California Safe Speeds Toolkit: Current Speed-Limit-Setting Law

Current Speed-Limit-Setting Law

In this part of the Toolkit, the various flexibilities related to speed limit setting in California are discussed in greater detail. Most, but not all, of these flexibilities relate to AB 43 or AB 1938. It is important to note that each method described below has some specific requirements or features that jurisdictions need to pay attention to for implementation; accordingly the requirements or features associated with each method are described using the following definitions: 

E&TS needed for radar enforcement: If jurisdictions wish to enforce using radar, an E&TS must be conducted and updated regularly (see CVC § 627 and CVC § 40802). 

Exempt from certain speed trap provisions: Most roadways in California require an E&TS to justify radar enforcement (see above). If no valid E&TS exists and enforcement is pursued, this is considered a “speed trap” (which is not legal in California). However, some roadway types do not require an E&TS for radar enforcement - these roadways are therefore exempt from this requirement of the speed trap provisions (see CVC § 40802). 

No signage required: On local roads and in certain prima facie zones (i.e., business districts, railroad crossings with an obstructed view, uncontrolled intersections with an obstructed view, and alleys), the prima facie speed limits apply even in the absence of actual speed limit signage.

Signage required: In other prima facie zones (i.e., business districts and school, senior, and playground zones), prima facie speed limits apply only when speed limit signage is present

Ordinance/resolution required: While some flexibilities in speed limit setting can simply be accomplished with no action from local government, many other flexibilities can only be undertaken after a local governing body (e.g. city council or county board of supervisors) has voted on and passed an ordinance or resolution to allow speed limit changes to take place on a specific corridor. 

AB 43 changes: When proposals for speed limit changes are presented to elected officials, it is helpful to clarify in the rationale whether the requested flexibility is linked to AB 43.  

1. Prima Facie Speed Limit Setting Options for Common Context-Sensitive Zones

The California Vehicle Code (CVC) designates prima facie speed limits to govern vehicular speeds on roads that may not have speed limits. A prima facie speed limit is a default speed limit that applies under conditions when a posted speed limit is not determined based on an engineering and traffic survey. Several types of prima facie speed limits and the areas they apply to respectively are described below, with notation when this zone has received updated treatment under AB 43. Note that some prima facie zones require an E&TS for radar enforceability and some do not. 

1. 25 mph prima facie zones:  The following areas may have a prima facie speed limit of 25 mph (one zone can go as low as 20 mph).  

A. Residential District

If the density of buildings fronting the street is higher than a certain threshold, a street may be classified as a residential district. The ratio is 13+ houses or structures on one side, or 16+ houses or structures on both sides for every 0.25 miles of roadway. Refer to CVC § 22352(b) regarding prima facie zones for residential districts and to CVC § 515 for the specific definitions of residence districts. 

(No signage required, E&TS needed for radar enforcement)

—> Leads to Local Road Definition under Speed Trap Provisions

Local roads are exempt from certain speed trap provisions and may be radar enforceable without an E&TS. Roads can be classified as “local” under the “California Road Systems Map” or if they meet certain conditions that most narrower two-lane residential roadways would meet. Refer to CVC § 40802 for the specific definitions of local roads for speed trap definitions.  

(No signage required, Exempt from certain speed trap provisions)

B. Business District 

If more than half of the property fronting a road is being used for business, the road may be classified as a business district. The minimum distance is 300 ft if properties on only one side of the road are counted, and 600 ft if properties on both sides of the road are counted. Refer to CVC § 22352(b) regarding prima facie zones for business districts and to CVC § 235 and CVC § 240 for the specific definitions of business districts.

(No signage required, E&TS needed for radar enforcement)

—> Leads to Local Road Definition under Speed Trap Provisions

Local roads are exempt from certain speed trap provisions and may be radar enforceable without an E&TS. Roads can be classified as “local” under the “California Road Systems Map” or if they meet other specific conditions. Refer to CVC § 40802 for the specific definitions of local roads for speed trap definitions.  

(No signage required , Exempt from certain speed trap provisions)

C. Business Activity District (20 mph, 25 mph)

Newly created under AB 43, business activity districts can be established in commercial areas such as downtowns and neighborhood business corridors if the land use and roadway meet certain conditions. Roads in business activity districts may have a prima facie speed limit of 20 or 25 mph. Proceed to Part 4 of this toolkit for more details. Refer to CVC § 22358.9 for the specific definitions of business activity districts.  

(Signage required, Exempt from certain speed trap provisions, Ordinance/resolution required, AB 43 changes)

D. Senior Zone 

If the road passes a senior center or other facility primarily used by senior citizens, a Senior Zone may be established. This only pertains to local roadways. Refer to CVC § 22352(b) regarding prima facie descriptions of senior zones.

(Signage required, Exempt from certain speed trap provisions)

  1. Time-specific prima facie zones: These areas may have a prima facie speed limit of 25 or 15 mph, but only apply when children are present. Please refer to CVC § 22352(b), § 22358.4 and § 22357.1

A. School Zone 

A time-restricted school zone speed limit of 25 mph can be established on roadways adjacent to schools in the vicinity near school grounds. Refer to CVC § 22352(b) for specific definitions and requirements. 

(Signage required, Exempt from certain speed trap provisions)

—> Leads to AB 321: 15 mph school zones

AB 321 (2008) allows jurisdictions to establish time-restricted 15 mph school zones up to 500 ft from school grounds and 25 mph school zones from 500 ft to 1000 ft from school grounds. The 15 mph school zone and extended 25 mph school zone may only be established in residential districts for two lane roads with a posted speed limit of 30 mph or less. Proceed to Part 3 of this toolkit for more details. Refer to CVC § 22358.4 for specific definitions and requirements. 

(Signage required, Exempt from certain speed trap provisions , Ordinance/resolution required)

B. Children’s playground 

A time-restricted 25 mph prima facie speed limit may be established on roadways, with the exception of state highways, adjacent to any children's playground in a public park. Refer to CVC § 22357.1

(Signage required , Ordinance/resolution required)

3. 15 mph prima facie zones 

A prima facie speed limit of 15 mph applies to the following specific circumstances. Please refer to CVC § 22352(a)

A. Railroad crossing with obstructed view 

(No signage required , Exempt from certain speed trap provisions)

B. Uncontrolled intersection with obstructed view 

(No signage required , Exempt from certain speed trap provisions)

Image of a car at an intersection. The view of the driver is obstructed by bushes.

C. Alley

Roads serving rear or side entrances with a width at or under 25 ft. Refer to CVC §22352(a) and CVC §110 for specific definitions and requirements. 

(No signage required , Exempt from certain speed trap provisions)

Image of an alley with pedestrians walking by.

A summary of the type of zones and their respective prima facie speeds are provided in Table 1 below.

Table 1: Prima Facie Speed Limit by Locally-Controlled Road Context

Locally-controlled road contextPrima facie speed limitExceptions allowed?E&TS required for radar enforcement?
Residential District25 mphNoYes, unless a road is deemed a “local road
Business District25 mphNoYes, unless a road is deemed a “local road
Business Activity District20 mphNoNo
Senior Zone25 mphNoNo
School Zone25 mphYes, AB 321 allows for 15 mph speed limits under certain conditionsNo
Children’s playground25 mphNoNo
Railroad crossing with obstructed view15 mphNoNo
Uncontrolled intersection with obstructed view15 mphNoNo
Alley15 mphNoNo

2. Opportunities to Utilize Recent State Legislative Changes in Safe Speed Limit Setting (AB 43 & AB 1938)

While new legislation has increased flexibility to set safe speeds on local roads, local jurisdictions will need to carefully research these new allowances to identify opportunities for speed reduction. The provisions of AB 43 and AB 1938 identify specific criteria for speed reductions based on road classification, land use, and other designation such as prima facie zones. Local jurisdictions may elect to systematically identify and implement reduced speed zones or collect the requisite data on a case-by-case basis. 

Together, AB 43 (2021) and AB 1938 (2022) give local jurisdictions the ability to further lower speed limits on locally-controlled roads and include additional provisions affecting E&TS procedures and radar enforceability (California State Legislature 2021; California State Legislature 2022). The table below summarizes some of the recent changes, but see sections 4, 5, 6, 7, and 8 for more details:

Table 2: Key Changes in Speed Limit Setting Practices resulting from AB 43 and AB 1938

Applicable to locally- controlled roads Applicable to state- controlled roads
Requires an Engineering & Traffic Survey? * 
Effective status
1
Establishing prima facie speed limit for a Business Activity District
Yes No No In effect
2
Designating road as Safety Corridor (High Injury Network) to lower speed limit
Yes No Yes On or after June 30, 2024
3 Designating road as High Pedestrian and Bicycle Activity Area to lower speed limit Yes No Yes On or after June 30, 2024
4 Retain Current or Restore Immediately Prior Speed Limits if E&TS speed is higher than reasonable or safe and no general purpose lanes have been added Yes No Yes In effect
5 Extending the E&TS validity period based on judgment of registered engineer Yes Yes No In effect
6 Round speed limit down to the nearest  5 mph instead of rounding up Yes Yes Yes In effect
7 Declare a 15 or 20 mph speed limit if justified by the E&TS Yes Yes Yes In effect

*Even if “No,” it is still recommended for the reviewing agency to include the affected roadways in their report to the court concerning speed limit changes and provide justification for the speed limit zone implementation

3. 15 mph and Extended 25 mph School Zones 

Local jurisdictions can establish 15 mph school zone speed limits and extended 25 mph school zone speed limits on certain roadways adjacent to school grounds. Refer to CVC § 22358.4 for specific definitions and requirements. While currently only allowable on local roads, a pending ordinance may extend these allowances to the state highway system, if approved by the California Department of Transportation.

  • 15 mph school zone prima facie speed limit can be established:

    • Up to 500 ft from school grounds.

    •  In a residential district (refer to CVC § 240).

    • On a road with two or fewer travel lanes. 
    • On a road with a maximum posted speed limit of 30 mph before and after the school zone. Note: it may be possible to reduce surrounding 35 mph zones to 30 mph using other criteria to allow for this option. 

(Signage required, Exempt from certain speed trap provisions, Ordinance/resolution required)

  • Extended 25 mph school zone prima facie speed limit can be established:
    • 500 ft to 1000 ft from school grounds. 

    • In a residential district (refer to CVC § 240). 

    • On a road with two or fewer travel lanes. 

    • On a road with a maximum posted speed limit of 30 mph before and after the school zone. Note: it may be possible to reduce surrounding 35 mph zones to 30 mph using other criteria to allow for this option.

(Signage required, Exempt from certain speed trap provisions, Ordinance/resolution required)

As an example, using AB 321 (2008), the City of Sacramento implemented 15 mph school zone speed limits and/or 25 mph extended school zone speed limits across 225 road segments near 115 schools. Access this case study here (Mancebo 2019). 

Sample Administrative Reports: 

  • City of San José: Resolution Establishing Speed Limits (Larsen 2010)
  • City of Los Angeles: Implementation of School Safety Zone Speed Limits (Reynolds 2016)
  • City of San Mateo: School Zone - Speed Reduction (Corbett 2021)   
  • City of Sacramento: Vision Zero Implementation: Reducing School Zone Speed Limits (Mancebo, Donlon-Wyant, Moore 2019)

Sample Resolution:

Sample Reports: 

  • City of Walnut Creek: Recommendations Report for Reduced School Zone Speed Limits (TJKM 2016).

4. Business Activity Districts (AB 43 change)

Newly created under AB 43, business activity districts can be established in commercial areas such as downtowns and neighborhood business corridors if the land use and roadway meet certain conditions. Roads in business activity districts may have a prima facie speed limit of 20 or 25 mph without the need for an E&TS. Refer to CVC § 22358.9 for the specific definitions of business activity districts.

Example of Business Activity District with High Pedestrian and Bike Activity

Image of people talking and standing around a bike rack. g

Source: Adventure Cycling Association 

To qualify as a business activity district, the following criteria should used to assess a corridor:

a. All of the following must be true: Located in commercial areas such as downtowns or neighborhood business corridors AND on a road with four or fewer travel lanes. 

b. AND 1 of the following must be true: 

i. A maximum posted speed limit of 30 mph before and after a proposed 25 mph business activity district.  Note: it may be possible to reduce surrounding 35 mph zones to 30 mph using other criteria to allow for this option. 

ii. A maximum posted speed limit of 25 mph before and after a proposed 20 mph business activity district. Note: it may be possible to reduce surrounding 30 mph zones to 25 mph using other criteria to allow for this option.

c. AND contains at least 3 out of 4 of the following:

i. At least half of the contiguous properties are for retail or dining commercial uses. 

ii. On-street parking. 

iii. Signals or stop signs are located at intervals of no more than 600 feet.

iv. Marked crosswalks that are not controlled by a traffic control device.

(Signage required, Exempt from certain speed trap provisions, Ordinance/resolution required, AB 43 changes)

Example of a Business District with Many Shops and High Pedestrian Activity

Image of pedestrians crossing the street in San Francisco’s Chinatown.

Source: Curbed San Francisco

Business activity districts with 20 mph or 25 mph speed limits cannot be established on roads that have leveraged any of the other AB 43 changes (see sections 5,6,7 below): further reducing the speed limit by 5 mph using the designations of “safety corridor” or “high concentrations of bicyclists or pedestrians” or when retaining the existing or restoring the immediately prior speed limit. Therefore, local jurisdictions can consider implementing 20 mph or 25 mph business activity district speed limits prior to implementing other elements of AB 43 changes. 

The City of San José has implemented 20 mph business activity district speed limits on 6 corridors both in downtown and other commercial areas (City of San José 2022).

Example of a Business Activity District with Many Retail Uses

 Image of a retail district with pedestrian traffic and a 20 mph speed limit sign.

Source: San Francisco Chronicle

Sample Project Website: 

  • City of San José: Speed Limit Lowered in San José Business Areas (City of San José 2022

  • City of Oakland: Lowering Speed Limits in Business Activity Districts (City of Oakland n.d.)

  • City of Los Angeles: Mapping AB43 Speed Limit Reduction in Los Angeles (LADOT n.d.)

Sample Administrative Reports: 

  • City of San José: Memorandum for establishing business activity district speed limits (Ristow 2022)  

  • City of Oakland: Report on establishing business activity district speed limits (City of Oakland 2022)

  • City of Los Angeles: Report listing roads on which speed reductions are proposed (Reynolds 2022)

Sample Resolution:

5. Land or Facility that Generates High Concentrations of Bicyclists or Pedestrians (new changes under AB 43)

“Land or facility that generates high concentrations of bicyclists and pedestrians” (a.k.a. high concentration of bike and ped) is one of two options under AB 43 to reduce the speed limit by 5 mph in the E&TS process (see CVC § 22358.7(a)(2))). The other option is a Safety Corridor (see #6 below). If the 5 mph reduction is taken for a Safety Corridor, then the 5 mph for high concentration of bike and ped cannot be applied. Areas with high concentration of bike and ped may be places such as parks, transit hubs, or outdoor recreational centers that attract a considerable number of pedestrian and bicycle trips (NACTO 2020). They may also simply be areas with designations for bicyclists or pedestrians, such as roadways with marked bike lanes or streets with sidewalks. This 5 mph reduction is not yet available for local jurisdictions to implement (pending eligibility conditions under CVC § 22358.7(c)), but jurisdictions can begin to plan for this reduction and will be able to implement it where appropriate no later than June 30, 2024. Once available, this reduction can be applied to locally-controlled roads only. 

Definition 

Roadways with high concentration of bike and ped can be defined in two ways. 

  One of the following: 

  • Falling within 1320 ft of any generators listed in CA MUTCD Table 2B-106(CA) (see below)

  • Within 1320 ft of a top 20% hotspot for pedestrian and/or bicyclist fatalities or serious injuries

Requirements to determine Land or Facility that Generates High Concentrations of Bicyclists or Pedestrians (Table 2B-106 (CA))

Generators related to Land Use: 

  • Employment centers 

  • Presence of retail 

  • Parks, multi-use trails, and recreational destinations 

  • Schools/universities

  • Senior Centers 

  • Cultural areas, entertainment space areas, or areas of community significance

  • Religious facilities 

  • Health/medical facilities

Generators related to Transit Factors:

  • Transit stops 

  • Transit Oriented Developments/Transit Priority Areas

Generators related to Presence of Pedestrian/Bicyclist Infrastructure:

  • Sidewalk presence 

  • Crosswalk presence 

  • Bikeway presence 

  • Nearby signalized intersections on four-way intersections 

  • Presence of micromobility devices such as bicycles or scooters

Generators related to Demographic Factors:

  • Presence of vulnerable groups including children, seniors, persons with disabilities, users of personal assistive mobility devices, and the unhoused

  • MPO/RTPA or locally defined disadvantaged community status 

  • Presence of students (all levels)

Generators related to Local Data:

  • Need identified in a safety analysis such as a road safety audit or formalized planning document such as a local road safety plan

Source: Adapted from California Manual on Uniform Traffic Control Devices (CA MUTCD) (California Department of Transportation 2023)

Falling within 1320 ft of any generators listed in CA MUTCD Table 2B-106(CA)

Infographic detailing a generator and a sidewalk.

At least one generator for every 1320 ft / 0.25 mi

Infographic detailing a generator and a sidewalk with a bus stop.

Road segment within the top 20% of pedestrian and/or bicyclist fatalities or serious injuries

Infographic detailing a sidewalk with pedestrians and bicyclists.

(Exempt from certain speed trap provisions, Ordinance/resolution required, AB 43 changes) 

Practical Considerations

The list of generators is comprehensive and presents an opportunity for local jurisdictions to flexibly apply the 5 mph further reduction. Any generator in CA MUTCD Table 2B-106(CA) can qualify a street as a “roadway with high concentration of bike and ped”. Notably, generators such as sidewalk presence and crosswalk presence are very common, especially in urban areas.

6. Safety Corridor (new changes under AB 43) 

A Safety Corridor is defined as a roadway segment within an overall roadway network (no more than one-fifth of the total network) where the highest number of serious injury and fatality crashes occur (see CVC § 22358.7(a)(1)). Safety Corridor designation is the second of two options under AB 43 to reduce the speed limit by 5 mph in the E&TS process (the other being high concentration of bike and ped (see #5 above). If the 5 mph reduction is taken for high concentration of bike and ped, then the 5 mph for a Safety Corridor cannot be applied. This 5 mph reduction is not yet available for local jurisdictions to implement (pending eligibility conditions under CVC § 22358.7(c)), but jurisdictions can begin to plan for this reduction and will be able to implement it where appropriate no later than June 30, 2024.  Once available, this reduction can be applied to locally-controlled roads.

Safety Corridor and High Injury Network 

Safety Corridors can be determined through a High Injury Network (HIN) analysis that satisfies the required specifications under the MUTCD (Ferrier 2018). The Recommendations for California Statewide Guidance on High Injury Networks document summarizes the methodology for developing a HIN and points to numerous California case studies (“Recommendations for California Statewide Guidance on High Injury Networks” 2021). The guidance document delineates the standards of eight core components for a HIN and provides a checklist of HIN development for local jurisdictions. 

The HIN should represent a defined prioritized subset of the overall transportation network. Specifically for Safety Corridor designation, the HIN should be consistent with all the following requirements (refer to the MUTCD summary of changes for the complete list of requirements for Safety Corridor designation):  

  • Based on fatal and serious injury crashes

  • Uses three to five years of the most recent crash data 

  • Safety Corridor designation cannot exceed 20% of the local jurisdiction's roadways

  • Identify specific locations with high crash occurrences

  • Identify corridor-level segments with a pattern of crash reoccurrence 

  • Be able to be stratified by mode

  • Uses at least one required crash weighting factor listed in Table 2B-105(CA) (see below) to prioritize locations

Safety Corridor Definition Requirements (Table 2B - 105 (CA)):

  • Crash Weighting Factors to Develop One Serious/Fatal Injury Safety Corridor: Crash weighting can be developed using fatal and serious injury crash data and other factors to prioritize safety corridors. Suggested weighting factors are as follows: 
    • Crash severity: Fatal Crashes, Serious Injury Crashes 

    • Mode: Pedestrian-bicycle related crashes, vehicle/other 

    • Disadvantaged Community Status: MPO/RTPA or locally defined disadvantaged community status based on most current version of CalEnviroScreen

    • Vulnerable Populations: Seniors (age 65 and older) and Youth (under age 15) based on the American Community Survey 

    • School proximity (within 0.25 miles) based on the California School Campus Database

  • Crash Density

    • Each roadway segment block can be converted into ~ 0.25 mile overlapping "corridor" segments to create a consistent unit of measurement and assess the concentration of linear patterns of injuries within a defined distance. The highest scoring (i.e. most fatal and serious injury crashes per mile) "corridor" segments within a street needs to be identified and an appropriate threshold set to determine safety corridor eligibility.

  • Maintenance
    • The jurisdiction can establish a review and re-evaluation frequency for Safety Corridors. However, such frequency need not exceed seven years.

Source: Adapted from Table 2B-105(CA): Safety Corridor Definition Requirements, on Uniform Traffic Control Devices (CA MUTCD) (California Department of Transportation 2023)

(Exempt from certain speed trap provisions, Ordinance/resolution required, AB 43 changes)

Practical Considerations 

Safety Corridors connect HINs with Speed Limit Setting. Local jurisdictions that have developed HINs may need to determine their conformance with Safety Corridor requirements prior to utilizing speed limit setting flexibility based on the Safety Corridor designation. 

For local jurisdictions that have not developed HINs, the requirements for Safety Corridor designation and best practices can serve as guidance for their HIN development efforts (“Recommendations for California Statewide Guidance on High Injury Networks” 2021). Safety Corridor designation might also be informed by analysis completed for a Local Road Safety Plan (LRSP) or Systemic Safety Analysis Report Program (SSARP). If none of these analyses (HIN, LRSP, SSARP) have been completed, jurisdictions can likely use crash data to designate a single corridor as a Safety Corridor, but this would require an objective analysis showing that the corridor’s safety issue is elevated when compared with the rest of the community or statewide averages. See the section on Collecting Supporting Materials to Enact Reduced Speed Zonesfor more information on data sources for this type of analysis. 

Minimum core component standards for developing a High Injury Network

ComponentComponent Standard
YEARS OF DATAAn HIN should depend on between three and five years of crash data from a reliable source of data (up to 10 years may be appropriate, depending on the jurisdiction). Crash data may be derived from SWITRS, TIMS, or a jurisdiction's established database.
SHARE OF ROADWAY NETWORKAn HIN should represent a subset of an overall roadway network - typically between 5 percent and 20 percent. Jurisdictions should aim to identify a share less than 50 percent of the total roadway network as the HIN, to support a focused approach for future investments.
LEVEL OF ANALYSISAn HIN should be focused on corridors that are continuous and have comparable crash patterns or densities - considerations for corridor length can include land use, speed, and intersection spacing.
COLLISION DENSITYAn HIN should have a development threshold that captures a significant number of total fatal and serious injury crashes - typically more than 40 percent.
ROADWAY FACILITY TYPESAn HIN should consider roadway facilities particularly ones for which they have the authority to establish speeds or conduct enforcement.
EQUITYAn HIN should take into account equity. For example, a jurisdiction could document how much of the proposed HIN falls into communities of concern or disadvantaged communities, or through more heavily weighting crashs occurring in these areas.
CONSIDERATION OF MODES(e.g., driver, bicyclist, pedestrian, etc.) An HIN should consider all modes of serious and fatal crashes, including bicyclists and pedestrians.
MAINTENANCEAn HIN should be re-evaluated when speed limits are surveyed/modified, land use characteristics change, data changes or other relevant changes occur.

Source: Adapted from Recommendations for California Statewide Guidance High Injury Networks (“Recommendations for California Statewide Guidance on High Injury Networks” 2021)