Research & Innovation

Need statements

NS730: Use of Colors in Dynamic Message signs for both Travel times and static sign simulation

Problem

MnDOT continues to look for improved methods to provide motorist information that is clear concise and easy to digest. The majority of MnDOT's roadway Dynamic Message Signs (DMS) are capable of full color/full matrix messaging. Finding new ways to display messages that are easier for roadway users to understand will help reduce distractions and increase safety.

All current guidance and regulations reference retroreflective colors for on static signs which look different to the human eyes than light emitted colors. With MnDOT's seat on the NCUTCD committee discussing these standards for the MUTCD, this research could provide clear evidential guidance for future standards. Documenting the differences between retroreflected colors and emitted colors will also help MnDOT provide input to rulemaking that will benefit MnDOT, local agencies, and national agencies as well.

Objective

This proposed research would have two main objectives:

1. Multiple and competing factors affect how MnDOT produces the emitted colors from roadway Dynamic Messaging Signs (DMS). These factors include meeting NEMA TS4 and MUTCD color specifications, producing emitted colors that “match” the retro-reflected colors of static signs, and staying within the capabilities of current LED technology. The link in section ii above shows a graphical representation of these multiple competing affecting DMSs. Having a guide to vet out conflicts and a tool/program (possibly excel) to standardize the process of LED color selection is needed. For example, using the Red, Green, Blue (RGB) color model – the current input for “Purple” used by MnDOT is (110, 38, 123). Is that the optimal color to display “Purple” for the public? MnDOT has found in the past that emitted colors from DMSs need adjustments to match the retroreflective static sign colors.
2. MnDOT would also like to research and document the public’s perception between emitted colors on Dynamic Message Signs and static sign messages. How can we leverage the general public's understanding of web-based travel time map colors to incorporate color based numeric travel time messages on Dynamic Message Signs? Are there ways to improve colors for road user visibility, clarity, etc. Specifically with colors such as “amber”.

Previous research

DMS Color Diagram - https://mndot-lrrb.ideascale.com/a/idea/73588/14007/download

Expected outcomes

• New or improved technical standard, plan, or specification
• New or improved manual, handbook, guidelines, or training
• New or improved business practices, procedure, or process
• New or improved tool or equipment

Expected benefits

The numbers 1 and 2 indicate whether the source of the benefit measurement is from: 

1. A specific research task in your project that supports measuring this particular benefit, or
2. Implementation of the research findings (anticipating positive results)

• Decrease Engineering/Administrative Cost: (2) Improved decision-making processes for MnDOT, local agencies, and national agencies as well.
• Safety: (2) Finding new ways to display messages that are easier for roadway users to understand will help reduce distractions and increase safety.
• User Benefits: (2) Improved DMS colors for road user visibility and clarity. Expanded use of DMS messaging for road user information such as travel time.

Technical advisory panel

• TBD