New Hwy. 101 project in SLO County a ‘breakthrough in bridge construction’
AI-generated summary reviewed by our newsroom.
- Caltrans used ClearCast to build a bridge at deadly Wellsona Road intersection.
- ClearCast enables faster inspections and reduces construction lane closures.
- Project marks pilot use of ClearCast in California; future adoption under review.
As construction continues on a project to improve one of San Luis Obispo County’s most dangerous intersections, Caltrans crews are using an innovative, see-through tool to complete roadwork just north of Paso Robles.
The California Department of Transportation said it's using a transparent deck form, known as ClearCast, to create a bridge near the intersection of Highway 101 and Wellsona Road.
It’s the first time in history that the transparent deck form is being used in California, the road agency said in a social media post.
“Clear-Cast made its debut with Caltrans and all of California with this bridge deck technology,” the agency said. “The use of these ClearCast transparent forms results in accelerated construction and more efficient work.”
Caltrans is constructing a new 112-foot underpass beneath Highway 101, as well as a frontage road connecting the underpass with Wellsona Road on both sides of the highway.
Previously, eight people died in vehicle crashes at the intersection between 2014 and 2024, making the site the second-deadliest crossroad in the county in terms of the number of traffic fatalities over the past decade, the Tribune previously reported.
Here’s why crews are integrating new transparent technology into the improvement project.
What is ClearCast?
The transparent, stay-in-place bridge deck system is a “breakthrough in bridge building,” Contech Engineered Solutions, the makers of ClearCast, said on its website.
In effect, the clear deck form — which is less than a quarter-inch thick — “allows concrete to be inspected from below during the initial pour and allows for routine inspections over the life of the bridge,” Caltrans said.
The clear deck form helps hold fluid concrete in place while it hardens, according to Caltrans.
The ClearCast system requires no structural support and is not weight-bearing.
In the past, crews have relied on removable corrugated metal or wood forms as molds for concrete, but these methods make it difficult to inspect and confirm the quality of concrete pours, according to the state road agency.
Caltrans said the tool will not only improve inspections and on-site safety but also speed up long-term roadwork.
“It accelerates construction and allows more efficient work and being able to move on to other projects quicker,” Caltrans’ engineering team wrote in an email. “It helps the public with reduced lane closures for less hours of the day.”
Crews working on the project at the Highway 101 and Wellsona Road intersection installed the first clear deck bridge form on July 1, according to Caltrans.
Will new tool be used in other Caltrans projects?
Caltrans said it doesn’t know whether ClearCast will continue to be used for future state construction projects.
The transparent deck form at the intersection of Highway 101 and Wellsona Road is a pilot project, Caltrans told The Tribune.
“Once the project is complete, evaluations are likely to determine future use,” the state road agency said.
This story was originally published August 25, 2025 at 3:06 PM.
