You lots and lots of options. Let me give only a few here.
You can have an actual real trial in court is what "de novo" means in those papers. Note that it is rare to win these little ticket infraction court trials ... which results in potentially higher fees/fines and the same speeding infraction conviction with DMV points - which you could ask the judge for traffic school to get the points removed from your driving record.
If youmainly care about the points on your DMV record and the money [as opposed to an infraction conviction which is nothing] you can show up to court [putting your matter on calendar before hand] and try and negotiate [with the cop and judge - typically a prosecutor is not present] a no contest/guilty plea to non-moving violation to avoid DMV points and lower fines. Coasting is a good infraction to plead to if you decide to negotiate/plead/give up court trial rights to fight the speeding charge b/c no DMV points associated with coasting.
Note, if you want a real trial "de novo" here in court to fight the speeding infraction [i.e. avoid negotiation to a different offense with less fines], check out the speed trap rules and see if they help your cause. The speed trap statutory scheme is found in Cal Vehicle Code Sections 40801 through 40805. Also note Cal Veh Code 40503, requiring the cop to articulate certain things on the ticket for speed charges. Maybe these rules will help you if you want your real court trial.
You cannot request evidence with a TBD. All you do is submit a statement as to why you believe you were not gulty of the violation. The officer who wrote your citation does not even see what you wrote. The officer responds as to why he wrote the ciation against you. The responses are reviewed and a decision is rendered. When you filed the TBD you posted the bail amount which included the fine and penalty assessments. You have 20 days from the date of the decision to request a trial de novo. There are forms to be filled out for this request. An additional $20 filing fee is required. It certainly is worth it to do if that time has not already past.
File a request for a Trial de Novo immediately. A trial by written declaration is frequently a waste of time, but the downside is minimal for most people. They are won occasionally, but you have a much better chance at trial.
My advice is to hire an excellent traffic attorney in Los Angeles and let them take care of it.
If you continue to represent yourself, I recommend that you look at the Nolo Press publication on how to fight and win your traffic court cases in California. I agree that if you want to maximize your chances of winning, you should hire a traffic ticket attorney. You can get the types of items you requested, but not the way you attempted to get them. You have to serve the agency with a discovery request in advance of your next court date. You cannot simply show up to court and ask them to give you items.