U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590

Skip to content
Facebook iconYouTube iconTwitter iconFlickr iconLinkedInInstagram

Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations

This report is an archived publication and may contain dated technical, contact, and link information
Back to Publication List        
Publication Number:  FHWA-HRT-17-014    Date:  April 2018
Publication Number: FHWA-HRT-17-014
Date: April 2018


State of the Practice for Traveler Information During Nonrecurring Events


Background and Objectives

Incident-related and other nonrecurring congestion are major contributors to total congestion delays on highways. For example, it has been estimated that roughly half of all delays on freeways in the United States are due to nonrecurring causes.(7) Types of nonrecurring events may include traffic incidents, severe weather, work zones, emergencies, and sporting events. Devices and media that can be used to convey information about nonrecurring events to travelers may include mobile apps, changeable message signs (CMSs), telephony, websites, radio, and in-vehicle devices that may become part of the connected vehicle ecosystem. It is important to review outcomes from a traveler’s perspective regarding access to, perception of, and need for traveler information surrounding nonrecurring events. It is also essential to take into consideration that in order for information for nonrecurring events to be optimally presented, it must match user needs in both content and media. Examination of the ever-expanding role of the private sector in existing and future real-time advanced traveler information systems (ATISs) were also considered throughout.

The purpose of this task order was to identify and comprehensively review literature and synthesize best practices on efforts to understand travelers’ information needs and related decisionmaking processes within the context of nonrecurring events. The ultimate goal was to find what information will help the traveling public make the most effective and safest travel decisions during nonrecurring events.

This report presents a comprehensive review that is up to date and easily accessible for use with present-day challenges while also being forward-looking for upcoming trends and advances as the landscape of nonrecurring events information evolves. This review emphasizes clarity, relevance, and ease of use for a wide range of potential users. It can be used as a tool to understand how to anticipate and adapt to user needs and decisionmaking processes in a range of nonrecurring event situations. Information about nonrecurring events had traditionally been investigated from the perspective of agency dissemination practices and considered a limited range of situations. The best dissemination practices, however, must also account for the audience and needs of the public.


The research effort began with keyword searches of relevant databases with an emphasis on recent information.(8) To be fully comprehensive, the review also included information gathered from international sources.(9 ,10) Each search included a combination of keywords as well as supplemental keywords used to refine search results. The following five main search categories were created to encompass the key project dimensions, as outlined in the statement of work: (1) core concept, (2) data and technology, (3) location, (4) specific technologies, and (5) supplementary terms. Using these categories, a list of search terms was then compiled and organized appropriately. As an example, the search terms “traveler information” and “incident” were both placed in the core concept category. The following list shows an initial sample set of search terms organized by the five key search categories:

Additional search terms were added and adjusted for follow-up searches.

Boolean logic was applied to further define the search. Search terms from the five categories were combined with Boolean operators (AND, OR, etc.) to exclude irrelevant literature and limit results to within the project scope. For example, in an initial search, terms from the core concept, location, data and technology, and specific technologies categories were combined in a way that would return literature containing any of the keywords in any of the categories. Due to search character limits, this Boolean combination can be divided into a series of searches as follows:

Note that the asterisk represents a “wildcard” character. In anticipation of these search terms returning thousands of documents, in each case, the first 100 search results were carefully screened. Relevant literature was identified, as defined by the project dimensions and the statement of work. Additionally the following avenues were reviewed:

Once key sources were identified, they were analyzed in terms of the following:

Organization of Report

The remainder of the report is organized into the following chapters:



Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000
Turner-Fairbank Highway Research Center | 6300 Georgetown Pike | McLean, VA | 22101