Mark from Denver writes, “What’s driving you crazy? The exit from I-25N to 23rd Ave at the Aquarium is a disaster waiting to happen. It requires a gymnastic twist of head and body to watch eastbound 23rd traffic as well as watching for bicyclists in their lane. Last year Denver even failed to mow the weeds in the small island causing even more of a traffic hazard. Maybe your focus on this can get the city's attention.”
The weeds have been cut back and are pretty much dead at this point, but the awkward hard left look is still there Mark, but that could change in the next year as major changes have been proposed to alleviate this problem, including closing that ramp forever. That drastic move is one suggestion of a major project that would replace the bridges at 23rd Ave. as well as at Speer Boulevard over Interstate 25. Right now, the Colorado Department of Transportation is in the study phase as decision makers consider several options to replace the bridges and improve traffic flow on and above I-25.
The key to any changes to I-25 in central Denver are those two bridges. 23rd Ave. was built in 1952 and is rated as structurally deficient. The June 2022 structural evaluation listed that bridge as “somewhat better than minimum adequacy to tolerate being left in place as is” and received a clearance rating for I-25 traffic passing under it of “basically intolerable requiring high priority of corrective action."
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Both the 23rd Ave. and Speer bridges do not provide adequate vertical clearance over I-25 and have been hit multiple times by tall trucks, resulting in damage to the structure, exposing girders and primary reinforcing materials. Both bridges have special vertical height indicators that warn truckers to be in the center lanes on I-25 to prevent trailers from hitting the structures.
The twin Speer Boulevard bridges over I-25 were also constructed in 1952. The southbound span is listed as structurally deficient in the June 2022 inspection, while the northbound span is listed as fair. Both spans share the structural evaluation of “somewhat better than minimum adequacy to tolerate being left in place as is” and share the same poor clearance rating of “tolerable requiring high priority of replacement."
The options CDOT is considering, regarding how I-25 and the roads over the interstate between Colfax Ave. and I-25 will look, all depends on what design is chosen for the new Speer and 23rd Ave. bridges.
One alternative option would eliminate that access to 23rd from northbound I-25. As you well know Mark, 23rd Ave is one of the more popular bike crossings over I-25. Adrienne Razavi, organizing manager with the Denver Streets Partnership, said he is in favor of the option to close that ramp.
“With its high usage rates, removing the ramp is the best option to make central Denver safer for folks biking, walking, and rolling. While it seems like a no-brainer to us, removing a highway ramp never comes without opposition,” Razavi said.
Opposition for closing that access to 23rd Ave. comes from average drivers trying to get to downtown — residents around Diamond Hill as well as from the Children’s Museum and Downtown Denver Aquarium — the two major attractions with access directly off I-25 at 23rd Ave.
When I was out there, I saw frequent bicycle and scooter riders coming into close contact with the drivers making that turn off the ramp to go east on Water Street.
Daniel Fischer, the I-25 Speer & 23rd Bridge and Interchange Project Manager, said he has received over 1,300 comments and or emails — mostly regarding the idea to close the access from I-25 to 23rd Ave.
“There are strong opinions for those who oppose the alternative, primarily due to the direct access this interchange provides to a variety of destinations," Fischer said. "Simultaneously, there are strong opinions of those who support this alternative, primarily for its safety benefits for bikes and pedestrians across I-25, and for vehicles on I-25. Our team is reading each comment and sharing them with the technical team to be used alongside technical considerations and decision-making.”
Fischer said the project team has not finalized any decisions regarding the project's proposed alternatives. He said CDOT will continue to discuss alternatives with key stakeholders, community members and adjacent property owners to develop the best strategy to move forward.
The Denver North Star community paper reported in May of this year about the presentation CDOT gave to the Highlands community as the agency presented several bridge replacement options.
The paper reported the options for replacing the W 23rd Ave. bridge include:
- Braided weave: Creates a braid where traffic exiting northbound I-25 to Speer Boulevard goes underneath the on-ramp for 23rd Ave. traffic going north onto I-25. An additional traffic signal is added to the eastern side of the bridge.
- Close the interchange: Closing the ramp would eliminate the weave conflict between northbound 23rd Ave. traffic entering on I-25 and traffic exiting I-25 to Speer Boulevard. It would also allow Jefferson Park to be better connected to the Central Platte Valley for pedestrians, wheelchair users and people who bike and use scooters. Visitors to businesses such as the Children’s Museum, aquarium and REI would need to use the Speer Boulevard, 20th Ave. or 17th Ave. exits, adding three to four minutes of travel time.
- Bridge replacement only: This option replaces the bridge and adds a traffic signal on the eastern side of the intersection to eliminate the current free-flow traffic movements and increase safety on the eastern side of the bridge.
Speer Boulevard bridge replacement options include:
- Replacement only: Replacing the bridge, removing the current loop ramp exit on the northeast corner of the interchange and adding a stop light on the eastern end of the interchange.
- Single-point urban interchange: This option has a single traffic signal in the middle of the bridge where all the intersection’s left turns occur, with right turns in more traditional locations on either side of the bridge.
- Diamond interchange: A more traditional interchange with traffic signals on either side of the bridge and off-ramps in all directions.
- Partial cloverleaf interchange: Would add a cloverleaf ramp on the southwest corner of the intersection and remove the cloverleafs on the eastern side of the intersection, with traffic signals on either side of the bridge.
- Diverging diamond interchange: Similar to the interchange at U.S. 36 and McCaslin Boulevard in Superior, this design eliminates left-turn conflicts by having traffic cross over to the opposite side of the bridge (the left-hand side).
The paper added that CDOT also presented the “no-action alternative,” where current bridges would continue to be maintained as best they can.
The current listed work schedule has CDOT starting the preliminary design later this year or in early 2025. Then in 2026 and beyond, CDOT would identify the construction delivery method, identify construction funding and finish the preliminary design. Don’t expect any work to start until after that. The work would most likely take around three to four years to complete and be done in the early 2030s. You can find more info on CDOT’s I-25 Speer & 23rd Bridge & Interchange Project page here and you can sign up for the newsletter and project updates.
Denver7 Traffic Expert Jayson Luber says he has been covering Denver-metro traffic since Ben-Hur was driving a chariot. (We believe the actual number is over 25 years.) He's obsessed with letting viewers know what's happening on their drive and the best way to avoid the problems that spring up. Follow him on Facebook, Twitter or Instagram or listen to his award winning Driving You Crazy podcast on any podcast app including iTunes, iHeartRadio, Spotify, Podbean, or YouTube.
