to install many of our utility items. Along with the groundwater, the project has encountered several areas where the bedrock is only a few feet deep and has required lengthy times of rock excavation in order to install utilities.

He reports that the project is currently installing the majority of the wick drain system, and preparing to start the bridge foundations and do the majority of the embankment fill for the bridge.

U.S. 50 serves as a regional arterial for commerce, trucking, farming – and tourism, bringing visitors to Colorado’s mountains and attractions including the Royal Gorge, from several surrounding states. As initial construction on the U.S. 50/Purcell Interchange Project got underway, Colorado Transportation Commissioner Bill Thiebaut stated, "U.S. 50 is of vital importance to the residents of Pueblo West as well as the traveling public.”

With the project now well into another major phase, McGhghy reports, “With the current traffic shift that has put traffic onto the ramps, we are already seeing operational improvements at the intersection.”

Says Peulen, “The secret of Pueblo West is out. It is a great place to live, work and recreate. Many of us on the project team call this community home, and this project will make a lasting impact on the safety and mobility of U.S. 50 and Purcell Boulevard for generations.”