Highway 99 improvement work in Modesto expected to cause traffic delays through year
Beginning Monday, drivers on Highway 99 through Modesto should expect congestion and delays as Caltrans begins a months-long project to add acceleration and deceleration lanes, among other work.
The $13.8 million project, to be performed by Teichert Construction of Sacramento, will stretch from South Ninth Street to the Pelandale Avenue interchange, according to a post on the Caltrans District 10 Facebook page.
Typically, night work will be Sunday through Thursday from 8 p.m. to 6 a.m., while day work will be Monday through Friday from 7 a.m. to 5 p.m. Drivers should allow for an extra 15 minutes of travel time depending on the time of day and the work being performed, Caltrans advises. The project is expected to finish in December.
Caltrans identified six locations on Highway 99 in Modesto with a history of sideswipe and rear-end collisions where vehicles are coming onto and exiting the highway, District 10 spokesman Rick Estrada told The Bee in an email.
The scheduled work at the six locations is as follows:
- A 1,500-foot deceleration lane at the northbound 99/Briggsmore Avenue off-ramp
- A 1,200-foot acceleration lane at the northbound 99/Briggsmore Avenue on-ramp
- A 700-foot deceleration lane at the northbound 99/Standiford Avenue off-ramp
- A 1,200-foot acceleration lane at the northbound 99/Beckwith Road on-ramp
- An auxiliary lane on northbound 99, extending from the Standiford Avenue on-ramp to the adjacent Pelandale Avenue off-ramp
- An auxiliary lane on southbound 99, extending from the Pelandale Avenue on-ramp to the adjacent Standiford Avenue off-ramp.
Auxiliary lanes allow vehicles to travel between interchanges without merging onto the freeway.
The conceptual report for the project — to accommodate increasing traffic flow on the stretch of highway — was approved in February 2010.
The improvements are critical because of Highway 99’s significance as a corridor for commuters, big rigs, commercial vehicles and other travelers, the Caltrans Facebook post says. In Modesto, well over 145,000 vehicles travel 99 in an average day, including 21,750 big rigs and commercial trucks, Estrada said.
That compares, he said, to these past figures:
- In 2007, average daily traffic was about 124,000 vehicles, including 14,900 large trucks.
- In 2013, it was about 133,000 vehicles, including 17,300 large trucks.
“During peak hours, State Route 99 suffers from congestion related to on-ramp and off-ramp traffic volumes,” Estrada said. “Vehicles entering the highway can struggle due to short acceleration lanes, making it difficult for vehicles to hit highway speeds as they merge. Vehicles exiting the highway can experience off-ramps where vehicles are backed up to the mainline, forcing vehicles to slow while still on the mainline or switch lanes to avoid these stationary vehicles.”
A noise study was conducted for the project, which concluded it would have a noise impact on northbound 99 just south of Standiford Avenue. Caltrans will build a mason-block sound wall just north of Heritage Ford, from Whitcomb Way to Brenner Way. It’s scheduled to be completed during the summer.
This story was originally published February 26, 2019 at 11:29 AM.
