I too am sorry for your accident but glad that you are OK. Police are not always impartial. I once had a friend in the early 20s (age not era) who was involved in an accident. He was charged with speeding but when he told the officer that the charger was not his car but the middle age women the charge was changed to proceeding when unsafe to do so.
If you pulled out on a green light while vehicles were coming into the intersection you are not totally innocent but partially guilty. A green light just means that you have the right to proceed if safe to do so. I would get legal assistance and fight this in court. It matters more on how a judge views the witness then the police do. I once beat a charge of careless driving and had a police officer actually witness the scene as he was in the lane next to me. The second officer on the scene could do nothing as he was my parent's neighbour and the fools who wrote it up measured the skid marks that were there, which went way beyond where the vehicle I rear ended stopped, in other words I would have had to hit the brakes, skidded to a stop and backed up and rear ended the car.
Write up exactly what happened, as best you can and then get legal advice. As far as the lawyers go, a good one saves you money and they need to earn a living. The police should never be the final say in any matter, oft times evidence comes to light after their investigation for example .
Good luck and again glad you are OK
---------- Post added 11-28-16 at 10:15 AM ----------
Originally posted by vonBaloney As a point of interest, when I was 17 I totaled my car by running a red light that had just turned (completely my fault) and got clipped in the rear bumper by someone going through the green, which sent me into the center island and the car actually did a complete roll. No injuries. Whole thing was witnessed by a cop who happened to be waiting at the same intersection. So naturally he gave me a ticket. Not long later I get a letter in the mail saying the ticket is voided (though I took no action to contest it) because the officer who gave me the ticket was a witness to the accident, and apparently can't both be ticket-giver and witness. He was supposed to call in someone else for that I guess. Seems weird because if are witnessed by an officer committing a normal crime, I'm pretty sure they will be the same one to arrest you.
And speaking to Pentax toughness, another time when shooting I fell in a gorge and broke my wrist, broke my nose, and shattered my elbow. (Requiring surgery on both elbow and nose.) The K1000 had a little dent, but continued to operate perfectly for many years....
I think in the case of an officer witnessing a crime, they will detain the culprit and call in another officer to be in charge of the case and to file the arrest warrant and charges. It protects the public or that is the intent.