My friend got pulled over for dui but not drinking but they found alot of mary jane and now he wants his doctor to prescribe it so he wont get in trouble and he gonna say for migrains maybe the world biggest itiot? !

Lets say I smoke mary jane 4 days ago and I get pulled over. Could I be charged with a DUI even if I smoked 4 days ago?

Lets say I smoke mary jane 4 days ago and I get pulled over. Could I be charged with a DUI even if I smoked 4 days ago? I would not be high at the time, but I still had it in my system.