National Academies Releases Nighttime Overhead Signage Luminance Levels

The National Academies Press has issued an 80-page report entitled “Guidelines for Nighttime Overhead Sign Visibility.” It includes a chart that’s headlined “Luminance Levels for Overhead Signs.” It lists five different visual complexity levels, ranging from a dark rural area to a commercial downtown district. It then suggests minimum luminance levels in terms of candelas per square foot and square meter. The suggested brightness levels at the most complex setting are 10 times higher than for the rural setting.

You can download the entire report at https://www.nap.edu/download/23512

Texas/Pennsylvania DOT Studies Says Clearview Font Improves Sign Legibility

A study conducted jointly by the Texas and Pennsylvania Departments of Transportation concluded that the Clearview font increased the visibility distance for drives by 12% versus the existing Series E Modified font.

In 1994 the Federal Highway Administration determined that highway signs were no longer visible enough for a population that included older drivers. Over the next decade, the Clearview font was developed. Subsequently, the Texas and Pennsylvania DOTs conducted separate studies to see how effective the Clearview font was.

The full report on this font can be found at http://onlinepubs.trb.org/onlinepubs/trnews/trnews243RPO.pdf