NEV 20 Omega Curves Project

Project Description

This project proposes to improve two non-contiguous segments of the alignment of State Route (SR) 20 in Nevada County between post miles (PM) 29.7-30.9 (White Cloud) and 36.8-39.8 (Lowell Hill) by modifying the existing horizontal and vertical curves of the roadway and adding turnouts. This project will update the roadway to current standards by increasing the curve radii, widening shoulders to 8 feet, adding turnouts for both directions, and improving the vertical profile grade. Additionally, the project will widen an existing turnout to standard width on SR-20 from PM 36.8 to 37.0.


The purpose of this project is to improve safety and reduce the number and severity of collisions by increasing the curve radii, widening shoulders, adding turnouts, improving the vertical profile, and improving the clear recovery zone.

These two sections of roadway experienced a total of 39 collisions in a recent 3-year period (January 1, 2015 to December 31, 2017), including 19 collisions involving injuries. The resulting total accident rate is higher than the statewide average for a similar type of facility. In addition, this section of the existing two-lane conventional highway facility has no room to pass. Slow-moving traffic has the potential to delay traffic flow leading to unsafe passing movements.


Map showing the location of the Omega Curves Safety Improvement Project on State Route 20 in Nevada County. Turnouts and left turn lanes will be added near Conservation Road and Washington Road. An additional turnout will be constructed near Burlington Ridge Road. Major roadway curve realignments are planned in the White Cloud and Lowell Hill areas.


This project is funded by the 2020 State Highway Operation and Protection Program (SHOPP) under the Operational Improvement program. 

Cost Estimate

Support Cost: $17,230,000
Capital Cost: $45,313,000
Total Project Cost: $62,543,000


Project Approval & Environmental Document: May 2020
Design Completed: April 2021
Advertise Project: July 2021
Begin Construction: October 2021
Complete Construction: December 2025

News / Events 

United States Forest Service

Caltrans has partnered with the United States Forest Service (USFS) to temporarily close trails impacted by project construction activities. USFS updates may be found using the below links.

Pioneer Trail Information

Recreation Report

Day Hiking Trails

Mountain Biking Trails

Press Releases:

10.06.2023 State Route 20 Now Open in Nevada County

10.03.2023 White Cloud Segment Closed Along State Route 20 in Nevada County

09.26.2023 State Route 20 Closed in Nevada County

09.22.2023 State Route 20 Temporary Closure Begins Next Week

09.15.2023 Public Meeting Planned for State Route 20 Temporary Closure

09.08.23 Full Closure of State Route 20 Scheduled for Omega Curves Project

07.20.23 Blasting Work Extends Traffic Controls on State Route 20

07.03.23 One-Way Traffic Control Extended on State Route 20

06.16.23 Traffic Impacts Continue Due to SR-20 Omega Curves Project

04.28.23 Work Scheduled to Resume for SR-20 Omega Curves Project

10.05.22 Extended Traffic Holds for Blasting Work Ahead on State Route 20

08.19.22 Occasional Saturday Work Scheduled for SR-20 Omega Curves Project

07.21.22 Major State Route 20 Improvements Continue in Nevada County

06.09.22 Construction Work and Travel Delays Continue on State Route 20

05.13.22 Continued Traffic Delays Ahead for State Route 20 Safety Project

04.27.22 One-Way Traffic Control Ahead on State Routes 20/193

03.30.22 One-Way Traffic Control Continues on State Route 20

03.01.22 Caltrans Beginning Vegetation Removal for  State Route 20 Safety Project

12.04.23 Work Continues Along State Route 20 in Nevada County

Project Contacts

Sam Vandell, Project Manager
(530) 741-4593

Jeremy Linder, Public Information Officer,
(530) 701-5209