What must be functional for the windshield wipers to pass inspection?

For a vehicle to pass inspection in Pennsylvania, both wiper blades must effectively clear the windshield. This is essential because the primary function of windshield wipers is to maintain visibility by removing rain, snow, and debris from the glass. If both wiper blades do not operate properly, it could create dangerous driving conditions due to reduced visibility during inclement weather. This criterion ensures that drivers can safely operate their vehicles in all weather conditions, thereby enhancing overall road safety.

While having at least one wiper blade operational or ensuring the wiper fluid is filled is helpful, they do not meet the requirement necessary for a passing inspection. Additionally, while worn wipers may require maintenance, the focus during inspection is primarily on their operational effectiveness. Thus, the requirement is for both blades to work efficiently to clear the windshield, ensuring safety for the driver and others on the road.