How to Request Discovery for Your California Traffic Ticket

Most drivers never request discovery before filing a Trial by Written Declaration under CVC 40902 (Trial by Written Declaration) or contesting a CVC 22350 (Basic Speed Law) citation. Most drivers also just pay their tickets. The two things are related.

What Is Discovery in a CVC 40902 Traffic Case

In California traffic cases, "discovery" refers to the exchange of evidence between both sides of a case. As a defendant contesting a citation, you have the right to see the evidence the prosecution plans to use against you.

Discovery is not about arguing your version of events. It is about understanding what evidence exists so you can evaluate whether that evidence is reliable.

Why Discovery Matters for Your Defense

A traffic citation — such as a CVC 22350 citation — is a claim that you violated a specific section of the California Vehicle Code. The prosecution has the burden of proving that claim. Without knowing what method the officer used to determine your speed, or whether the equipment was properly calibrated, or what the officer training record looks like, you are building a defense based on assumptions.

Discovery eliminates assumptions.

What to Request

A discovery request should ask for specific, material evidence related to the reliability of the citation. Common items to request:

• Method of speed determination (radar, laser/LiDAR, pacing, visual estimate)
• Device serial number and date of last calibration
• Officer training records (POST certification for the device used)
• Officer notes made at the time of the stop
• Distance from the device to the target vehicle at the time the reading was taken
• Position and direction of the officer's vehicle
• A legible copy of the original citation
• An explanation of any abbreviations or codes on the citation
• Any diagrams, drawings, or supplemental notes made by the citing officer

How Speed Is Measured in California

Four primary methods are used to measure speed in California:

Radar: Radar devices emit radio waves and measure the frequency shift of the returned signal. Weaknesses include beam spread at distance, multi target interference, and calibration accuracy.

Laser (LiDAR): Laser devices emit pulses of light and measure the time it takes for them to return. Accuracy depends on distance, device stability, and proper targeting. A handheld device at 1,000 feet requires extremely steady aim.

Pacing: The officer follows your vehicle and matches speed using their own speedometer. Accuracy depends on maintaining a consistent following distance over a sufficient period.

Visual estimate: The officer estimates your speed by observation. This is the least precise method but is still used, particularly for extreme speed violations.

Each method has different vulnerabilities. Discovery tells you which method was used so you know what to address.

Where to Send Your Discovery Request

1. The citing officer, addressed through the law enforcement agency where the officer is employed (primary recipient)
2. The court clerk handling your case (copy for the case file)

Send all copies via certified mail with return receipt requested. This creates a documented record that your request was sent and received.

What Happens After You Send It

Three possible outcomes:

The officer responds with complete evidence: You now know exactly what method was used, what device was involved, when it was last calibrated, and what the officer training record looks like. You can tailor your declaration to address the specific evidence.

The officer responds with incomplete or missing evidence: You may receive partial records, missing calibration documentation, no training records, or vague answers. Incomplete discovery responses weaken the prosecution's ability to establish the reliability of their evidence.

The officer does not respond at all: Also common. If the officer fails to respond to a properly served discovery request, you document this in your declaration. The failure to provide evidence can be used to argue the prosecution cannot meet its burden of proof.

How to Use Discovery Responses in Your Declaration

The argument structure:

1. The prosecution must prove your speed
2. That proof depends on reliable evidence
3. You requested that evidence through a formal discovery process
4. The response was incomplete, unreliable, or nonexistent
5. Therefore, the evidence does not meet the standard required

About Illegible Citations

Many citations are difficult to read, full of abbreviations, or partially illegible. While an illegible citation alone is not grounds for dismissal, if you cannot read the citation, you cannot evaluate the evidence, and you cannot prepare an adequate defense. Request a legible copy and an explanation of all abbreviations as part of your discovery request.

About Missing Distance Information

Officers used to routinely record the distance from their position to the target vehicle. Many no longer do. Distance matters because radar beam spread increases with distance, laser accuracy depends on distance and stability, and greater distance increases the chance of targeting the wrong vehicle. If no distance was recorded on the citation and no distance was provided through discovery, that gap is worth noting in your declaration.

Discovery Request Template

Use this template as a starting point. Fill in your case details and send via certified mail with return receipt.

Send the original to the law enforcement agency. Send copies to the court clerk. Send everything certified mail, return receipt requested.

TicketClear handles this for you. When you use TicketClear, our technology builds your entire Trial by Written Declaration based on the specific details of your citation, including arguments that address evidence reliability, calibration, officer procedures, and more. You answer questions about your stop, and we generate the complete declaration and mail it directly to your court. Discovery is one piece of the puzzle. TicketClear builds the whole picture. Check if my ticket qualifies →