Color dynamic message signs (DMS) have significant benefits over traditional single-color (amber) DMSs. Two of these benefits are: increased ease of message recognition and the ability to convey additional information using pictures that traditionally cannot be conveyed due to space restrictions.
In another study by the University of Rhode Island, titled Employing Graphics to Aid Message Display on Dynamic Message Signs, researchers found that motorists show a definite preference for messages using graphics compliant with FHWA’s Manual on Uniform Traffic Control Devices (MUTCD) over those that contain only text. As a part of this study, participants viewed simulated video of messages from a motorist’s point of view. In this test, participants identified the content of a message with only text in an average of 20 seconds, while a message with a graphic took an average of 14 seconds. This indicates that the color DMS allows motorists to comprehend messages sooner and allows them to focus more on the roadway, hence increasing safety.
Color DMSs allow operators at transportation management centers (TMC) to format DMS messages differently by adding graphics. For example, when displaying travel times, TMC staff can use roadway shields to represent the current roadway and the travel time to a destination.
In order to display graphics on DMSs, color resolution is critical. Color resolution was not crucial with single-color DMSs as they only displayed text. However, with graphics on DMSs, the resolution plays a significant role in the type of DMS used. One of the common images displayed on the DMS is the roadway shield. It is important to ensure that the DMS resolution is sufficient to capture details on the shield. If the DMS resolution is not high enough, the image will not be easy to discern and could result in the driver spending more time to understand the information being conveyed through the graphics.
SunGuide® software, Florida's statewide advanced traffic management software, has been modified to support color DMS. One of the key modifications is software compliance with the most recent version of National Transportation Communications for ITS Protocol (NTCIP). The software also supports creating templates for commonly occurring event types so that TMC staff do not have to design messages for each event. This helps to disseminate information quicker and save time.
The Florida Department of Transportation (FDOT) has been deploying intelligent transportation systems for several years and some of the DMSs are reaching end-of-life. FDOT will have to replace the existing DMSs and the color DMS will be an alternative for consideration. A few regions in Florida, including Orlando, Fort Lauderdale, and Miami are deploying color DMS.
This article was provided by Brian Ritchson, FDOT Traffic Engineering and Operations Office.
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