The influence of hydrophobic windshield coating on driver visual performance
Authors: James R. Sayer, Shinichi Kojima, Michael Sivak, Michael J. Flannagan, Mary Lynn Buonarosa
This experiment evaluated potential benefits of hydrophobic coating of windshields under simulated conditions of use. The main independent variables were hydrophobic treatment, participant age, and time of day. The dependent measures were minimum visual angle resolved and response time. The results indicate that the hydrophobic coating improved visual performance, decreasing the minimum visual angle resolved by almost 34% and reducing the response time by more than one second. In practical terms, visual acuity improved in the treated-nighttime condition to approximately the level of acuity in the untreated-daytime condition. This experiment showed that hydrophobic coatings can result in significantly improved driver visual performance without negatively affecting response time. However, this experiment did not address the durability or longevity of these products, as the hydrophobic coating was only tested when it was newly applied (and therefore could be expected to be near peak performance). Benefits associated with hydrophobic coatings are likely to diminish with time and wear (more or less slowly depending on durability), unless the coating is reapplied.