When you mail your request to the police department, mark the envelope "Attention Custodian of Records". That is the person responsible for addressing your request.
Include a copy of you citation, as doing so makes it easier to fulfill your request. Officers traditionally write their notes on the back side of their copy of the citation that was issued to you. That copy is kept in the citing officer's custody and must be manually searched by hand. Having a copy of the citation makes it easier for the officer to search.
If you are seeking discovery from a local police or sheriffs department I would suggest not using the sample discovery request Zeljo provided you. I say this for a couple of reasons. First, the language and terms used (MVARS) suggest it was written for someone seeking discovery from CHP. MVARS is an acronym specific to CHP and refers to audio and video patrol car recordings. However, it has no meaning in the terminology of local agencies and you may not get any video or audio, even though they may exist. Similarly, Zeljo's exemplar does not request copies of any personal recordings made by the citing officer.
As a former Custodian of Records I can tell you that while I am obligated to follow the law, I am not required to be on your side or assist you in your case. i may have a very good idea of everything what you want and need, but unless you specifically articulate each and every item being sought in your discovery request, you're not going to get it.
You may wish to seek the following in you discovery request:
When seeking informal discovery on a California traffic citation, mail a copy of your citation to the law enforcement agency that issued it. Clearly address the envelope to “Custodian of Records” and attach a letter indicating you are requesting informal discovery in connection with the enclosed citation. In addition to any items you feel are necessary to your defense, be sure to ask for:
1. A copy of the officer’s copy of the citation, including the back side containing any notes he may have made.
2. Copies of all other notes, reports and other documents prepared by the officer in connection with the matter.
3. If you were cited for speeding, copies of calibration records for all speed measuring devices used to determine your speed.
4. If you were cited for speeding, a copy of any traffic and engineering surveys for the highway in question (if applicable).
5. Copies of the patrol car dash cam video and audio recording of your stop (if any exist).
6. Copies of any personal audio recording the officer may have made during his contact with you.
Items 1 & 2 will give you an idea as to what the officer may testify to.
Item 3 will determine if the device used to determine your speed was recently calibrated.
Item 4 will probably not be applicable unless you were written for CVC 22350.
Items 5 & 6 are valuable because during the traffic stop, drivers tend to make all sorts of incriminating statements that the officer will offer in court if you deny having committed the violation. It’s difficult to convince the court you are innocent if the officer recorded you admitting the violation. Words mean things, so it’s best to know what you said ahead of time, to ensure you don’t make a fool of yourself in court.