(Originally published on LinkedIn in June 2024)
“Autonomous”, “automated”, “driverless” and “self-driving” all mean the same thing as far as general public or popular media is concerned – cars that drive on their own without a human driver. For engineers (like me), though, the terminology is a little more nuanced.
Firstly, engineers like to use the word “vehicle” instead of “car” so that vehicles other than personal cars are not left out – trucks, buses, taxis, package delivery vehicles etc. Secondly, for engineers, the word “automated” or “autonomous” doesn’t mean that the vehicle can drive on its own everywhere and all the time. Different levels of automation are defined – 0 to 5.
Level 0 is just there to complete the picture. It means “no automation”, just some warning or assisting features that help a human driver (the driving is done entirely by the human driver). Some examples – blind spot warning or that beeping that keeps you from getting too close to the wall while parking.
Level 1 means “driver assistance” and includes very limited automation, either in longitudinal direction (braking or accelerating) or latitudinal direction (steering). Cruise control at a fixed speed is a good example.
Level 2 means “partial automation” and can include automation in both longitudinal and lateral directions. For example – lane keep assist (automatic steering) and cruise control at the same time.
Level 3 is “conditional automation” and is, believe or not, the most complicated of all for engineers to design. A level 3 automated vehicle can operate fully automated in very specific scenarios such as traffic jams but the human driver has to be present and ready to take control at any time lest the vehicle isn’t able to continue in automated mode. It’s because of this transfer of control between human driver and the vehicle that makes level 3 the biggest engineering challenge.
Level 4 is called “high automation” and means that a vehicle can drive autonomously, without any need for human supervision or control, in most situations, such as highway driving including the slightly complex maneuvers of entering and exiting the highway or changing lanes.
Level 5 – “full automation” is the theoretical case (so far) where the vehicle can drive completely autonomously anywhere anytime. So far, all the vehicles, both commercially available or prototypes, are NOT level 5. Why? Because it’s just not possible to expose vehicle’s sensors and automation algorithms to and test them for all possible road-traffic scenarios.