To: Honorable Mayor and Members of City Council
From: Jessica Lowe, Public Works Director
Prepared By: Lorien Clark, Senior Transportation Planner
TITLE:
Title
Annual Update to Speed Limits on City Streets
LABEL
RECOMMENDED ACTION:
Recommendation
(1) Approve the first reading and introduction of an ordinance amending Napa Municipal Code Section 10.20.040 related to the establishment and enforcement of speed limits.
(2) Adopt a resolution determining that a Declared Speed Limit is justified based on an Engineering and Traffic Survey for identified City streets and roadway segments and determining that the actions authorized by this resolution are exempt from CEQA.
Body
DISCUSSION:
This report summarizes the requirements for setting speed limits, describes the process for completing the Engineering and Traffic Surveys in full compliance with the requirements, and recommends City Council action to amend the Napa Municipal Code section related to the establishment and enforcement of speed limits.
Approval of the proposed ordinance and resolution will result in the lowering of the speed limit on 33 roadway segments by 5 mph and maintaining the speed limit along 19 roadway segments. The approval also documents the sufficiency of the required Engineering and Traffic Surveys in complying with all requirements of State laws and the standards established by the California Department of Transportation to support enforcement.
The City of Napa Public Works Department is responsible for performing and maintaining current Engineering and Traffic Surveys for the purpose of establishing declared speed limits on many City roadways. According to the 2026 California Manual of Uniform Traffic Control Devices (CA MUTCD), “The setting of speed limits can be controversial and requires a rational and defensible determination to maintain public confidence. Speed limits are normally set near the 85th percentile speed that statistically represents one standard deviation above the average speed and establishes the upper limit of what is considered reasonable and prudent. As with most laws, speed limits need to depend on the voluntary compliance of the greater majority of motorists. Speed limits cannot be set arbitrarily low, as this would create violators of the majority of drivers and would not command the respect of the public.”
The California Vehicle Code (CVC) establishes several speed laws including: the basic speed law, two maximum speed limits, and several prima facie speed limits. The Latin term “prima facie” means “at first sight” and by extension when used to describe a speed would be “upon initial observation the apparent, reasonable and prudent speed”. As an example, when driving along a residential roadway with no posted speed limit, the prima facie speed limit is 25mph. The law does not require posting these prima facie limits, which are considered readily apparent. State law permits local authorities to declare speed limits that differ from maximum and statutory prima facie limits if adopted on the basis of Engineering and Traffic Surveys. These are known as Declared Speed Limits and must be posted for speed enforcement.
Engineering and Traffic Surveys, as defined by the California Vehicle Code (CVC), must be implemented properly to document the normally careful and competent actions of responsible drivers. Engineering and Traffic Surveys shall include a consideration of prevailing speeds, collision history, and roadway conditions not readily apparent to the driver. Engineering and Traffic Surveys are, at their core, a measurement of prevailing speed or the speeds of reasonable and prudent drivers in action. Proper and consistent use of equipment, location selection, time of day selection, and trained personnel are key to collecting prevailing speeds. Not all driver speeds are collected within the random sample of reasonable and prudent drivers under normal conditions. For example, drivers behind slow moving trucks and buses, or drivers who unreasonably start quickly at traffic signals or stop signs are not collected.
From the collected prevailing speeds, an 85th percentile speed is calculated. The 85th percentile speed is the speed at or below which 85% of drivers are traveling on the particular segment of roadway. The 85th percentile speed is then rounded to the nearest 5mph increment which establishes a recommended speed limit. A 5mph reduction to the recommended speed can be applied if justification is documented by the registered Civil or Traffic Engineer approving the Engineering and Traffic Surveys. Assembly Bill No. 43 (AB43), allows an additional 5mph reduction to be applied if the roadway segment meets the definition of a “safety corridor” or “land or facility that generates high concentrations of bicyclists or pedestrians” established by the CVC and CA MUTCD. The total reduction from the 85th percentile speed shall not exceed 12.4mph.
Since the last presentation to Council on speed limits, Assembly Bill No. 382 (AB382) was enacted. Effective January 1, 2031, the bill lowers the prima facie speed limit in school zones from 25 MPH to 20 MPH when children are present. Staff is currently reviewing implementation requirements; no changes to school zone speed limits are proposed as part of the recommended action.
Engineering and Traffic Surveys are valid for 5, 7, and 14-year periods depending on changing conditions and evaluation by a registered Civil or Traffic Engineer. Sometimes an updated Engineering and Traffic Survey can increase or decrease the posted speed limit along a roadway segment. Before a posted speed limit is changed on a roadway and becomes enforceable, the Engineering and Traffic Surveys must be adopted by City Council and amended into the Municipal Code. Enforcement of posted speed limits that are not based on State Laws or City Codes becomes difficult to justify in court and leads to speeding citations being overturned.
Of the 52 Engineering and Traffic Surveys included in this annual update:
• 19 segments have no changes; and
• 33 segments are being lowered by an increment of 5mph.
The specific changes are as follows:
|
Street or Roadway Segment Revised |
Declared Speed Limit (mph) |
|
Beard Road - Pueblo Avenue to Trancas Street |
25 |
|
Browns Valley Road - Partrick Road (west) to Redwood Road |
30 |
|
Buhman Avenue - City Limit (south) to Crestview Way |
35 |
|
Buhman Avenue - Crestview Way to Browns Valley Road |
25 |
|
California Boulevard - Lincoln Avenue to Pueblo Avenue |
30 |
|
California Boulevard - Pueblo Avenue to Trancas Street |
30 |
|
Coombsville Road - Terrace Drive to City Limit (east) |
30 |
|
First Street - California Boulevard to Jefferson Street |
25 |
|
Freeway Drive - Old Sonoma Road to Laurel Street |
30 |
|
Freeway Drive - Laurel Street to First Street |
30 |
|
Imola Avenue - Shurtleff Avenue to east City Limit |
30 |
|
Kaiser Road - City Limit (west) to State Route 221 |
35 |
|
Lincoln Avenue - Soscol Avenue to Silverado Trail |
30 |
|
Linda Vista Avenue - Redwood Road to Trower Avenue |
25 |
|
McKinstry Street - First Street to Soscol Avenue |
25 |
|
Napa Valley Corporate Drive - City Limit (south) to NV Corporate Way |
35 |
|
Old Sonoma Road - Foster Road to Jefferson Street |
25 |
|
Partrick Road - Browns Valley Road (west) to Browns Valley Road (east) |
30 |
|
Redwood Road - Dry Creek Road to Solano Avenue |
30 |
|
Salvador Avenue - State Route 29 to City Limit (east) |
25 |
|
Second Street - California Boulevard to Jefferson Street |
25 |
|
Shetler Avenue - Soscol Avenue to Parrish Road |
25 |
|
Solano Avenue - Trower Avenue to Salvador Avenue |
35 |
|
Soscol Avenue - Lincoln Avenue to Pueblo Avenue |
35 |
|
Soscol Avenue - Pueblo Avenue to Trancas Street |
35 |
|
South Coombs Street - Imola Avenue to Spruce Street |
25 |
|
Third Street - California Boulevard to Jefferson Street |
25 |
|
Third Street - Soscol Avenue to Silverado Trail |
25 |
|
Trancas Street - Big Ranch Road to City Limit (east) |
30 |
|
Trower Avenue - Dry Creek Road to Linda Vista Avenue |
30 |
|
Trower Avenue - State Route 29 to Jefferson Street |
25 |
|
West Lincoln Avenue - Lone Oak Avenue to Solano Avenue |
25 |
|
West Pueblo Avenue - Linda Vista Avenue to Solano Avenue |
25 |
The City annually updates the Napa Municipal Code for Speed Limits to maintain speed limits that comply with CVC requirements and are enforceable by Police and upheld in the Courts.
The proposed Ordinance will go into effect 30 days after its final adoption. This will ensure that the City of Napa can enforce speed regulations to ensure safe operation of vehicles on city roadways related to the proposed amendments. If the proposed Ordinance is not approved, the City would not be able to enforce posted speed limits by use of radar or other electronic devices.
FINANCIAL IMPACTS:
There is no General Fund impact associated with the adoption of the proposed Ordinance. Costs related to updating and installing revised speed limit signs is incorporated into the Public Works Department’s current Operating Budget.
CEQA:
City staff recommends that the City Council determine that the Recommended Action is exempt from CEQA pursuant to CEQA Guidelines Section 15301 (minor alteration of existing streets and sidewalks).
DOCUMENTS ATTACHED:
ATCH 1 - Ordinance
ATCH 2 - Resolution
EX A - Engineering and Traffic Surveys
NOTIFICATION:
Legal notice of public hearing published in the Napa Valley Register on May 7, 2026.