Following more than three years of construction, Douglas County officials on Wednesday introduced a new underpass shortcutting bikers and pedestrians under one of metro Denver’s busiest roads.

The new $4.5 million underpass, connects the C-470 Trail and High Line Canal Trail beneath Santa Fe Drive, paving a long-desired shortcut for bikers and pedestrians. Recreationalists have lamented the dangers of having to once cross the busy road.

Construction began on the underpass in October 2022 and finished this past week. Douglas County paid for roughly 70% for its underpass, while the Denver Regional Council of Governments Transportation Improvement Program contributed the rest, according to a county spokesperson.

Douglas County officials said the underpass, interconnecting Highlands Ranch Metro District neighborhoods and Chatfield State Park, offers a safer route under U.S. Highway 85 directly south of C-470.

“Our ultimate goal is to improve safety along the entire C-470 corridor and trail by removing all crossings and signalized intersections,” Commissioner Kevin Van Winkle said, celebrating the opening on Wednesday.

“The trail is a key transportation link that serves a larger cycling community along one of the most traveled trails to form Chatfield and South Platte, which connects Denver and the mountain trails,” said Van Winkle, who represents the northwest portion of Douglas County.

Santa Fe acts as the alternative thoroughfare between Castle Rock and Denver. Douglas County transportation officials earmarked the C-470 trail underpass as part of the US 85 widening project. As of Wednesday, the third and final new “continuous flow intersection” opened along the corridor between C-470 and Highlands Ranch Parkway.

Steve Coffin, board member from the High Line Canal Conservancy group, called the C-470 trail underpass’ completion a “major milestone,” noting it addresses the last remaining underpass gap along the 71-mile trail system.

“Not only is Douglas County a vital partner of the High Line, it’s also home to more than 25% of our 71 mile trail,” Coffin said. “It includes some of the most amazing, scenic, beautiful trails.”

Commissioner George Teal said the new underpass and US 85 widening will economically benefit the county.

“By improving safety and widening the corridor, we are delivering an economic stimulant,” Teal said, promising that “businesses can thrive.”

During Wednesday’s ribbon cutting, several bikers stopped by the new underpass, curious as to what their new-look bike route entails.

“To me, this just opens up more avenues, because I live so close,” Marilyn Binkley, who bikes almost every day in the area, said. “For several years, I couldn’t go to get on the Gary Carter Greenway trail or get into Chatfield.”

“We used to have to cross on top, and that was scary,” Binkley said. “This is safer … the fact that you don’t have to worry about cars makes a huge difference.”