Public WorksRoads




Welcome to the Napa County Roads Division. We are committed to maintaining and preserving the Napa County road system so that it is safe, reliable and accessible for all users.
The Roads division is responsible for maintaining approximately 450 miles of public roads, 79 bridges and 50 major drainage structures within the unincorporated area of the County. The division is active in other road-related safety efforts such as vegetation management and maintenance of structure, drainage facilities, guardrails, traffic signs, signals and pavement markings.
We invite you to visit our links page for useful road and safety links.


Special Events on County Roads

More information about these events, which include marathons, bicycling events, triathlons and more -- including application information and how to submit concerns to County staff.


Major Road Construction in Napa County 2017-2020 


New Development - Traffic Impacts


Traffic Engineering Links

Requirements for preparation of traffic impact studies

Evaluation of cumulative impacts

Left Turn Lane Warrant Graph
Napa County Traffic Counts


Traffic Mitigation Fees -- Napa Valley Business Park

All new development, or improvements to existing development that will generate additional traffic, in the Napa Valley Business Park (area surrounding Napa County Airport) are subject to a Traffic Mitigation Fee


Call Before You Dig

Before beginning any digging authorized by this permit, you must call Underground Services Alert (USA) at 1-800-227-2600 for buried utilities. In addition, applicants and contractors are required to contact our Inspector in advance of construction and review the USA requirements; the inspector confirms USA has been contacted.