On Tuesday, the Ford Motor Company became the latest car maker committed to putting a fully autonomous car into production in the next five years. "The world is changing, and it's changing very quickly," Ford CEO Mark Fields said. The company intends to build a high-volume car capable of SAE's level 4 autonomy, but the target customer is not regular consumers—it's ride-sharing services. "Starting in 2021, if you want to get around the city without the hassle of driving or parking, Ford's new fully autonomous vehicle will be there for you," Fields said.

The announcement took place in Palo Alto, outside Ford's Silicon Valley Research and Innovation Center. As part of Ford's future plans, that research center will double in size over the next 16 months. Although Fields cited the safety implications of autonomous cars—90 percent of traffic crashes are attributable to human error, after all—he was also enthusiastic about the possibility of making transportation more accessible to the elderly, disabled, and people too young (or too disinterested) to drive themselves.

Ford has designs on being more than an automaker, too; the company's Smart Mobility pilot programs have been showing the way here. "We know there's no such thing as a one-size-fits-all transportation solution," Fields said, adding that ride-sharing would make more efficient use of vehicles, with less time wasted for people and less pollution.

To make that 2021 deadline, Ford is investing in lidar sensor-maker Velodyne and 3D mapping company Civil Maps. Additionally, it has acquired the machine vision company SAIPS and has entered into a licensing agreement with a second, Nirenberg Neuroscience.

Skipping straight to level 4

Ford's CTO Raj Nair took the podium after Fields to lay out the company's strategy for getting to fully autonomous cars in five years. "We're tripling our investment in driver assist technologies like traffic jam assist and remote parking in the next three years. But where we see the greatest opportunity is where we're able to remove the driver from the responsibility of driving altogether—SAE levels four and five," Nair said. That will involve Ford tripling the size of its autonomous research fleet by the end of this year and then tripling it again in 2017.

And forget about more incremental steps in driver assist technologies. "Today we're looking at this differently," Nair said. "We have to take a completely different path." That means no level 3 autonomous Ford. Nair said that Ford's researchers still haven't found a satisfactory solution to the problem of returning control to a human driver in a safe manner (a level 4 car by contrast has no steering wheel and requires no human control beyond inputting the destination).

Expect level 4 cars to take quite a while longer to reach private hands. "The economics simply don't make sense," Nair said. But the cost of operating a taxi or shuttle bus without having to pay a driver to operate it makes a more compelling case. Indeed, Uber is hard at work in Pittsburgh testing a self-driving car of its own for just that reason.