In TX, I've served as a juror a couple of times in traffic court - each time, it was made clear that these traffic offenses were considered criminal infractions, and the persons had a constitutional right to a trial by jury.
I think its the same here...
The last time my wife got a speeding ticket, she went to her court date instead of just paying the fine.
They gave her three options:
1. Pay the fine as-is, and get a few points on her license.
2. Plea bargain to a broken speedometer, pay a fine that was $50 or so higher but no points on her license.
3. Trial at a later date.
They make the fines cheap enough that no sane person unless independently wealthy, retired with a lot of free time, or is trying to make a point is going to go to trial.
It works almost the same way for parking tickets- at least in Milwaukee- a private contractor with incentives to write as many tickets as possible, writes tickets even when a person is parked legally. The person can pay it or appeal it, but appealing it is pointless, they are never overturned. Its simply a shakedown of people who park their cars on the streets.