The investigation was conducted to establish actual driver test conditions which would indicate whether or not any differences in nighttime visibility distances result from a change in the colour and visible light transmittable of the windshield. Drivers were performing under actual roadway conditions with visibility distances measured by a recorder mounted inside the vehicle. The tinted glass used has a visible light transmittance of 71%, measured perpendicular to the surface. Clear glass was employed as a standard which has transmittance of 89%. Results showed great variations in the effect of tinted glass on visibility distances as compared to clear glass. The greater part of the data obtained showed considerable reduction in visibility where the green-tinted glass was used. Its use appears to cause a reduction in visibility distances in night driving. It is recommended that the 70-percent-minimum luminous transmittance requirement for windshields in the American standard safety code be reconsidered.
Abstract