Exploratory Advanced Research Program

FHWA White Paper On Mobile Ad Hoc Networks

Appendix B. MANET Use-Cases

FHWA’s EAR Program is currently exploring MANETs and their application to surface transportation. As part of that consideration, FHWA is exploring potential use-cases for MANETs in transportation.

Potential applications for MANETs cross a variety of transportation foci. Operational efficiency management is one of the most common applications of MANETs, as it can encompass a wide variety of simple and complex day-to-day tasks, including traffic management or routing for any mode of transportation. Safety applications of MANETs can be critical in ensuring efficient use of transportation systems to deliver emergency services and security where current infrastructure is lacking. MANETs may have applications specific to urban environments, as well as others most appropriate for rural or remote settings. These use-cases cover the deployment of MANETs as either a primary or secondary communications capacity. The following categories and subsequent use-cases are meant to be examples of potential MANET applications and not exhaustive of existing or nonexisting applications.

1. Operations (Urban): MANETs may be deployed in high traffic density areas with limited cellular signal strength, such as a subterranean interstate highway through a major urban region (e.g., Boston’s “Big Dig” I-93 tunnel). Additionally, there are potential applications in environments featuring viaducts over roadways (i.e., Wacker Drive in Chicago). These types of densely structured and populated urban environments support MANET applications for traffic management, including advanced incident warning, rerouting information, or speed management. In this capacity, MANETs have the potential to expand on connected vehicle infrastructure or vehicle-based pilot deployments (e.g., in New York City) if available. MANETs might also be used to carry multiple video feeds in disaster situations, which could prove beneficial to traffic managers and improving overall situational awareness. MANETs here are not only an extension of fixed communications infrastructure but can serve as a secondary resource for failures in the design of the limited infrastructure or V2V and V2I environments.
   
   
2. Information Sharing/Evacuation: MANETs may be applied for pedestrian wayfinding, routing, tracking, and information sharing in situations with a high density of people but limited radio signal access. Two potential examples include an underground transit station or a large arena or stadium hosting an event with a large crowd. MANETs may be able to interface with existing tactical radios used by first responders and public safety personnel for additional coverage. For each case, MANETs could be both primary and secondary networks that provide routing opportunities for areas that are over capacitated or do not have any network service to begin with.
   
   
3. Intersection Management: MANETs may be applied on crowded and dangerous intersections to protect vulnerable users (e.g., pedestrians and cyclists), with the goal of guaranteeing their safety. In particular, a MANET formed by vehicles and infrastructure installed on the intersection, can prevent accidents by protecting users from potentially dangerous vehicles in an automated fashion. The MANET collaborative localizes and tracks vulnerable users and helps to adjust the speed and trajectories of vehicles based on user positions.
   
   
4. Freight: MANETs may be applied to facilitate movement in high density, multi-modal freight facilities. Through communication between closely coupled nodes in small areas, nodes can route vehicles through these tight or crowded spaces to improve efficiency of freight operations. For example, MANETs could serve as a bridge for maintaining a continuous connection between nodes when there are temporary failures in other primary networks while communicating localization and routing information. MANETs incorporating UAVs for video transmission could provide additional functionality in this application.
   
   
5. Incident Management: MANETs may assist in the location of individual cars and people via mobile devices when cell towers are inaccessible or malfunctioning. This application may be particularly useful in more rural and remote environments that currently experience slower emergency response times.
   
   
6. Operations: MANETs may be used to help coordinate and assemble vehicle platoons, which can result in better fuel economy and reduced congestion. The networks can assist in freight movement and heavy truck platooning along major corridors, which can also result in increased economic benefits.
   
   
7. Mobility/Routing (Rural): The use of MANETs in National Parks or similar areas with limited wireless communications infrastructure may be applied to shuttle services that operate to and within each park. MANETs could assist in the deployment of traditional or automated shuttles and provide important schedule, trip, and other related announcements to the Parks’ users. MANETs could also provide trip scheduling and traveler guidance for areas with limited radio signals.
   
   
8. Mobility/Routing (Urban): The use of MANETs for large-scale events (e.g., Presidential inaugurations, outdoor music festivals, and sporting events) may be applied to transportation services in and around these events. MANETs could assist in the deployment of traditional or automated shuttles and provide important schedule, trip, and other related announcements to event participants.