Car crash statistics in Diamond Bar, CA

We don't rate cities as safe or unsafe: crash counts can't say how risky a street is, and busy streets have more crashes partly because more people use them. This page covers traffic crashes, not crime. What the records show: 7,235 crashes were reported in Diamond Bar from 2021–2025, 1,857 with an injury and 28 with a death. 26% (California: 40%) of crashes injured someone. 20% (California: 25%) were hit-and-run.

• 26% (California: 40%) of crashes injured someone.
• 20% (California: 25%) were hit-and-run.
• 19% (California: 26%) happened between 8 p.m. and 6 a.m.
• The busiest hour was 3 p.m. (California: 5 p.m.).
• 76% were on a freeway.

Set against all reported crashes in California, 2021–2025. Without traffic counts these can't say how risky a street is.

The main cause the reporting officer recorded, as a share of all 7,235 crashes. It is the officer's judgement at the scene.

• Unsafe speed42% · 3,019
• Straying from the lane or driving on the wrong side28% · 2,024
• Unsafe turning or lane change10% · 741
• Failing to yield at an intersection or to turn3% · 240
• Running a red light or stop sign3% · 213

By type of collision: rear end 45%, side swipe 34%, hit object 9%, broadside 6%.

The latest year can rise as late reports come in, and some police departments file months late.

• 66 crashes (1%) involved a pedestrian. See where they cluster
• 25 crashes (under 1%) involved a bicyclist. See where they cluster
• 153 crashes (2%) involved a motorcyclist. See where they cluster

How many car accidents happen in Diamond Bar each year?

Reported crashes in Diamond Bar: 2021: 1,445, 2022: 1,415, 2023: 1,527, 2024: 1,492, 2025: 1,356. The latest year can rise as late reports come in, and some police departments file their reports months late.

What time do most crashes happen in Diamond Bar?

The busiest hour for reported crashes in Diamond Bar is 3 p.m.. 19% (California: 26%) happened between 8 p.m. and 6 a.m.

What causes crashes in Diamond Bar?

The main cause the reporting officer recorded, as a share of all 7,235 crashes: unsafe speed 42%, straying from the lane or driving on the wrong side 28%, unsafe turning or lane change 10%, failing to yield at an intersection or to turn 3%, running a red light or stop sign 3%.

How many people were killed in crashes in Diamond Bar?

28 crashes killed someone in 7,235 reported crashes in Diamond Bar from 2021–2025, and 1,857 crashes injured someone.

How many crashes in Diamond Bar involve pedestrians, cyclists or motorcyclists?

66 involved a pedestrian (1%), 25 involved a bicyclist (under 1%), 153 involved a motorcyclist (2%), of 7,235 reported crashes from 2021–2025.

Where does this data come from?

Police crash reports in the California Crash Reporting System (CCRS), published by the state on data.ca.gov. Every reported crash is counted, whatever the vehicles, and no locations are used.