At the intersection with Fountain Boulevard, the route then runs concurrent with US 24 until reaching a partial cloverleaf interchange at Platte Avenue, where US 24 splits from SH 21 and heads east.

In 1964, the City of Colorado Springs included the "Powers Corridor" in its major thoroughfare plan as a bypass of the city two miles east of Academy Boulevard,[2][3]: 2–3  and, in the 1970s, Colorado Springs and El Paso County recommended that Powers Boulevard be constructed "at least to expressway standards" and proposed it to be included in the Interstate Highway System.

[3]: 2–2  The Powers corridor was included in the National Highway System,[7]: 1  and studies were prepared to extend the road to I-25 north and south of Colorado Springs.

[3]: 2–3  In June 1999, the City of Colorado Springs, El Paso County, and CDOT completed an agreement for a phased transfer of ownership for Powers Boulevard.

According to the plan, over the following years, CDOT would assume ownership of Powers Boulevard with the intent to develop it as a limited-access freeway, and, in exchange, the city would assume ownership of several CDOT-owned roads, including the I-25 Business Loop along Nevada Avenue and SH 83 north of US 24; at this time, Powers Boulevard was planned to be the new path of SH 83 through Colorado Springs.

[8] In March 2000, the Colorado Transportation Commission adopted a resolution designating the future Powers Boulevard between I-25 and Woodmen Road as a freeway.

[2][10] In late 2019, CDOT finished designs for a diverging diamond interchange between SH 21 and Research Parkway in northern Colorado Springs.

[24] Preliminary plans were developed to construct an interchange at Research Parkway, the last at-grade intersection between Dublin Boulevard and the northern terminus of Powers, but they were put on hold in late 2018 after voters rejected two ballot measures proposing funding for state transportation projects.

[30] Construction of the northern extension of SH 21 to I-25 is underway, led by the Copper Ridge Metropolitan District; the project includes the segment from I-25 to Voyager Parkway.

The 2010 central Powers Boulevard studies proposed the interchange between SH 21 and Airport Road/Stewart Avenue as a priority project due to congestion at the intersection and its use as the main entrance to Peterson Air Force Base.

[33] In 2014, CDOT identified a diverging diamond as the preferred interchange type,[34] and, in 2020, they included the project in their ten-year vision plan, anticipated for the second half of the decade.