Too easy to spoof. If I were a magistrate, I would never accept a cop's (or anyone else's) photo with a date and time stamp as proof of anything more than that whoever set up the camera knew how to turn on the date and time stamp function.
Chalk marks are even less evidence.
That said, I don't think that mounting cameras on poles is going to be a long term solution. Probably hit the ilfespan of the cameras if you install today, but in 5-10 years I figure self driving cars will be coming out, and that will be a real game changer when it comes to enforcement of all vehicular offenses.
To wit, you'll hardly ever be able to collect any money from violations. If you hand out a ticket to the self-driving car, the maker will make it so the car doesn't do that anymore, and global update. If they think the ticket was issued erroneously, they'll fight it for the principle of the matter.
If you try to ban them(in the local area), they'll hit you over the head with the safety improvements.
Charge for parking? People will simply have their cars drop them off then go somewhere to park for free(unless the miles to do so is more expensive than paying).
Parking is time limited? Car moves itself.
Speeding? Running a red light? Hah! Expect to pay big bucks attempting to justify your ticket when the maker of the AI shows up with an excessive number of lawyers who have been prepping for just this fight and video showing that they didn't do it.
I remember the judge for the first speeding ticket involving a GPS tracker case still found the kid guilty on the assumption that he
could have been speeding at the moment the cop radared him, if the kid accelerated(in a not very powerful car) like a sprint car then decelerated back to below the speed limit in just the 4 seconds between logging the speeds. The parents had paid for the defense because, well, they installed the GPS tracker after a previous incident of speeding, the kid knew it was there, and the evidence they had was that the kid hadn't been speeding when the cop stopped him.
But it was a very pyrrhic victory for the city. Besides the parents funding a good defense, the maker of the tracker sent their own assistance and expert witnesses. So the city spent like 100 times the amount of the fine to convince one judge to still rule guilty.
The makers of GPS trackers took the Judge's reasoning into account and changed their tracking systems and logs a bit so that the judge couldn't say "maybe could have". The police/cities have subsequently lost in court.
I figure the same deal, but more so, with self driving cars. Keep a rolling log of the sensors(including cameras) while it is operating. If it's pulled over, bake the last half hour to hour of data into permanent storage.