Douglas County begins its largest transportation construction project to date Wednesday with the widening of South Santa Fe Drive (U.S. 85) at C-470 from four to six lanes.

It will close eastbound C-470 access from South Santa Fe Drive through 2023, but the flyover to eastbound lanes will remain open. Drivers going southbound on Santa Fe can also take County Line Road east to Lucent Boulevard south to access east-bound C-470.  

Construction is expected to last until 2025. 

Travelers should expect overnight lane closures on C-470 there between 9 p.m. and 5 a.m., and daytime lane closures on Santa Fe Drive during non-peak hours. Overnight lane closures on U.S. 85 will occur between 7 p.m. and 5:30 a.m.

Other improvements to traffic flow will include southbound U.S. 85 to eastbound Town Center Drive; southbound Santa Fe Drive to eastbound Highlands Ranch Parkway and northbound Santa Fe to westbound C-470. 

A new shared-use bike path will come to the east side of Santa Fe and road crossing improvement are on tap for the Highland Canal and C-470 Trails. Plans include area bus stop improvements.  

Residents can sign up for news updates  through Douglas County’s website. Further information can be found at the project website. 

The project is a collaboration between Douglas County, the Colorado Department of Transportation, the Denver Regional Council of Governments, Federal Highway Administration, Highlands Ranch Metro District, Sterling Ranch and Solstice Developers, according to the Douglas County website.