🚗AutoPilotWatch

Autonomous Vehicle Glossary

51 key terms and acronyms used in autonomous vehicle safety reporting, regulation, and technology.

💡 Understanding the Language of AV Safety

SAE Levels

Driving automation is classified into 6 levels (0-5) by SAE International. Most current systems are Level 2 (ADAS) or Level 4 (ADS).

Sensor Types

Cameras, lidar, radar, and ultrasonic sensors each play different roles in how autonomous vehicles perceive the world around them.

Regulatory Terms

SGO, NHTSA, ODI, CBI — understanding regulatory acronyms is essential for interpreting AV safety data.

ABCDEFGHILMNOPRSTUVW

A

ADAS
Advanced Driver Assistance Systems. SAE Level 1–2 systems that assist the driver but require constant human oversight. Examples include Tesla Autopilot, GM Super Cruise, and Subaru EyeSight.
ADS
Automated Driving System. SAE Level 3–5 systems capable of performing the entire Dynamic Driving Task without human intervention within their Operational Design Domain. Examples: Waymo Driver, Cruise AV.
Autopilot
Tesla's branded Level 2 ADAS suite comprising Traffic-Aware Cruise Control and Autosteer. Despite the name, it requires active driver supervision at all times. Involved in 3,092 NHTSA-reported incidents.
AEB
Automatic Emergency Braking. A safety system that detects an imminent collision and automatically applies the brakes if the driver fails to respond. Required on all new U.S. vehicles starting in 2029. AEB is a foundational ADAS feature that often works alongside more advanced systems like Autopilot.

B

BlueCruise
Ford's hands-free Level 2 ADAS system for divided highways. Uses driver-facing cameras to monitor attention. Available on select F-150, Mustang Mach-E, and Lincoln models.

C

Camera-only
An autonomous driving sensor strategy that relies exclusively on optical cameras for perception, without lidar or radar. Tesla is the primary proponent of this approach ("Tesla Vision"), which NHTSA is investigating for visibility failures.
CBI
Confidential Business Information. Data withheld from public disclosure in NHTSA filings because manufacturers claim it contains trade secrets or proprietary details.
Co-Pilot360
Ford's umbrella brand for its suite of ADAS features including lane-keeping, adaptive cruise control, and BlueCruise hands-free driving on select models.

D

DDT
Dynamic Driving Task. The real-time operational and tactical functions required to operate a vehicle in on-road traffic, including steering, braking, accelerating, and monitoring the driving environment.
Disengagement
An event where an autonomous driving system deactivates and transfers control to a human driver, either automatically (system-initiated) or manually (driver-initiated). California requires AV companies to report disengagement data annually.
DMS
Driver Monitoring System. A camera-based system that tracks the driver's eye gaze, head position, and attention level to ensure they remain engaged while using ADAS features. GM's Super Cruise and Ford's BlueCruise use infrared DMS; Tesla's implementation has been criticized as less rigorous.

E

Edge case
An unusual or extreme driving scenario that an autonomous system may not handle well — such as unusual road markings, construction zones, emergency vehicles, or unexpected obstacles. Edge cases are a primary challenge in AV safety.
EyeSight
Subaru's stereo-camera-based ADAS system providing pre-collision braking, adaptive cruise control, and lane-keeping assist. One of the longest-running production ADAS systems, introduced in 2008.

F

FMCSA
Federal Motor Carrier Safety Administration. The U.S. agency responsible for regulating commercial motor vehicles (trucks and buses), including autonomous commercial vehicles.
FMVSS
Federal Motor Vehicle Safety Standards. The set of U.S. federal regulations prescribing minimum safety performance requirements for motor vehicles. AV developers sometimes seek exemptions from FMVSS for vehicles without steering wheels or pedals.
FSD
Full Self-Driving. Tesla's branded advanced driver assistance feature. Despite the name, it is classified as Level 2 ADAS and requires constant driver supervision. NHTSA is investigating 3.2 million FSD-equipped vehicles.

G

Geofencing
The practice of restricting an autonomous vehicle's operation to a specific geographic area using GPS boundaries. Waymo, for example, operates within geofenced zones in San Francisco, Phoenix, and Los Angeles.

H

HD Map
High-Definition Map. A centimeter-accurate 3D map of road geometry, lane markings, traffic signs, and infrastructure used by some AV systems for precise localization. Waymo and GM's Super Cruise rely on HD maps; Tesla does not use them, arguing camera-based perception is sufficient.

I

IIHS
Insurance Institute for Highway Safety. A nonprofit organization funded by auto insurers that conducts vehicle crash testing and rates ADAS features. Their safeguard ratings evaluate partial automation systems.
ISO 26262
An international standard for functional safety of electrical and electronic systems in production automobiles, including autonomous driving systems. It defines Automotive Safety Integrity Levels (ASIL A-D) based on severity, exposure, and controllability of potential hazards.

L

Lidar
Light Detection and Ranging. A remote sensing technology that uses laser pulses to create precise 3D maps of surroundings. Used by Waymo, Zoox, Cruise, and most AV companies except Tesla. Provides centimeter-level accuracy in all lighting conditions.

M

Minimal Risk Condition
A stable, stopped condition to which an ADS automatically transitions when it can no longer perform the driving task safely — such as pulling to the road shoulder and stopping. Required behavior for Level 3+ systems.
MRC
Minimal Risk Condition. The fallback safe state an ADS must achieve when it can no longer operate safely — typically pulling to the shoulder and stopping. Required behavior for Level 3+ systems. Failure to achieve MRC can result in crashes, as seen in some Cruise incidents.

N

NCAP
New Car Assessment Program. Government-run vehicle safety rating programs (e.g., NHTSA's 5-Star Safety Ratings, Euro NCAP) that increasingly evaluate ADAS and AV features.
NHTSA
National Highway Traffic Safety Administration. The U.S. federal agency responsible for motor vehicle safety, including autonomous vehicle oversight, the Standing General Order crash reporting program, and defect investigations.

O

ODD
Operational Design Domain. The specific conditions under which an ADS is designed to function, including geographic boundaries, road types, speed ranges, weather, and time of day. A system operating outside its ODD may fail.
ODI
Office of Defects Investigation. The division within NHTSA that investigates potential safety defects in motor vehicles and equipment, including autonomous driving systems. Responsible for the Tesla FSD probe (EA26-001).
OTA
Over-the-Air update. Software updates delivered wirelessly to vehicles. Tesla pioneered automotive OTA updates and has used them to implement NHTSA-mandated recalls affecting millions of vehicles without physical dealer visits.

P

Phantom braking
When a vehicle's automated system perceives a non-existent obstacle and initiates sudden, unexpected braking. The most common Tesla Autopilot complaint, worsening significantly after Tesla removed radar sensors in 2021.
ProPILOT
Nissan's branded ADAS system offering adaptive cruise control and lane-centering on highways. ProPILOT 2.0 adds hands-free single-lane driving on compatible roads in select markets.

R

Radar
Radio Detection and Ranging. A sensor technology using radio waves to detect objects, their distance, and speed. Most automakers use radar for adaptive cruise control and collision avoidance. Tesla controversially removed radar from most vehicles in 2021–2022.
Remote operator
A human who monitors and can intervene in an autonomous vehicle's operation from a remote location. Some AV companies use remote operators as a safety layer, providing guidance when the vehicle encounters situations it cannot resolve.
Robotaxi
A fully autonomous vehicle operating as a ride-hailing or taxi service without a human driver. Waymo and (formerly) Cruise operate commercial robotaxi services in select U.S. cities. Robotaxis are classified as ADS (Level 4) and must report all crashes to NHTSA regardless of severity.

S

SAE Level 0
No Driving Automation. The human driver performs all driving tasks. The vehicle may have warning systems (e.g., blind-spot alerts) but no sustained vehicle control.
SAE Level 1
Driver Assistance. The system can assist with either steering OR acceleration/braking, but not both simultaneously. Examples: basic adaptive cruise control, lane-keeping assist.
SAE Level 2
Partial Driving Automation. The system can control both steering and acceleration/braking simultaneously, but the human driver must monitor at all times and be ready to intervene. Examples: Tesla Autopilot, GM Super Cruise, Ford BlueCruise.
SAE Level 3
Conditional Driving Automation. The system performs the entire driving task within its ODD. The human must be ready to take over when requested, but need not continuously monitor. Example: Mercedes-Benz DRIVE PILOT (approved in select U.S. states).
SAE Level 4
High Driving Automation. The system performs the entire driving task within its ODD without any human intervention required. If it cannot continue, it achieves a Minimal Risk Condition on its own. Examples: Waymo, Zoox robotaxis.
SAE Level 5
Full Driving Automation. The system can perform the entire driving task under all conditions that a human driver could manage. No geographic or environmental restrictions. No production vehicle has achieved Level 5.
Safety driver
A trained human operator who sits in an autonomous vehicle during testing or early deployment, ready to take over if the system fails. Required in most U.S. states for AV testing on public roads.
Sensor fusion
The process of combining data from multiple sensor types (cameras, lidar, radar, ultrasonic) to create a more complete and reliable understanding of the vehicle's environment. Used by most AV companies except Tesla.
SGO
Standing General Order. NHTSA's mandatory crash reporting requirement (SGO 2021-01) for vehicles equipped with ADS or Level 2 ADAS. Fatal/serious crashes must be reported within 1 day; others within 10 days. The foundation of AutoPilotWatch's database.
Super Cruise
GM's hands-free Level 2 ADAS system for divided highways. Uses lidar-mapped roads, GPS, cameras, and a driver attention system. Available on select Cadillac, Chevrolet, and GMC models. Rated highly by Consumer Reports.
SOTIF
Safety of the Intended Functionality (ISO 21448). A safety standard addressing risks from the intended behavior of autonomous systems, such as misclassification of objects or inappropriate responses to edge cases — as opposed to hardware/software malfunctions covered by ISO 26262.

T

Teleoperations
The remote monitoring and control of autonomous vehicles by human operators via wireless communication. Used as a fallback when AV systems encounter edge cases. Companies like Waymo and Zoox employ teleoperators.
TSB
Technical Service Bulletin. Manufacturer-issued instructions to dealers for fixing known vehicle issues that don't rise to the level of a formal recall. TSBs related to ADAS/ADS can indicate emerging safety patterns.

U

Ultrasonic
Short-range sensors using sound waves to detect nearby objects, commonly used for parking assist and low-speed collision avoidance. Tesla controversially removed ultrasonic sensors from its vehicles in 2022, relying solely on cameras for close-range detection.

V

V2X
Vehicle-to-Everything communication. Wireless technology enabling vehicles to communicate with other vehicles (V2V), infrastructure (V2I), pedestrians (V2P), and networks (V2N). Expected to enhance AV safety but not yet widely deployed.
VIN
Vehicle Identification Number. A unique 17-character code assigned to every motor vehicle for identification. Used to look up recalls, investigations, and reported incidents for specific vehicles.
VMT
Vehicle Miles Traveled. A measure of total miles driven, commonly used to normalize crash rates for fair comparison between companies with different fleet sizes.

W

Waypoint
A specific geographic coordinate that an autonomous vehicle's route planner uses to define its intended path. ADS vehicles navigate between waypoints using a combination of HD maps, real-time perception, and path planning algorithms.

How to Use This Glossary

This glossary covers the key terms, acronyms, and technologies used in autonomous vehicle safety reporting and regulation. Each term is linked with a unique anchor so you can reference specific definitions from other pages or share them directly.

For journalists: Use these definitions to ensure accurate reporting on AV safety. The distinction between ADS and ADAS, for example, is critical for understanding incident data and manufacturer comparisons.

For consumers: If you own a vehicle with driver-assist features, understanding terms like phantom braking, OTA updates, and disengagement will help you interpret safety information and make informed decisions.

For researchers:We've included regulatory terms (SGO, ODI, FMVSS) alongside technical terms (lidar, sensor fusion) to provide a complete reference for AV safety analysis.

Related Resources

❓

FAQ

📋

Methodology

ℹī¸

About

đŸ“Ĩ

Downloads

Missing a term?

If there's a term you'd like us to add, let us know.