Intelligent Transportation System (ITS)
The 1939-40 New York World’s Fair envisioned automated vehicles with radio controls to help them maintain a proper distance apart. By the 1980s, “intelligent vehicle highway system (IVHS)” arose to describe how computers could connect vehicles to infrastructure. In 1994 the national IVHS program was renamed the Intelligent Transportation Systems Joint Program Office (ITS-JPO) and started working on a national systems architecture and standards.
Today, the USDOT’s ITS Strategic Plan centers on implementing connected vehicle (CV) technology and advancing autonomous vehicles (AV). CV and AV are different technologies that can work cooperatively. Limited deployment has begun and is expected to become widespread over the next 10 years to 20 years.
Connected vehicle (CV) technology
Wireless communications among vehicles, infrastructure, and personal devices operated by passengers, pedestrians, bicyclists, and other road users. Relies on vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) connectivity.
Wireless communications maintain 360-degree awareness of position, direction, and speed of nearby vehicles. Cars, trucks, and buses share safety and mobility information to notify drivers of dangerous situations, such as an oncoming car out of sight beyond a curve.
Wireless exchange of data between vehicles and infrastructure assets such as signals, signs, toll booths, work or school zones, and railroad crossings. Data from these assets is delivered to the vehicle and data from the vehicle is delivered to the assets.
Roadside Unit (RSU)
Computing device within road infrastructure that provides connectivity support to passing vehicles.
On Board Unit (OBU)
Computing device in the vehicle that interfaces with RSUs and other OBUs to acquire information about traffic and road conditions.
Dedicated Short-Range Communications (DSRC)
While wireless technologies such as cellular networks and WiFi can support a range of CV operations, communication flows will be based primarily on DSRC. This networking technology gives vehicles 360-degree awareness of conditions, nearby vehicles, and hazards at up to 1,000 feet; and is considered the next-generation technology in crash prevention.
DSRC is fast, secure, reliable, and invulnerable to interference, according to a U.S. DOT Fact Sheet.
The CV environment that’s taking hold depends on access to the 5.9 GHz wireless spectrum without fear of interference that could interrupt service and restrict the reception of safety-critical communications. To ensure this access, the Federal Communications Commission allocated 75 MHz of spectrum in the 5.9 GHz band for use by ITS vehicle safety and mobility applications. 5.9 GHz dedication ensures that when a vehicle needs access to the spectrum, the spectrum is available.
Automated Vehicles (AVs), aka “self-driving cars”
According to ITS-JPO, automated vehicles (AVs) operate at least some aspect of a safety-critical control function (steering, throttle, or braking) without driver input. AVs may use only OBUs or may also be connected (use communications systems such as CV technology). Vehicle connectivity is important to realizing the full potential benefits of AVs.
In September 2016, U.S. DOT adopted automation levels identified in SAE Standard J3016: Taxonomy and Definitions for Terms Related to On-Road Motor Vehicle Automated Driving Systems.
Level 0: Driver does everything.
Level 1: System helps with some tasks (adaptive cruise control).
Level 2: System does some tasks while driver monitors environment and does other tasks (combined lane centering).
Level 3: System does some tasks and monitors environment but driver must be ready to resume control.
Level 4: System drives and monitors environment under certain conditions; driver needn’t resume control.
Level 5: System performs all tasks under all conditions; no human intervention required.