This is half true. ANYTHING the crown intends to present to the court as evidence must be turned over, BUT they are NOT required to disclose and "evidence" that they are not offering in court.
As for witness info, you are NOT entitled to their addresses, or criminal background, (you MAY, BUT only if the court deems it relevant), ask them, if they have any CRIMINAL convictions. It is highly unlikely the crown or the JP will permit that line of questioning as it bears NO relevance as to their ability to testify as to YOUR actions.. About the ONLY circumstance I can off the top of my head think where a criminal conviction may be germaine, is if the witness had been convicted of perjury, (which is HIGHLY unusual, there are likely less than 10 people per year even charged with that offence.
As for what a witness WILL say, The crown, will argue, (successfully), that they have NO idea what a witness MAY or may not say while testifying. UNLESS this is a SERIOUS CRIMINAL charge, it isn't like TV where the crown "Preps" the witnesses. It is TRAFFIC court. Also unless, it is a serious HTA charge, and the ONLY way for the crown to prove it's case is by having the witness(s) tesify, they likely won't even be subpoenaed, Rather the crown will rely upon the officer's testimony to prove it's case. That is WHY they are testifying. You will have an opportunity to question them, (but ONLY about what they state or what they wrote if a WRITTEN statement was given). If they only provided a verbal statement, that would be included in the officer's notes.
Certainly, IF a written statement was provided, then read it over, see if there are any GLARING, items wrong. They say the offence happened in July, when it was actually December. If they get small details incorrect, (Street names, or say it was in Etobicoke when it was in Toronto, The JP will rule that those are MINOR issues, As long as the officer has it correct. The court WILL rule, that witnesses, are permitted to make minor errors, The Officer WILL establish where the offence occurred, the court will only want to hear what a witness seen that lays out the "elements" of the offence.
As for defendant's statement, IF you provided one then it will likely be provided, although the crown can argue, (Unless they present it to the court as evidence), YOU should know what YOU said..lol
In reality, unless this is a SERIOUS CRIMINAL driving offence, Not just an HTA offence, you have to remember, it is a JP NOT a judge, and as such, the court will have VERY little tolerance for a defendant, who goes all "Perry Mason" in an attempt, to find a loophole.
Lastly, the crown is NOT obligated to disclose, ANY evidence that they are "relying upon", (presenting to the court as evidence of the "elements" of the crime. IE if the cruiser has a dash cam, (which didn't record the actual offence, IE the officer was called to the scene). Nor, is the crown, again if they are NOT relying upon such information), need to disclose why they are NOT presenting it, (unless of course it exonerates you), IE dash cam video shows you did NOT run a red light, as the cruiser was following you, and recorded, the colour of the light. Again keeping in mind this is TRAFFIC court, your likely charged with a MINOR HTA offence, your not being tried for 1st degree murder...lol
Hopefully, this assists you in your defence, But I am NOT a lawyer, Just an ex copper who likely testified thousands of times in court, (traffic, all the way up to appeals court.
Good luck
They have to provide you with what ever evidence they will use in court against you . Plus all evidence they have collected .
