SLO has wanted to build a new Highway 101 overpass for decades. What’s taking so long?
San Luis Obispo continues to inch along toward realizing its longstanding dream of a new highway overpass connecting the eastern and western parts of the city — but progress has been notably slow.
In 2023, the city picked its final design for the interchange that would span Highway 101 at Prado Road, estimating that construction could begin as soon as 2027.
Now, that estimate has been pushed back to late 2029, according to a schedule presented to the San Luis Obispo City Council on Feb. 18.
So what’s the holdup?
It’s just a very complicated project, according to a city engineer and project lead Wyatt Banker-Hix.
“One of the most challenging things is — we’ve got a great relationship with Caltrans, and we’re able to move things relatively quickly through their team — but they have a gigantic team who’s reviewing such a big project,” he told The Tribune.
Those team members have to get comments on design decisions, have them signed off by higher-ups, coordinate with project managers and then meet and disseminate all the info with all interested parties, he said.
There are also negotiations back and forth between the city’s project team and Caltrans, which has the ultimate authority for the project because it will take over maintenance once the overpass is built, Banker-Hix said.
“Those things definitely take a lot of time,” he said. “So that’s definitely a big one, because the size and complexity of the project.”
Additionally, the team has to coordinate with third-party groups to move certain utilities out of the way of the design and acquire the necessary right-of-ways, he added.
“Unfortunately, yeah, it’s a huge project, and it’s definitely taking some time,” Banker-Hix said.
Once completed, the $148 million interchange would add a signaled intersection just before the bridge overpass where Prado Road meets the northbound lanes of highway, with lights controlling the traffic for the ramps, overpass and Prado Road.
It will also act as a connection between Dalidio Road and the new San Luis Ranch neighborhoods and Prado Road.
Highway 101 overpass is decades in the making
According to a staff report, following Highway 101’s construction in the 1950s, the city considered adding an overpass at Prado Road as early as the 1970s.
Over the years, various efforts have been made toward realizing the goal, including in 1994 when the city added the topic to its General Plan. During the early development of what would eventually become the San Luis Ranch in the early 2000s, there was also significant conversation about the need for a connector between the new development and the western side of the city.
In the past decade, efforts to build an interchange have ramped up, with the city and Caltrans first entering into a cooperative agreement regarding the project in 2017.
Nearly two years ago, the city settled on its final design for the project — a major milestone toward it becoming a reality.
As of Tuesday, the project has also ballooned in costs.
When the design was picked in 2023, the estimated price tag for the project was roughly $97 million. Now, the total cost is estimated at $148 million, including all construction and design costs as well as administrative costs.
Since then, the project has been connected with several other major infrastructure changes in that area that would support the new overpass.
Those include the widening of an existing Prado Road bridge over San Luis Obispo Creek, which is in its final design phase with construction slated to begin in 2027, and still-early plans to eventually connect Prado Road to Broad Street.
When could construction start on Prado Road interchange?
During the Feb. 18 meeting, the City Council received an update on the longstanding project and approved some next steps in its development.
At one point, Banker-Hix cheekily noted that there are benefits to the lengthy development of the project.
“One of the advantages about waiting so long to construct an interchange is the benefits become more clear over time,” he said. “This is going to be an efficient cross-town link.”
According to the staff report, the project will next move into the plans, specifications and estimates phase, which includes awarding a design contract and numerous review steps.
That phase could last a total of 54 months, or roughly four and a half years, Banker-Hix said during the meeting.
That estimation was based on several factors “somewhat outside of our control” he said, like getting the necessary right of way approvals, relocating some utilities and lengthy review by the city and Caltrans.
“This will likely generate 400 or 500 (pages) at a time, so it’s going to take time for city and Caltrans staff to review those items,” he said.
If that phase is completed on schedule by summer 2029, construction on the overpass could begin by that fall.
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