How Do Red Light Cameras Work? Complete Explainer

General information · Updated 2026

A typical red light camera system combines signal timing data, vehicle detection and image capture, but vendors and jurisdictions use different equipment and review procedures.

Detection and capture

Depending on the installation, roadway loops, radar or video analytics can detect an approach and trigger images or video. Data overlays may record time, signal phase and elapsed red time. Exact trigger rules come from the local system.

Plate and event review

Software may help read a plate, while authorized reviewers may assess the captured event before a notice is issued. The level and legal significance of human review vary by program.

Notice and response

If the agency approves an event, it may send a notice to the registered owner under local rules. Timing, required contents, owner liability and response options are jurisdiction-specific.

Check the governing jurisdiction

Use our state summary as a starting point, then verify current rules with the issuing agency or linked statute.

View laws by state

Frequently asked questions

How accurate are red light camera systems?

Performance depends on the equipment, installation, signal data, maintenance and review process. A national accuracy figure cannot resolve a specific notice.

What triggers the camera?

The trigger can combine signal phase with loop, radar or video detection. The local system documentation controls.

Does every captured event become a citation?

No. Programs can reject events for unreadable plates, insufficient evidence or other review criteria.