Your windshield wipers are responsible for cleaning a viewable area on your windshield. They swipe back and forth to remove rain, snow, ice, dirt, and other debris. Their primary purpose is to ensure that the driver is able to see as much of the road and surrounding traffic as possible.
Clear visibility is accomplished by offsetting the wiper blade pivots. When you look at your windshield, your windshield wiper pivots are not centered on the glass. They are both set further left, with the passenger side wiper being close to the middle of the windshield. When the wipers are engaged, they swipe upward, then stop and reverse when they reach a position just past vertical. The driver’s side wiper blade is just long enough that it doesn’t contact the top windshield molding or edge of the glass. The passenger side wiper blade gets as close to the passenger side of the windshield glass as possible to clear the most area.
In order to achieve the maximum space cleared, wiper blades are typically two different sizes depending on exactly where the wiper pivots are positioned. In some designs, the driver’s side is the longer blade and the passenger side is the shorter blade, and in other designs, it is reversed.
If you replace your wiper blades, make sure to use the same size as indicated by your car manufacturer to get the best viewing area for the driver.
