CARS are set to change more in the next couple of decades than in the 130 years since Karl Benz fitted a small four-stroke engine to a large tricycle. Cars, once largely mechanical devices controlled by humans, are increasingly employing complex technology that is taking over many of the functions performed by the driver. The end point of these developments is routinely referred to as self-driving or autonomous cars. The two terms are used interchangeably (even by this newspaper). But carmakers, including the bosses of Volvo and Renault Nissan, are keen to draw a distinction between the two, and with good reasons of self-interest. Autonomous cars will look like the vehicles we drive today, according to carmakers, with forward facing seats and a steering wheel. These cars will take over from the driver under certain circumstances. Some elements of autonomy are already available. Self-parking, adaptive cruise control—which adjusts speed to keep a safe distance from cars ahead—and automated braking are available on quite modest machines. In the near future autonomous vehicles might take over driving completely in heavy traffic or on motorways.

Self-driving cars are a stage further on. The steering wheel will disappear completely and the vehicle will do all the driving using the same system of sensors, radar and GPS mapping that autonomous vehicles employ. While some personal cars will remain, a fleet of shared vehicles will likely fill the streets of towns and cities. Call up a car with a mobile device, key in the destination and the vehicle will do all the work.

Carmakers are in favour of autonomous cars. Autonomy still implies personal ownership but with a raft of extra features that they can charge for. Self-driving vehicles, on the other hand, change the landscape of personal transportation dramatically. Barclays, a bank, reckons that if the cost can be brought down and the legal and regulatory issues overcome, vehicle sales will fall by 40% as “robotaxis” and other shared vehicles replace personal car ownership. Mass market carmakers will face a hugely diminished market and premium brands’ cachet may not have much sway for self-driving or shared vehicles. Unfortunately for carmakers, autonomous vehicles are the technological forerunners of self-driving cars that may bring about their doom.

Dig deeper:

Carmakers will beat tech firms at building the cars of the future (February 2015)

How do self-driving cars work? (April 2013)