Police say the driver was stark naked when they finally stopped him south of Montreal for allegedly running a stop sign and ramming a cop cruiser.
Longueuil police spokesman Mark David says the 23-year-old man could face charges, but for now is in hospital undergoing tests.
They're trying to get a blood sample as the intercepting officers suspect he might have been under the influence of either alcohol or drugs.
David says the man allegedly tried to ram the police car on three occasions but made impact only once, with hardly any damage to the cruiser.
Nobody was injured.