Researchers May Have Found Solution to Windshield Bus GlareFebruary 10th, 2016 by Editor
A team of researchers has solved a problem with windshield glare on bus windshields by using diamond-like (DLC) materials on the glass. Previous research, they say, focused on lighting solutions instead of the glass.
Here’s the issue: During night-time operations, windshield glare caused by interior lighting in a bus can reduce the driver’s vision, creating a dangerous situation.
Enter John Slagter, president, The Mackinac Technology Company in Grand Rapids, Mich., who is working on a Phase II Small Business Innovation Research (SBIR) contract from the U.S Department of Transportation.
“Transit buses operating at night are required to maintain interior illumination whenever passengers are onboard,” he says. “This interior lighting reflects off the windshield and obscures the driver’s vision. The problem of windshield reflection … has not been adequately addressed by industry suppliers,” he says.
Slagter points to recent research at the University of Michigan1 that found interior illumination made it much harder for drivers to see a pedestrian approaching the vehicle.
“We have identified no agency that keeps records of data to quantify the number and severity of accidents attributable to windshield glare, but the hazards presented by reduced visibility are self-evident,” says Slagter. He adds that technical approaches to address this problem have focused almost exclusively on modifications to interior lighting.
“While these approaches may be useful for commercial trucking and passenger vehicle applications, they do not apply to the unique circumstances present on transit buses,” Slagter says. “Regulations require that transit buses must maintain a significant level of interior illumination so that passengers are able to see. This situation does not allow for modifications to interior lighting; it can only be addressed by reducing the light reflectance properties of the windshield itself.”
By using the newly developed diamond-like (DLC) materials, the Mackinac team has achieved what it calls “unprecedented anti-reflection properties on windshield glass.”
Because of its relatively high hardness, DLC is commonly used to improve the durability of glass and other materials, Slagter says. The coating also has anti-fogging properties.
In case you are wondering, he says there is precedent for applying DLC coatings to automotive windshield glass. The Southwest Research Institute (SwRI) has developed a DLC coating that is applied to the windshields of Humvee vehicles and deployed by the Marine Corps in tactical applications.
1 Flannagan, Michael P. and Joel M. Devonshire. “Effects of Automotive Interior Lighting on Driver
Vision.” Leukos 9(1) Jul 2012, pp. 9-23.