The motive force was under the impact: Evidence should clearly show the driving force was impaired, commonly through a blood alcohol focus (BAC) of 0.08% or larger or proof of drug impairment. Felony regulations differ from point out to state, as do prison punishments, but felonies have a hefty penalty: https://dui-lawyers.usattorneys.com/things-you-should-know-if-youre-stopped-for-dui-in-pennsylvania/