Elementary my dear man! Let me explain.
1. How will police monitor people who smoke and drive?
Who drives risky when their high? Everyone I smoke with drive really slow when their high, including me.
2. What will be considered "safe" to drive after smoking?
I smoke while I drive..
3. How will they tell how much you have smoked/how impaired you are? (field sobriety tests don't mean shit in court because they are subjective, breathalyzer is the key to conviction for alcohol)
You can't. People can hide their high too well.
4. Can you smoke in public?
5. Can you smoke in a bar?
6. Can you smoke in a car?
7. Can you eat THC products in public?
People already do.
8. Can you be arrested for "high and disorderly"?
Who gets high and challenges cops? Nobody.