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3M Roadway Safety

Safety Initiatives & Funding

New Research Highlights Role of Luminance in Information Acquisition

Have you ever found yourself straining to read a traffic sign that wasn't quite legible? Have you ever missed an exit or a turn because you couldn’t read a sign until it was too late to take safe, appropriate action? Well, researchers at the University of Iowa’s Operator Performance Laboratory set out to study how luminance provided by roadway signage plays a role in how quickly we can process relevant information that tells us which driving tasks are required.

The study, entitled Effect of Luminance on Information Acquisition Time and Accuracy from Traffic Signs, was selected for presentation at the recent 88th Transportation Research Board Annual Meeting in Washington D.C. A link to the full report is included below.

In summary, the study found that:

  • Increasing sign luminance provides faster information transfer from signs to drivers.
  • If viewing time is limited, higher sign luminance and/or larger sign size provides more accurate sign reading.
  • Brighter signs decrease sign reading times and, therefore, are expected to reduce eyes-off-the-road time. Eyes-off-the-road time is the primary characteristic of interest in automotive safety, as driving safety is compromised if one is not watching the road.¹

This research comes at a time when state departments of transportation across the U.S. are looking for ways to improve guide sign visibility and save taxpayer dollars. Many are finding one solution that helps achieve both goals by upgrading to guide signs made with high performance reflective sheeting, while at the same time cutting maintenance and energy costs by turning off guide sign lighting. The Hawaii Department of Transportation is one such agency, having recently replaced signs on the Moanalua Freeway with 3M™ Diamond Grade™ DG3 Reflective Sheeting and eliminated sign lighting. They expect savings of $14,000 per year in electricity and $30,000 in maintenance.

To help demonstrate the benefit of high-performance sheeting in a fun, engaging way, 3M put together a web-based simulator. Go take the today!

¹ Dewar et al. Human Factors in Traffic Safety