State of the Practice for Traveler Information During Nonrecurring Events

CHAPTER 5. CASE STUDIES

When nonrecurring events cause disruptions to a roadway, from short delays to complete road closures during a peak travel period, it is beneficial to provide road users with information from multiple sources. Travelers may first perform a visual assessment of the situation (e.g., a long line of vehicles approaching an intersection exit ramp or slow-moving vehicles covered with snow and ice proceeding in the opposite direction). Secondary information that they may receive includes roadside DMSs, which can display a limited number of characters in a multi-screen message or an announcement on a terrestrial commercial radio. However, these types of information are typically limited and often nonspecific. Tertiary information generally includes detailed, incident-specific information (e.g., information presented on mobile apps or websites). For example, in an urban area, intended destinations and reliability expectations vary so greatly that road users may desire specific and detailed information, including congestion limits, the condition of alternate routes, and even comparative travel times. This information is too complex and detailed to include on a DMS. Consequently, several media outlets should be used in a coordinated effort to get the necessary information to the user at the right time. For example, a comprehensive system can be coordinated within a mobile app as well as across various components of an ITS system.

In each of the following case studies, the authors examine the use of a medium for providing traveler information as well as its impact in several situations. Delving deeper into a particular medium within a specific context in such a case study approach can provide the audience with useful insights into implementation challenges, as well as useful potential solutions. The examples given below were chosen due to their novel approaches to challenges that other locations may encounter with the hope that they can provide useful lessons learned.

Case Study 1—Mobile Apps

Road user decisionmaking is aided by specific information regarding the nature of the disruption and its anticipated impact. That impact can be expressed in terms of time, restricted access, or distance. For exceptionally complex disruptions, providing immediate information about the impact the disruption will have is sufficient to spur the use of mobile apps and other traveler information systems in making a decision. The user decisionmaking process, which typically assesses the risk of further disruption related to the impact, is generally dictated by the hope of minimizing delays and safety risks by choosing the least disruptive option, which may include proceeding on the planned route.

The ease of access to the Internet by means of mobile cellular devices has revolutionized how the traveling public obtains and interacts with information and the agencies providing it. While traditional traveler information outlets, such as HAR, terrestrial and satellite commercial radio, VMSs, and even variable warning and speed limit signs retain broad application to all travelers, the use of mobile apps enables users to obtain a personalized insight into conditions that can affect their travel.

Numerous agencies, including both State transportation departments and regional transportation agencies, have released mobile apps for traveler information for all modes of transport. Additionally, private sector apps display information concerning congestion levels and even cameras sourced from public agency data.

Apps from MnDOT, the Georgia Department of Transportation, and WSDOT (see figure 5 ) allow immediate access to camera images from roadside surveillance systems, integration with information from mapping services to view traffic conditions, and the ability to instantly learn about the nature and duration of incidents reported in the app.^{(22 ,42 ,26)} These incidents can include a variety of disruptions, such as sporting events, parades, traveling dignitaries, transient road work, and crashes.

In Washington, due to the complexity of the transportation network, an effort was made to incorporate a variety of traveler information systems, even across modes, into a single source. In addition to roadway travel information, WSDOT provides information on the ferry system (used by walk-on passengers)—the largest in the United States—and provides the ability to make vehicle reservations using a mobile-optimized external site. It also provides information on the Amtrak Cascades® intercity regional rail service. Additionally, WSDOT uses the app interface as a platform for its efforts to disseminate information using social media.^{(26 )} WSDOT has made extensive use of Facebook® and Twitter™, particularly with regard to reporting incidents and the progress associated with clearing those incidents. WSDOT’s Twitter™ feed is also used to advise road users of incidents related to snow removal, avalanche control, large gatherings such as sporting events, and weather-related road conditions. Oftentimes, the social media messages include photographs that provide a comprehensive overview of what to expect, which is of great use to users. For example, photographs of a flooded roadway with submerged vehicles are a much greater deterrent than a DMS with a message regarding roadway flooding ahead.

The WSDOT app also features a traffic map, with mapping and congestion information sourced from Google®.⁽²⁶⁾ Through the map, users can view nearly live camera images from throughout the State, including a video feed in select locations. Information on the mountain passes, including current weather conditions, traffic restrictions, and planned closures, is also disseminated (see figure 6 ). It is key information for east-west commerce in the State, particularly for freight. WSDOT’s rural ITS infrastructure such as the sign on I-90 over Snoqualmie Pass (see figure 7 ), correlates with the information disseminated using the mobile app and social media, ensuring consistency in messaging.

The MN 511 app focuses on urban freeway traffic conditions and rural roadway status.⁽²²⁾ It also provides still shots from camera feeds for the entire State. The flexibility of the MN 511 mobile app and users’ abilities to turn layers on and off allows them to obtain information specific to the disruption in question. Simplification of the user interface (see figure 8 ) with easy-to-understand layer control allows users to add information until the desired detail is reached so that they can make a decision at the earliest possible and least complex stage of the interface. The app also allows users to toggle different layers to customize the details shown (see figure 9 ).

Bridge and toll road authorities as well as county-level transportation departments are producing apps to provide traveler information. The Lake County PASSAGE app (see figure 10 ), which was produced by the same department within Lake County PASSAGE that manages traffic signal operations in Lake County, IL, provides an interactive map that prioritizes traffic incidents and road work.^{(45 )} That app as well as another produced by the Virginia Department of Transportation (VDOT) also provide a textual means of accessing information on incidents through an incident list and Twitter™ feed, respectively.⁽⁴⁶⁾

Case Study 2—Comprehensive Rural ITS

In areas where cellular network coverage is problematic and/or driver distraction can lead to high-speed crashes, such as rural freeway networks, providing users with easy access to critical information is a primary concern for agencies. This case study describes one such example in Wyoming. It was recognized that rural traveler information was a means of ensuring public safety and possibly saving lives. As such, the State sought to develop a rural ITS network to support weather-related traveler information systems covering primary highways throughout the State. It developed its Weather Responsive Traffic Management System, which receives data from weather stations and condition reports from maintenance employees using a mobile app hosted on a tablet.

The Wyoming system disseminates information to users primarily through the rural ITS infrastructure in direct and indirect methods. The rural DMS system is used to advise of road closures, inclement weather, and speed reductions by providing direct information to the motoring public. The variable speed limit systems on I-80 and State Highway 28 provide indirect information, an implicit indication of hazardous conditions by means of a reduced speed limit. In most cases, traffic volumes are low enough that users can calculate the extent of the impact of the weather-related disruption by simply adjusting their arrival time expectation based on the revised speed limit. While inferred, the adjustment in speed indicates both the nature of the incident (visible to the user) and the impact (a reduction in expected travel speed, leading to a later arrival).

Typical rural ITS apps tend to focus more on hazards due to nonrecurring conditions and less on disruptions due to incidents related to those conditions. As noted in chapter 2, when a decisionmaker is in a potentially stressful situation (e.g., a dangerous weather event), that person is less capable of handling complex tasks (including making calculations or logical inferences). Therefore, providing clear, direct, and concise information is preferred.