Windshield wiper arms should be adjusted in this position.

The optimal position for windshield wiper arms is down, as this allows them to effectively clear water and debris from the windshield when in operation. When the wipers are in the down position, they make full contact with the glass, ensuring a thorough clean and enhancing visibility for the driver. This also helps to prevent damage to the wiper blades, as they are protected from exposure when not in use.

In addition, having the wiper arms in a down position can reduce wind resistance when the vehicle is in motion, which may prolong the life of the blades. This adjustment is crucial for maintaining proper functionality and performance of the windshield wipers, ultimately contributing to overall safety while driving.