A tight, winding roadway where the accident rate is noticeably higher than the California average, State Route 299, specifically the stretch west of Redding, has for years worried the California Department of Transportation (Caltrans).
However, the completion of six curve realignment projects and several roadway pavement projects, dubbed the “Safer Roads: One Curve at a Time” projects, have eased those concerns by improving driver safety along SR 299.
Of the six SR 299 realignment projects, three projects occurred along an 8-mi. (12.8 km) stretch of roadway in Shasta County.
“Having three simultaneous earthwork projects within an eight-mile stretch of narrow-winding, two-lane road became a challenge for traffic handling,” said Chris Harvey, project manager of Caltrans District 2. “With three different contractors, the work along this corridor had the potential to severely affect traffic.”
However the contractors recognized the potential for delays and worked together when restricting traffic and conducting traffic control, said Tullis Inc.’s project manager Chris Brimhall.
Tullis Inc. served as the general contractor for the $2.4 million, Yankee Gulch project, which spanned .7 mi. (1.1 km) and replaced an existing 30 mph roadway curve with a new roadway alignment.
According to Brimhall, before any serious dirt was moved subcontractor Koala Ty Construction used 300 cu. yds. (229 cu m) of concrete to extend a box culvert and Tullis de-watered a nearby creek.
Following initial construction, all traffic was narrowed down to a single lane enabling Tullis to grind up a portion of the existing road using equipment such as a 330 excavator with a hydraulic hammer attachment.
The contractor used an onsite, mobile crushing and screening plant to recycle the grindings into base for the new portion of roadway.
In total around 8,000 tons (7,260 t) of base rock was used on the project, Brimhall said.
To construct the new roadway alignment, Tullis first placed a large amount of dirt and rock to create an embankment. Grading and paving of the new roadway section followed, which included the use of 5,000 tons (4,536 t) of hot mix asphalt.
The section of old roadway was then reclaimed and embankment was placed on it. Nearly 100,000 cu. yds. (76,460 cu m) of dirt and rock was used for all embankment work.
Completed in early October, the project also increased the Yankee Gulch clear recovery zone, an area adjacent to the road where errant vehicles can regain control if they’ve veered off the roadway.
Located further along SR 299 on a 5.5 percent grade stretch of two-lane highway, the Top of Buckhorn project posed challenges for Sierra Equipment Rental Inc. and Caltrans due to soil types, which caused an unexpected landslide.
“This area is comprised of decomposed granite that is subject to erosion,” Harvey said. “There are unpredictable hidden slip planes that are randomly oriented throughout the excavation.”
Because of the landslide, additional earthwork and the construction of a reinforced soil slope were required. This added work turned a single-season contract into a two-season contract.
Completed in October, the $3.8 million project had increased the design speed of a .6-mi. (.9 km) stretch of SR 299 to 50 mph by realigning the roadway’s curves. Shoulder widening work also occurred.
The third project located along the 8-mi. (12.8 km) stretch of SR 299, the $1.5 million Bottom of Buckhorn project was completed in June 2009.
Spanning .4 mi. (.6 km), the project increased the radius of a large roadway curve by adding a 7-ft. (2.1 m) paved left shoulder and ditch, and adding a 4-ft. (1.2 m) paved right shoulder, according to Caltrans District 2.
The improvements increased the large curve’s design speed from 23.8 mph to 35 mph.
Contractor J.F. Shea Construction Inc. also realigned five smaller surrounding curves as part of the project.
Aside from the Shasta County projects, three other curve improvement projects occurred along SR 299 in Trinity County.
The completed Sandhouse Passing Lane project involved the construction of a westbound, 12-ft. (7.6 m) wide passing lane, which enables cars to pass slower moving vehicles following the climb up Buckhorn Summit.
Started in June 2009, the $3.4 million China Slide project involved improving lane width and shoulder geometrics, changing a roadway curve, and increasing the clear recovery zone.
Also beginning in the summer of 2009, the Salyer Curve project took place along a portion of roadway where the accident rate is four times the statewide average for similar types of roadways, according to Caltrans.
The project included shoulder-widening work and cross slope corrections, and provided for legal Surface Transportation Assistance Act (STAA) truck wheel tracking.
The entire SR 299 corridor west of Redding is of special interest to Humboldt County, which partially funded the projects. The county is planning to develop a deep-water port and wants its large STAA trucks to utilize SR 299 for distribution purposes.
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