Two types of formulations define drunk driving: the 'intoxication' and 'per se' standards. The traditional statute requires proof of DWI, a vague standard that puts de facto power both in the hands of the police officer who makes the arrest and administers the field sobriety test and in the hands of the judge or jury which applies the vague standard. Moreover, the elements of the offense have not been clearly defined in most jurisdictions. Most courts treat drunk driving as a strict-liability offense, leaving no escape for defendants whose intoxication was inadvertent and even 'reasonable.' The modern per se offense is even more questionable than traditional DWI. It is a prophylactic-type criminal law that imposes strict liability regardless of subjective culpability or manifest dangerousness. A driver who was operating a vehicle flawlessly and who could pass a field sobriety test would still be guilty of drunk driving if a breath test showed the driver's blood alcohol content to be 0.10 or greater.