The police officer's story was that I went through just after the light had changed from yellow to red. That's not out of the question; I have misjudged yellow lights before.
However, I have no memory at all of doing so today. I don't remember hoping that I would make it through before the light changed; I don't remember any yellow light at all.
I've spotted three possible explanations for this discrepancy:
1. The officer was wrong or lying.
2. I sailed through a yellow light without noticing.
3. Something about the light made the officer see it very differently from me.
All of these alternatives are concerning. #2 and #3 have serious implications for public safety. #1 has serious implications of its own.
I don't know how to disambiguate those explanations or what to do about the ticket.
This is my first incident in over ten years, so the consequences of pleading guilty are not that big a deal right now.