Self-driving cars have been a staple of futuristic science-fiction movies forever, but it appears they are finally coming for real.

Ford has been developing a technology known as Traffic Jam Assist that uses adaptive cruise control and sensors from its active park assist to allow cars to steer the car through traffic, a blog from inventor and technology expert Ray Kurzweil reported. Ford should have the technology on the roads by 2017, Kurzweil’s blog reported.

So how does it work? Extreme Tech breaks it down: the car’s adaptive cruise control keeps pace with the car ahead using radar and a mirror-mounted camera. A separate lane assist keeps the car centered and sonar units monitor traffic on the side and behind the car. The driver is also able to take control at any time.

The cars will do more than just help drivers get to their destination safely, they’ll be good for the environment too. If one in four cars has the Traffic Jam Assist technology or similar self-driving technologies, travel times will be reduced by 37.5 percent and delays reduced by 20 percent, Kurzweil’s blog reported. The more efficient traffic flow comes from the cars’ adaptive cruise control, which is better at pacing traffic than the continual cycle of braking and speeding up.

But it also comes with a catch—the self-driving technology would only work on limited access roads with no bicycles or pedestrians and well-marked lines. It also only works under predictable, low-speed conditions, Extreme Tech reported.

Similar technologies already exist, but so far none have the capacity to actually direct a car toward its destination. Volvo has a city and pedestrian safety feature that stops cars before potential accidents on urban roads, but stopping is about all this can do. Ford also has a park assist technology that helps drivers with the tricky parallel parking, and with the new self-driving cars this feature would extend to perpendicular parking as well.