National Academies Press: OpenBook

Low-Speed Automated Vehicles (LSAVs) in Public Transportation (2021)

Chapter: Chapter 2 - Use Cases and Operational Design Domains for LSAVs

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Suggested Citation:"Chapter 2 - Use Cases and Operational Design Domains for LSAVs." National Academies of Sciences, Engineering, and Medicine. 2021. Low-Speed Automated Vehicles (LSAVs) in Public Transportation. Washington, DC: The National Academies Press. doi: 10.17226/26056.
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Suggested Citation:"Chapter 2 - Use Cases and Operational Design Domains for LSAVs." National Academies of Sciences, Engineering, and Medicine. 2021. Low-Speed Automated Vehicles (LSAVs) in Public Transportation. Washington, DC: The National Academies Press. doi: 10.17226/26056.
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Suggested Citation:"Chapter 2 - Use Cases and Operational Design Domains for LSAVs." National Academies of Sciences, Engineering, and Medicine. 2021. Low-Speed Automated Vehicles (LSAVs) in Public Transportation. Washington, DC: The National Academies Press. doi: 10.17226/26056.
×
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Suggested Citation:"Chapter 2 - Use Cases and Operational Design Domains for LSAVs." National Academies of Sciences, Engineering, and Medicine. 2021. Low-Speed Automated Vehicles (LSAVs) in Public Transportation. Washington, DC: The National Academies Press. doi: 10.17226/26056.
×
Page 11
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Suggested Citation:"Chapter 2 - Use Cases and Operational Design Domains for LSAVs." National Academies of Sciences, Engineering, and Medicine. 2021. Low-Speed Automated Vehicles (LSAVs) in Public Transportation. Washington, DC: The National Academies Press. doi: 10.17226/26056.
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Page 12

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8 This section focuses on use cases and operational design domains for LSAVs. The discussion on use cases describes the service models and transportation needs LSAVs address, both now and in the future. LSAV operational design domain (ODD) attributes are relevant to how both conventional and automated vehicles can operate with various road conditions, speed, weather, and other factors. For automated vehicles, such as LSAVs, the ODD is defined as either “limited” or “unlimited” under the SAE taxonomy.5 ODDs suitable for LSAVs vary according to the vehicle; environmental, geographical, and time-of-day restrictions; and the requisite presence or absence of certain traffic or roadway characteristics. 2.1 LSAV Use Cases LSAV services may be provided by public transportation agencies, connect to public transit, or provide shared mobility services in areas with no or limited public transportation. Many examples of LSAV services presented in this report are currently being planned and implemented by public and private organizations that do not provide public transportation. The use cases for LSAVs include two aspects of the services: • Service models. The service models include fixed routes, circulators, shuttles, first mile/last mile feeder services, and paratransit and other on-demand mobility options. These models may be combined. For example, a service may operate along a fixed route where pick-up is on demand and may use a flex zone surrounding the fixed route to expand the locations served. Some service models may operate as prearranged, zone-based, or property-based services. The various service models may also operate flexibly, meaning they could change on the basis of customer requests. • Trip purposes. LSAV services for specific types of trips are being planned and piloted by orga- nizations that are not public transit providers. These include services for health care, employ- ment, entertainment, recreation, retail, parking access, residential development, and senior social services. In the future, public transit agencies, as well as other public and private provid- ers, may offer LSAV service to provide general mobility for any trip in the public right-of-way. As will be discussed in Chapter 4, LSAV services operated by public transit agencies and funded by the federal government must be ADA compliant and accessible to disabled persons. C H A P T E R 2 Use Cases and Operational Design Domains for LSAVs 5 SAE International, “Taxonomy and Definitions for Terms Related to Driving Automation Systems for On-Road Motor Vehicles,” Document J3016, issued January 2014, revised June 2018.

Use Cases and Operational Design Domains for LSAVs 9 LSAV Service Models The following LSAV service models may be offered by public transit agencies or other public and private providers. The first four models generally operate as fixed services. LSAV service models may be provided areawide or on a zoned basis. They could be more flexible than tradi- tional on-call services in both routing and employing mobility-on-demand options and using smartphone apps, automated kiosks, or web-based bookings. This flexibility allows passengers to request pick-up and drop-off to desired destinations or door-to-door service. Fixed-route LSAV services operate on a set path between end points with stops along the way, similar to traditional public transportation provided by bus or rail services. Vehicles may travel at different speeds in dedicated lanes or in mixed traffic. Fixed-route LSAV services can stop at all programmed points or by request. Vendors are introducing voice-activated technology, computer screens, call buttons, and other mobile device applications to allow customers to request stops from inside LSAVs. The frequency of trips or the size of vehicles can be altered to match demand. Circulators operate within a closed loop, usually 3 mi or shorter. LSAV circulator services are particularly appropriate where people travel within a specific neighborhood or campus. In existing public transportation circulator services, stops are often closer than in fixed-route service, given the proximity of destinations in the area. Because ridership is high density and the service may represent only one leg of a multimodal trip, conventional circulator services often operate more frequently, and vehicles can be smaller. A–B shuttles travel between two points, either on a fixed route or as a circulator. For example, an A–B LSAV shuttle could travel to and from a special event, employment destination, or parking lot. A–B LSAV services may include the capability for customers to request on-demand stops within or outside the vehicle. First/last mile and feeder services connect customers to higher-capacity fixed-route rail or bus public transit services. The effect is to increase the catchment area of a bus stop or rail station. Typi- cally, first/last mile services make short-distance trips and may run all day or just during morning and evening peak hours. First/last mile LSAV services may operate as fixed routes but could deviate to provide flexible routes and door-to-door service. Small LSAVs could offer frequent service from a transit stop or station and nearby destinations. Paratransit (on-demand service) LSAVs may provide point-to-point services by customer request, which could be especially beneficial to customers with mobility, visual, or communica- tions disabilities who need door-to-door services. These services, which may be either booked or provided on demand as driverless taxis or ride-hailing services, could be deployed as shared services that pool people headed in the same direction into one vehicle. LSAVs—whether as para- transit or general access—could be dispatched when a threshold number of people or specified wait time is reached. LSAV Trip Purposes Served Most LSAV services for specific-purpose trips are being planned and tested by organizations that are not public transit providers. Instead, these services are typically provided by public and private organizations that may interface with public transit providers (Table 2.1). Examples of trip purposes being served by LSAVs or being considered for future LSAV services include • Education. LSAVs can provide connections to and within university and other educational campuses, expanding both mobility options and educational opportunities.

10 Low-Speed Automated Vehicles (LSAVs) in Public Transportation LSAV Project Example Trip Type Service Model Jacksonville, Florida Education Fixed Routes, Circulators, A–B Shuttles, Prearranged Route, or Zone-Based Services Grand Rapids, Michigan Health Care Circulators Youngstown, Ohio Education, Employment, Entertainment, Health Care Circulators Frisco, Texas Employment, Entertainment Circulators Arlington, Texas Education, Employment, Entertainment, Recreation, Retail, Parking Fixed Routes, Circulators, Paratransit Doraville, Georgia Entertainment, Recreation, Retail Circulators Detroit, Michigan Bedrock Parking Circulators Ann Arbor, Michigan Mcity Education A–B Shuttles Las Vegas, Nevada GoMed Employment, Health Care A–B Shuttles Pawtucket and Providence, Rhode Island Employment Fixed Routes, First/Last Mile The Villages Florida and California Recreation, Health Care Paratransit, On-Demand Pooled Services Table 2.1. LSAV project use cases.

Use Cases and Operational Design Domains for LSAVs 11 • Employment. LSAVs can provide access to employment centers and allow mobility within such a center. (An employment center is an area where job locations are concentrated, such as an office park, downtown, mixed-use campus, industrial park, or cluster of office buildings.) Such services may decrease parking requirements and increase amenities for employees and visitors. • Entertainment, recreation, and retail. LSAVs can connect customers to entertainment, recreation, and retail venues, as well as allow movement within a defined single-purpose or mixed-use district. LSAV services can help reduce parking requirements and improve acces- sibility, particularly for those with a mobility, visual, or cognitive impairment. • Health care. LSAVs can provide service to and within a health care campus, or point-to- point service to medical and behavioral health services, to improve access to health care. LSAV services may decrease transportation time to appointments, reduce parking requirements, and increase rates of follow-up care. • Parking. LSAV can shuttle employees to and from remote parking, reducing parking costs for employees and employers. • Property-based services. Real estate developers often fund property-based services to attract shoppers or to provide amenities for employees or residents. LSAV services such as circula- tors and first/last mile services can connect residents, customers, and employees to home, shopping, and work. • Senior services and residential developments. LSAVs can provide seniors fixed-route and on-demand services within campus environments and to community and human services. 2.2 Operational Design Domains The ODD for LSAVs or any automated vehicle is the operating conditions under which a given driving automation system or feature is specifically designed to function. Conditions include, but are not limited to, environmental, geographical, and time-of-day restrictions, and the requisite presence or absence of certain traffic or roadway characteristics. Key ODD attributes for practi- tioners to consider include posted and operational speeds, intersections and crossings, and road conditions. The following are key aspects of ODDs related to LSAVs: • Vehicle speed. As the name “low-speed automated vehicles” suggests, speed is a key consider- ation in assessing whether an LSAV may operate in a specific environment. Practitioners must account for posted and operational speed. “Operational speed” refers to the speed of other vehicles in mixed traffic in the same right-of-way. LSAVs’ operating environments typically have posted speeds of under 35 mph. • Traffic, roadway characteristics, and roadway conditions. Depending on their specific design, LSAVs can travel in mixed traffic with a range of crossings (e.g., unprotected turns, controlled stops, and signalized intersections). On the basis of a given LSAV’s capabilities and the nature of a potentially hazardous intersection, an operator, vendor, or transportation agency may add sensors at an intersection to enhance vehicle-to-vehicle and vehicle-to-infrastructure commu- nication. Adding fixed sensors to augment the LSAV environmental data may be especially important for unprotected left-hand turns. A signal may be phased, or a signal phase can be communicated from the LSAVs automatically. (At this time, safety operators are sometimes directed to revert to manual mode for left-hand turns.) • Weather. As another key factor for providers deploying LSAVs, weather conditions that can have adverse impacts include heat, snow, and rain. The effect depends both on the intensity of the weather condition and the specific design of the vehicle. A summary of ODD attributes pertaining to LSAVs’ interactions with other road users, crossings, and turns is presented in Table 2.2.

12 Low-Speed Automated Vehicles (LSAVs) in Public Transportation Operational Design Domain Description/Significance Example Pilot or Demonstration “Level of interaction with other road users” (or “right-of-way”) determines the complexity of the operational environment for an automated vehicle. Right-of-way that minimizes interaction with other vehicles and pedestrians is generally easier to automate, given simpler programming parameters and less chance of an unexpected edge case scenario. Exclusive off-street guideway Operates in dedicated guideway or path and may be governed by geofencing or physical infrastructure Jacksonville Ultimate Urban Circulator (U2C) Off-street multiuse pathway No light duty vehicle traffic; pedestrians, cyclists, and scooters present Arlington (Texas) Milo shuttle On-street pathway with dedicated lane for LSAVs Dedicated lane, although on a street/right-of- way with other traffic in other lanes and no physical barrier Jacksonville Bay Street Corridor On-street pathway with dedicated lane for LSAVs and other transit vehicles On-street mixed traffic Right-of-way/street in mixed traffic Bedrock Detroit shuttle Drive AI, Arlington (Texas) “Crossings/turns” refers to how the route of the vehicle crosses other vehicles’ paths. Unprotected left-hand turns Vehicle must cross pathway of other vehicles Dedicated to specific types of vehicles and transit Tampa downtown shuttle Table 2.2. Key ODD considerations for LSAVs.

Next: Chapter 3 - LSAV Projects »
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Interest in driverless vehicles, including low-speed automated vehicles (LSAVs), continues to expand globally and in the United States.

The TRB Transit Cooperative Research Program's TCRP Research Report 220: Low-Speed Automated Vehicles (LSAVs) in Public Transportation presents current use cases for LSAVs and provides a practitioner guide for planning and implementing LSAV services as a new public transportation service.

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