1. A method for evaluating the performance of a vehicle windshield wiper mounted in an operational position on a soiled windshield, the method including: capturing a digital image of the surface of the soiled windshield, operating the windshield wiper, capturing a digital image of the surface of the wiped windshield, comparing the data from both captured images to develop selected indicia related to the extent to which the soil has been removed from the windshield.