Complaints that the traffic police have exceeded their authority usually result from random stops for the purpose of breath tests and other investigative procedures, which the public often regard as unwarranted infringements of liberty. Other complaints sometimes involve important constitutional issues and are more difficult to resolve. Present laws make it an offense for a person driving a motor vehicle to refuse to stop, proceed, or keep to a particular line of traffic when directed to do so by a police officer who is acting in the execution of police duties. According to recent court decisions, officers can even give directions to a driver to disobey the traffic regulations as long as their duty calls for such action for the protection of life or property. Police officers' powers are not unlimited, however. If officers give directions arbitrarily, capriciously, maliciously, or from personal motives, citizens are not compellable at law to obey. If the officers' actions amount to an interference with subjects' personal liberty or property and are unjustifiable either at common or statutory law, such actions are illegal. Parliament should spell out exactly when disobeying would give rise to prosecution, especially now that new and increased powers concerning the regulation of traffic and encroachment on individual liberty and freedom are being advocated in the interests of crime control and the preservation of law and order. The circumstances surrounding relevant cases are described. A reference list is not included.