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Intelligent Transportation Systems (ITS)

Applications of ITS technologies in BRT systems begin with those that are operations-oriented such as 1) fleet management, including automatic vehicle location (AVL) systems, automatic passenger counters, and surveillance systems through the use of remote sensing and close circuit TV, and 2) electronic fare payment systems and passenger-oriented, namely passenger information systems either on-board the bus or at stations/stops. AVL systems automatically determine and track the real-time geospatial location of a bus. Several different technologies may be used to perform AVL, such as GPS, ground-based radio, signpost and odometer, dead-reckoning, and combinations of these. Automatic passenger counters are devices that count passengers automatically as they board and alight transit vehicles, typically buses. Most common technologies include treadle mats or infrared beams. Electronic fare payment systems provide an electronic means of collecting and processing fares. Passengers can use a magnetic stripe card, smart card, or credit card instead of tokens or cash to pay for transit trips. Smart cards have the ability to store monetary value and other information on an embedded integrated circuit or micro-chip.

There are several additional technological systems that may be involved in the implementation of bus rapid transit systems and are at different stages of research, development, and deployment. They include collision warning systems, transit signal priority systems, and vehicle assist and automation systems such as precision docking, automatic steering control systems, and automatic speed and spacing control systems.

Collision Warning Systems

Collision warning systems could augment the driver’s normal driving and could provide alerts to hazards of which he may be unaware, and could also help out in conditions in which the driver is distracted or less than fully alert, e.g., due to fatigue.  Such systems may take the form of forward, rear, and side hazard warnings and can be delivered to the driver by either auditory, haptic, or visual cues. The driver retains responsibility for corrective actions based on the warnings provided. Technologies that may be used in these systems include radar, ultrasound or laser sensors and threat assessment software and the driver interface. Benefit opportunities include a reduced risk of property damage, injuries, and fatalities; reduced liability and vehicle repair expenses; improved vehicle utilization, and improved rider/passenger perception of bus performance. The primary incremental cost generator is for the installation of warning systems on vehicles.

Transit Signal Priority Systems

ITS can help provide priorities for buses at intersections, freeway ramps, toll plazas, and bridge or tunnel approaches. Transit signal priority systems in their simplest form makes it possible for a bus approaching an intersection during the final seconds of the green signal cycle to be detected and to request an extension of the green cycle so that the bus can pass through before the signal turns red, thereby saving the bus and its passengers the red cycle time.  This tends to provide some ancillary time saving benefits to the other vehicles traveling in the same direction as the bus, while increasing the time delays to the crossing traffic. Technologies that may be utilized include vehicle detection, identification, and location systems to identify a bus and communicate to a roadside signal controller cabinet, Global Positioning Systems (GPS), Differential GPS, dead-reckoning for vehicle positioning, and wireless communication. Benefit opportunities include reduced travel time for passengers, higher utilization of the bus fleet, improved schedule adherence (assuming a schedule-based operational policy), and improved service effectiveness in terms of passengers per revenue hour or mile). Incremental cost generators include vehicle and roadside equipment such as vehicle detection systems, signal controllers, and wireless communication systems, and added delays to cross street traffic.

Vehicle Assist and Automation Systems

Vehicle Assist Systems technologies are those that help the driver maintain lateral control of the bus such as Precision Docking and Vehicle Guidance. Vehicle Automation Systems technologies are those that provide both longitudinal and lateral control of the movement of the transit vehicle, for a potentially driverless vehicle or automated section of a route such as Platooning and Automated Vehicle Operations.

Precision Docking Systems
Precision docking systems involves the low-speed positioning of buses relative to the curb or loading platform at bus stops and/or stations under the direct bus driver supervision. The lateral position of the bus is precisely controlled with 1to 2 cm. tolerances. Technologies that may be utilized include roadway magnetic marker sensors or visual/optical sensing systems with an electronically-controlled steering actuator. The benefit opportunities associated with precision docking include reduced bus dwell times, saving times for both passengers and fleer operators; a safer and easier boarding and alighting for handicapped/disabled passengers; less wear and tear on bus tires resulting from scuffing at curbs; reduced level of driver stress; and enhanced comfort for passengers.  Incremental cost generators include electronically-controlled steering actuator, lateral-position sensing system, and reference markings at bus stops/ stations.

Automatic Steering Systems
Automatic steering systems enable buses to stay centered in their traveling lane. Typical technologies include roadway magnetic marker sensors, vision/optical sensing systems with an electronically-controlled steering actuator. Benefit opportunities include the ability to operate buses in narrower lanes, thereby saving rights-of-way (ROW) and construction costs, enabling operations in locations that would be too narrow for conventional buses, a smoother lateral ride quality, and reduced driver stress. Incremental cost generators include electronically-controlled steering actuator, lateral position sensing system, and reference markings along the vehicle lanes.

Automatic Speed and Spacing Control Systems
Automatic speed and spacing control systems have vehicle speed under automatic control rather than under manual or driver control. Vehicles can be operated very close together due to the spacing control. Typical technologies include forward ranging sensors such as radar or laser systems, electronic control of the engine and brakes, and vehicle-to-vehicle data communication systems. Benefit opportunities include an enhanced bus capacity using bus platoons (from close spacing), smooth ride quality for passengers, and a reduction in fuel consumption and level of emissions. Incremental cost generators include sensing and communication devices and electronic brake control actuators.

Authors: Ian McNamara and Mark Miller