Background and Objectives: The effects of chronic sundamage including telangiectasias, solar lentigos, rhytides, enlarged pores, sagging skin and pre-cancerous and cancerous growths are among the most common presenting complaints in a dermatologist's office. These changes are often worse on the driver's side of the face, emphasizing the role of UVA exposure received while driving in producing these changes. This study was undertaken to measure the ability of car window glass alone and in combination with UV-absorbing film to reduce UV-damage as measured using an established in vitro model of phototoxicity. Study Design/Materials and Methods: Using the 3T3 neutral red uptake photoprotection assay with solar simulating radiation administered by a xenon arc solar simulator, we measured the photoprotection ability of auto glass, window film that filters ultraviolet radiation, and the combination of window film and auto glass. Results: Auto glass reduced cell death from solar simulating radiation by 29%, while window film afforded 90% protection, and the combination of auto glass and film reduced cell death by 93%, when compared to unfiltered solar simulating radiation. Conclusions: Window film that filters ultraviolet radiation results in dramatic reductions in cytotoxicity when measured by the neutral red uptake photoprotection assay. Widespread use of window film provides an ever-present barrier to ultraviolet A exposure and could potentially reduced the detrimental effects of ultraviolet A, including photoaging, skin cancer and ocular damage such as cataracts. In addition, such film is essential for patients suffering from conditions sensitive to ultraviolet radiation, such as lupus erythematosis.