Hardly believable

Traffic infractions have to be witnessed by law enforcement personnel to be valid. It's not the officer's fault, that is the law.

If you had dashcam video, it would be different as that can be used as evidence in court as long as a few things are present and verifiable, like the date and time of the video. But without it, the whole thing will come down to your word vs. the word of the other driver, who will likely deny everything. The marks on the pavement and on the shoulder could have been made by anyone, and the gravel and weeds in the other drivers car could have come from somewhere else. While you know that's not the case, the evidence doesn't prove it beyond a reasonable doubt. Knowing what happened and proving what happened in a court of law are two different things, and they SHOULD be.

Don't get me wrong, I ride a motorcycle and would love for people to actually follow the damned traffic laws. I've nearly been taken out more times than I can count by folks that didn't use their signals, or bothered to look before they changed lanes, made an illegal u-turn, whatever. But I also wouldn't want to be cited because someone doesn't like motorcycles, or thought my bike was too loud, or fast, or whatever, and made up a story and told the police something that wasn't true to get me cited, fined, or worse.