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Public Perception of Safety Messages and Public Service Announcements on Dynamic Message Signs in Rural Areas

Executive Summary

Transportation agencies are frequently asked to post public service announcements (PSAs), such as seat belt laws or announcements concerning upcoming events on dynamic message signs (DMS) when they are not being used for transportation-related purposes. However, there are some concerns that these messages are not understood by travelers and may actually be a distraction. Further, the effectiveness of such messages in influencing motorists' travel behavior and actions (e.g. choice of route, mode, or time of date for travel) is not well understood.

The objective of this project was to assess the effectiveness and potential benefits of posting PSAs in rural areas by surveying frequent and infrequent travelers on those corridors, as well as truck drivers. This project addressed a number of questions related to safety awareness and PSA messages on DMS, including traveler awareness, understanding, changes in behavior, and opinions. Intercept surveys were conducted at rest areas and truck stops to collect public feedback regarding safety messages and PSAs on DMS posted by five agencies in four study corridors.

Analysis was conducted on specific hypotheses for each of the evaluation areas of awareness, understanding, behavior changes and traveler opinions. General and site-specific statistically significant findings from this study show:

  • Awareness: Approximately 77 percent of travelers encountered by the survey team during the screening interview had seen a DMS, while 79 percent of all survey respondents indicated that they had observed at least one of the safety-related messages. Generally, infrequent travelers had higher levels of awareness, followed by frequent travelers, while truckers had the lowest awareness level.
  • Understanding: Over 79 percent of travelers were able to correctly interpret the presented message: in Nevada, truckers were found to have a significantly lower understanding level than infrequent and frequent travelers; in Missouri, infrequent travelers' understanding of the identified message was significantly lower than frequent travelers. An even higher percentage (92 percent) of respondents agreed or strongly agreed that the message displayed in the corridor was understandable; in both Kansas and Nevada, infrequent travelers were more likely than frequent travelers or truckers to consider the message as understandable. Most respondents (96 percent) found messages displayed at other sites to be understandable as well.
  • Behavior changes: Approximately 23 percent of travelers reported changing their driving behavior after seeing the specific posted safety message in the study corridors; however 54 percent of respondents indicated that seeing safety campaign messages on DMSs in the past had caused them to change their driving. While 23 percent of survey respondents reporting behavior changes after reading the specific safety message may seem low, given a generally safe traveling public, e.g., high compliance rates with seatbelt use, this finding is not surprising. Infrequent travelers at most sites were significantly less likely to change their driving behavior because of the safety-related DMS messages. Young travelers and female travelers in Kansas were more likely to change their driving because of the DMS messages. Generally, travelers observing DMS less frequently were less likely to change their driving behavior. The survey data also indicated that the display of a PSA on a DMS is unlikely to cause travelers to slow down to read the message, with 18 percent of respondents reporting that they or drivers around them slow down to read these DMS messages. In Minnesota/Wisconsin and Nevada, infrequent travelers were significantly less likely to respond that the safety-related DMS messages cause them to slow down to read the message than frequent travelers and truckers.
  • Traveler opinions:
    • A high proportion of travelers believed that the specific safety message posted at each survey site was appropriate (90 percent) and raised their awareness of the safety issue (71 percent). The only statistical significant findings for appropriateness were that younger travelers were significantly less likely to consider the messages to be appropriate than older travelers in Kansas, Minnesota/Wisconsin and Missouri, while the opposite was found in Nevada. Regarding raising awareness, the only significant differences were in Kansas where females and travelers seeing DMS frequently were more likely to think the messages raise their awareness of the safety issue.
    • Just six percent of respondents indicated that only traffic-related messages should be shown on DMSs. Impact by traveler type was not statistically significant, but younger travelers tended to be more likely to think the DMS should only display traffic message and these differences were statistically significant in both Kansas and Missouri.
    • Finally, most travelers considered DMS as the best way of communicating safety-related information to the public; significant impacts were only observed in Minnesota/Wisconsin where infrequent travelers had a significantly higher probability of thinking DMS was the best way to communicate safety-related information than truckers.

These study findings provide an understanding of the usefulness and effectiveness of using DMS for safety and PSA campaigns. This analysis supports displaying public service announcements and safety messages on DMS in rural areas given 73 percent of surveyed travelers in rural areas support the use of DMS to display PSAs and safety-related information in general, and 73 percent also think DMS are the best way to communicate that information. Findings validate current agency practices in the survey corridors for displaying safety messages and PSAs on rural DMS.

The findings of this study also suggest that displaying safety messages and PSAs more frequently would not be detrimental. While 23 percent of survey respondents reporting behavior changes after reading the safety message on the DMS may initially seem low, given high compliance rates, e.g., with seatbelt use, this is expected. Even a small percentage of travelers changing their behavior could result in a positive influence on safety, and many responding that they did not change their behavior noted anecdotally that reading the safety message made them more conscious of driving in a safer manner.

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