Self-driving cars are all over the news but not all self-driving technologies are as self-driving as others. Tom Merritt explains the differences between level 1 through 5.
Not all self-driving technologies are as self-driving as others. The Society of Automotive Engineers (SAE) and the US National Highway Traffic Safety Administration (US NHTSA) have both issued guidelines for what the various level of autonomy mean in cars.
Level 0 means humans do everything in both systems. Here are the 5 other levels of autonomous driving. To keep things clear we'll give you the SAE levels and then explain where the US NHTSA fits in.
For the SAE this means Parking assistance, lane keeping and systems where the driver has to be ready to take control at a moment's notice. The US NHTSA calls that Level 2. The NHTSA's level one is individual systems like automatic braking.
For the SAE this is the car driving most of the time with the driver intervening for events or unexpected objects. The system deactivates as soon as the driver takes over.
Both the SAE and NHTSA say at level 3 the driver can cede all safety-critical functions to the car under certain conditions. The SAE defines level 3 as operating in known limited environments like freeways. Otherwise the driver has to pay attention.
The SAE calls level 4 the one where the car can do the driving in all but a few environments like severe weather. That's covered in level 3 by the NHTSA.
No human driver is required. The car doesn't even need steering wheels or brake pedals, as the machine does all the driving. The NHTSA calls this level 4.
Now when somebody says autonomous car you can ask what level. And then whether they mean SAE or NHTSA. But hey, you'll at least get a little clarity.
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