If people want to stay on the right side of the law, they should consider not driving at all when high. I know that can be inconvenient, but it isn't unreasonable. Rather than trying to determine exactly how much or little cannabis you can consume and remain under the legal limit, choose not to get behind the wheel. My advice w/r/t alcohol and other drugs is identical.

As for the per se standard, I think it would be a great idea for drivers under 21. I'm not opposed to a universal standard in principle, but I question whether it is needed. I would welcome increased police efforts to stop and arrest high drivers, with or without this bill.