I know it varies depending on the nature of the offence but I have in mind things such as jumping traffic lights, obstruction or speeding.
I ask because I was nearly arrested by a cop near Wilson Airport who apparently mistook my car for another one he'd seen take a wrong turn. Thank goodness my passenger still had a speck of fresh Ugali on his arm and he produced it as evidence of the fact that we'd been parked a long time enjoying our lunch and had no clue what the officer was talking about.
So, what if he'd been adamant and insisted it was me he saw and took me to court. How would he prove my culpability? What if you are accused (rightly or wrongly it doesn't matter) of jumping traffic lights or speeding and you're taken to court and you deny it, what sort of evidence would the arresting officer have to table to have you convicted?
Learn first to treat your time as you would your money, then treat your money as you do your time.