That jumped out at me, too. That’s rather shocking, isn’t it? Tox screens are used everyday in employment testing, DUI testing, drug testing, you name it. Since when are they not reliable?
An employer only wants to see if you've used weed recently; not whether you're high during the urine test.
Here the prosecutor overcharged the driver, which probably contributed to the acquittal.
It also seems likely that the Detective lied about smelling beer: the toxicology report showed zero alcohol. I would have tossed all the toxicology results for that reason alone- no probable cause, unless the state mandates such testing as part of a vehicle investigation.
As far as witnesses claiming the driver said he tried to beat the train, they may have appeared as reliable as the detective's beer claim.
Maybe the guy did try to beat the train; or, maybe you have an ambitious prosecutor really stretching the charges and the facts to crucify someone to make a name for himself. Hard to tell. In which case, you acquit.