Inside the C-470 Express Lanes Project Just Before Major Milestones

In the coming months, three of the largest Colorado highway construction efforts in recent memory are expected to get under way along the urban corridor: Central 70, I-25 North and I-25 South Gap. But another huge operation, the C-470 Express Lanes project, has been moving forward for months on 12.5 miles of roadway between Interstate 25 and Wadsworth Boulevard, and it's scheduled to reach some major milestones in the coming days.

From 10:30 p.m. on Friday, May 18, to 7 a.m. on May 19, eastbound C-470 will be closed from University Boulevard to Quebec Street to switch traffic onto new concrete lanes. And on both Sunday, May 20, and Monday, May 21, eastbound C-470 from Quebec to Interstate 25 will shut down from 10 p.m. to 5:30 a.m. the next morning to move traffic onto the Acres Green Bridge.

These changes, and the ones that preceded them, offer something of a preview for what commuters should expect from Central 70, I-25 North and I-25 South Gap. Included among them are intermittent closures of ancillary arterials, slower speeds, and lane shifts through narrow chutes that might remind drivers of bobsled courses in the Winter Olympics.

The C-470 Express Lane project began in August 2017 and will be complete next spring, says Colorado Department of Transportation communications manager Stacia Sellers.

The main addition to this stretch will be new express lanes in either direction. But they won't utilize the HOV-3 concept that charges tolls for drivers traveling alone or with one other person but allows parties of three or more to use them at no charge.

Instead, Sellers notes, "it’ll be just like the I-70 Mountain Express Lanes except it will be open full-time. There will be both a license plate toll or an Express Lanes tag toll. No free carpooling or motorcycles, just like the I-70 Mountain Express Lane."

At this point in the process, Sellers says, "we're reconstructing portions of the existing pavement. When you're driving, you'll notice over to the side that there's brand-new concrete. Once the traffic switch onto new pavement happens, we can start actually building the express lanes. But one of the most exciting accomplishments so far is that we're almost completely done with widening the existing bridges at University, Broadway and Yosemite. And we're close to finishing the South Platte River bridge. Once that's done, we plan to demolish the existing bridge. That should happen in the next month or so."

As is the case with bridgework on Central 70, I-25 North and I-25 South Gap, the changes being made reflect the likelihood of more lanes needed down the line.

According to Sellers, "Future expansion has been considered with the design of the bridges by widening to the median. In general, they can accommodate two express lanes and/or general purpose lanes in both the east and westbound direction. The Broadway, University, Big Dry Creek and Acres Green bridges eastbound, for example, will only have one express lane built with the current project. However, they were designed to allow for the addition of a second lane — likely an express lane — if needed, with no further widening required. As with the newly reconstructed Platte River Bridges, they will provide the median width to allow for inside widening to accommodate a future additional lane, if needed."

Over recent months, drivers have been taking a serpentine route through this portion of C-470, with speeds lowered to 55 miles per hour, smaller-than-usual shoulders and routes that take drivers over rumble strips — the roughened patches of asphalt designed to alert motorists who have drifted out of their lane. "It can be a little bit of a bumpy ride," Sellers acknowledges. "But with the newly paved general service lanes that we'll be opening, people will have a much smoother ride and a smoother C-470 as a result."

As for the lower speed limits, Sellers says, "Most people go faster than that, unfortunately. That's unsafe. It's safer to go at the posted speed."

On the other hand, slowdowns haven't been so severe that they've cause a large percentage of drivers to abandon C-470 entirely. "We're not hearing issues of people going off of it," Sellers notes. "But they might be going to I-25 or a different highway."

A number of full closures of C-470 have taken place over the course of the project to date, but like the ones scheduled for May 18 through May 21, they've largely happened at night. "That's a little more convenient for the traveling public and a lot safer for our workers out on the road," Sellers points out. "We did have to close off the University Boulevard ramp during the day in February. Basically, we had people turning once they got to the stoplight to turn onto the ramp, so they didn't have a merge or auxiliary lane. So it wasn't that big of a closure — but it was one of our larger ones."

Another closure is ongoing: Willow Creek Trail has been closed 24 hours a day since late March and isn't slated to reopen until May 28, necessitating a detour of about one mile. That seems like a formula for unhappiness, but in general, Sellers says, CDOT has received fewer complaints than expected. "When the University Boulevard ramp was closed, I would have thought we'd have gotten a lot of calls, but we really didn't. And the public seems keen about the express lanes. We did extensive outreach with the public, and I think a lot of people are excited about it."

She says it's too early to tell if the express lanes on C-470 will get more use than E-470, which is tolled in its entirety — "but we do see thousands of motorists using our other express lanes each day, and we expect C-470 to have similar success as seen in our other lanes."

In the meantime, Sellers encourages motorists who'll be living with C-470 construction for another year "to drive slower in our work zones, and please be conscientious of trucks pulling in and out of those areas. Our truckers know the appropriate times to turn, and they give plenty of notice before going over into traffic. So it's important to be aware and vigilant as you're driving through the construction zones."

Click to access the Colorado Department of Transportation's C-470 Express Lanes project page.