San Mateo speed survey, 2026 · All 123 streets

S Grant St, 10th Ave to Haddon Dr

On S Grant St between 10th Ave and Haddon Dr, the limit is 25. Half of drivers go faster than 23; the fastest 15% go faster than 26.

Current limit: 25 mph
Proposed: 25 mph
Lowest legal option: 20 mph

What state law allows here

25 mph using the survey's numbers alone (CVC 22358.6(a)).
20 mph with an additional 5 mph reduction (CVC 22358.7). The city must find the limit is still more than is reasonable or safe, and the street must qualify one of two ways. The law allows it on a designated safety corridor; the state's traffic manual defines these as the streets with the most deaths and serious injuries, and the law caps them at a fifth of city streets. The law also allows it next to places that draw many people walking or biking, such as a school, park or transit stop; the manual adds that the street must rank in the city's worst fifth for people walking or biking killed or seriously injured over 3 to 5 years.

Surveyed April 9, 2026. Sample size: not reported on the survey sheet. Average daily traffic 2,183 vehicles. The fastest 15% go 1 mph over the limit. Survey sheet (PDF page 84).

For a person walking, the average risk of death is about 10% if struck at 23 mph and about 25% if struck at 32 mph. These are impact speeds, the speed at the moment of the crash (AAA Foundation for Traffic Safety, Tefft 2011).

Options for collectors like this one

The survey classifies this segment as a major collector. Typical effects, from federal research:

Bike lanes: up to 30% fewer crashes overall on urban two-lane collectors, and up to 49% on four-lane ones (FHWA Proven Safety Countermeasures, FHWA-SA-21-051).
High-visibility crosswalk: up to 40% fewer pedestrian injury crashes; advance yield markings, up to 25% fewer pedestrian crashes (FHWA Proven Safety Countermeasures, FHWA-SA-21-049).
Flashing beacon at a crosswalk (RRFB): up to 47% fewer pedestrian crashes at uncontrolled marked crosswalks (FHWA Proven Safety Countermeasures, FHWA-SA-21-053).
Chicane (alternating curb extensions): on two-lane, two-way streets, 85th-percentile speeds averaged 31 to 33 mph after installation (FHWA Traffic Calming ePrimer, Module 4, Table 4.1).

The city's 2006 traffic calming policy does not allow speed humps, traffic circles or other physical calming devices on collectors or arterials, so changes on these streets come through city street projects. The city's Local Roadway Safety Plan lists its priorities. For reference, this segment does not pass the policy's speed test: the fastest 15% go 1 mph over the limit, and the test is more than 7. The survey doesn't measure cut-through traffic, so the policy's volume test can't be checked here.

Ask the city

This opens an email to Council Member Newsom (District 3) and Jay Yu, Engineering Manager, with this street's numbers filled in. There's a blank line for a sentence of your own.

To: rnewsom@cityofsanmateo.org, jyu@cityofsanmateo.org
Subject: Speed limit on S Grant St (10th Ave to Haddon Dr)

Dear Council Member Newsom and Engineering Manager Yu,

The city's 2026 speed survey measured traffic on S Grant St between 10th Ave and Haddon Dr on April 9, 2026. The limit there is 25 mph. Half of drivers went faster than 23 mph, and the fastest 15% went faster than 26 mph. The survey proposes keeping the limit at 25 mph.

State law would allow a limit as low as 20 mph on this street, with an additional 5 mph reduction, if it qualifies as a safety corridor or as a street near places that draw many people walking or biking (Vehicle Code 22358.7).

Add a sentence of your own here.
Will the city set the lowest limit state law allows on this street?

Write the email

Council members as of October 25, 2026, by the districts this segment crosses. Jay Yu is the staff contact named on the speed limit update; the city lists no general Public Works email.

S Grant St, 10th Ave to Haddon Dr

What state law allows here

Options for collectors like this one

Ask the city

Share this street