Yes. A driver is permitted to turn away from or avoid driving through a DUI checkpoint as long as he or she does so in a lawful manner and before actually entering the checkpoint. In the case of Commonwealth v. Scavello, 734 A.2d 386 (Pa. 1999), the Pennsylvania Supreme Court discussed this very issue in a case in which a driver made a lawful U-turn to avoid entering a checkpoint. An officer stopped the driver solely because the driver had turned away from the checkpoint, and the officer discovered that the driver was underage and had been drinking. The driver was ultimately charged with DUI and Underage Drinking. The driver's DUI defense lawyer filed a pretrial motion to suppress evidence and argued that the officer did not have reasonable suspicion that the driver had violated the law and thereby did not have a reason to stop the driver. An unlawful stop would violate the driver's constitutional rights, and the legal remedy is that the court suppresses all evidence found as a result of the illegal detention.
Avoiding a checkpoint is not illegal or indicative of criminal activity
In the Scavello case, the prosecutor raised two arguments. One argument was that people should not legally be permitted to avoid a checkpoint. The second argument was that turning away from a checkpoint should constitute reasonable suspicion of criminal activity to justify a traffic stop. The Pennsylvania Supreme Court rejected both of the Commonwealth's arguments. The Court stated that the police are permitted to stop vehicles without any suspicion of criminal activity IF the vehicle enters the checkpoint, but the lawful authority to conduct a checkpoint does not give the police the authority to stop drivers anywhere else without suspicion of criminal activity. The Court also stated that turning away from a checkpoint is not reasonable suspicion of criminal activity or a violation of the Vehicle Code. Ultimately, the Court held that the officer's stop of the driver violated the driver's constitutional rights and granted the suppression of all evidence.
Traffic Stop Based Upon Suspicion of Violation of Law
It must be emphasized that the driver did not commit any other violations of the law, and the police had no suspicion that he had been involved in any criminal activity. If a person that attempts to avoid a DUI checkpoint commits a violation of the law, the police would now have sufficient cause to conduct a traffic stop. For example, some people approaching a checkpoint fail to use a turn signal when turning around, and some drivers have turned off their headlights to avoid being detected. By failing to use a turn signal or turning off headlights, the driver commits a violation of the law that would justify a traffic stop.
At DUI checkpoints, there is often a police car stationed before the checkpoint that is watching for vehicles to turn around or avoid going through the checkpoint. That officer will often follow a driver that turns away from the checkpoint. The officer is legally permitted to follow a car that avoids the checkpoint, just as the officer is permitted to follow any car on the roadway, but the officer is not permitted to stop the car unless the driver commits a violation of the law. As long as the person drives the speed limit, uses turn signals, and doesn't swerve, the driver can continue on his or her way without being stopped. If the officer observes a vehicle code violation, then the officer is permitted to conduct a traffic stop on the driver.