Autonomous vehicles are still in experimental stages, but one big step toward seeing them on the road happened in May 2015, when automotive manufacture Daimler unveiled an autonomous truck, the first approved for U.S. roads.
There’s a range of autonomous vehicles that starts with many features like electronic stability control, already in use in most vehicles on the road. According to the National Highway Traffic Safety Administration, the five levels of vehicle automation include:
No Automation (Level 0). Drivers are the only ones behind the wheel of these vehicles. No operational functions are automated, leaving the operator fully responsible for complete and sole control of brake, steering, throttle, and motive power at all times.
Function-Specific Automation (Level 1). One or more specific control functions, such as stability control or pre-charged brakes (the vehicle automatically assists with braking, allowing drivers to regain control of the vehicle or stop faster than possible by acting alone), are automated.
Combined-Function Automation (Level 2). A vehicle has at least two primary control functions that work together, such as adaptive cruise control in combination with lane centering.
Limited Self-Driving Automation (Level 3). Drivers can elect — but don’t have to — to turn over control of all safety-critical functions under certain traffic or environmental conditions. However, drivers can’t completely check-out; they’re expected to be available for occasional control.
Full Self-Driving Automation (Level 4): These look for navigational input to know where to drive, but after telling the vehicle where to go, drivers aren’t expected to step in and take the reins. These vehicles may be operated unoccupied and are able to perform all safety-critical driving functions and continuously monitor roadway conditions.