In a nice example of city and state governments working together, what was once two separate infrastructure projects have been combined into one.

The City & County of Denver had lined up funding for the construction of the Central Street Promenade, a bike/ped project along the southeast side of Central Street in Lower Highland between 20th and 16th Streets. The project didn’t extend the additional block to 15th Street because Denver knew that CDOT had tentative plans to rebuild the aging 15th Street bridge over I-25, so the block from 16th to 15th was excluded to prevent building something that might be incompatible with CDOT’s future bridge design.

Later in 2010, however, CDOT decided to bump their 15th Street bridge reconstruction plans to the top of the priority list as part of a broader I-25 widening and lane reconfiguration project from 20th Street to Speer Boulevard. Since Denver’s Central Street Promenade project could potentially conflict with CDOT’s I-25 plans (and vice versa), the two governments agreed to merge their projects. Denver’s Central Street Promenade project is now part of CDOT’s I-25 project, and the whole effort is going to get underway in December 2011.

The combined project can now be described as including the following:

A 10-foot wide concrete bike/ped trail will be built along the southeast (I-25/Downtown) side of Central Street from 20th Street to 15th Street. Today, only weeds and a worn path in the dirt exist on that side of Central Street. The new sidewalk will provide a safe, convenient, and aesthetic link between 15th Street, the Highland Bridge at 16th Street, and 20th Street, the only three connections between Lower Highland and Downtown. In addition to the bike/ped path, new street lights/undergrounded utilities will be installed; more on-street parking (plus new parking restrictions) added along Central Street; new stop signs added on Central at 18th Street to slow traffic and enhance bike/ped crossings; and new street trees and landscaping installed along Central and at the 20th Street interchange.

The 15th Street bridge over I-25 will be completely rebuilt. The new bridge will have a wider span to allow for an additional traffic lane on I-25 below, as well as substantially wider sidewalks on the bridge itself (the existing bridge’s sidewalks are brutally inadequate). The new 15th Street bridge project also completes the gap between Platte and Central streets in the Better Denver Bond Program’s 15th Street reconstruction project.

The fences and lights on the new 15th Street bridge will also receive a nice upgrade. The CDOT default is chain-link fencing and no ped lights. But thanks to the efforts and perseverance of Councilwoman Judy Montero, her policy aide Nathan Batchelder, and the folks at Denver Public Works, upgraded fencing and ped lighting that matches the design of the 20th Street bridge will be installed instead. Montero and team are also working with Public Works and the various utility companies to find a way to underground all utilities on 15th between Platte and Boulder streets and ridding the streetscape of those ugly wooden poles and bulky overhead wires.

Meanwhile, CDOT had plans to someday fix the pinch-point created by the narrow span of the 15th Street bridge that requires southbound motorists entering the highway at 20th Street to merge left into traffic at the same point where motorists wanting to exit at Speer have to jockey for position and immediately veer to the right to exit after passing under 15th Street. With the bridge reconstruction, southbound I-25 will be widened between 20th and Speer to fit in a new auxiliary lane to eliminate the conflict between the merging and exiting traffic.

Here’s a GoogleEarth aerial where I’ve outlined the general project boundary area in yellow:

The $23 million project is scheduled for completion by late 2013. To keep tabs on the project and construction closures and delays, check out the CDOT project website here.