

Impairment is impairment and being tired or distracted by phones/technology is often even worse than being intoxicated or high but we tend to love using BAC because it is easy to measure. Locations that legalized weed didn’t have an increase in impaired driving last time I checked, because most people don’t go out driving when they are high while people often drive intoxicated after drinking at bars.
So it didn’t make you dumber. You just didn’t understand that the effects of frequent weed usage takes longer to wear off than alcohol.