Most self-driving vehicles, including Google’s various prototypes, are bedazzled with sensors, including cameras, ultrasound, high-accuracy GPS, and expensive laser-ranging instruments known as lidar. These devices help the cars build up a composite picture of the surrounding world in order to drive safely. But some components, such as the lidar, cost tens of thousands of dollars.

In demo that shows how quickly some of the technology is advancing, Magna, a company that supplies components to most large carmakers, showed recently that it can make a car drive itself (on the highway at least) using just a single camera embedded in the windshield. Magna hasn’t said how much the technology would cost carmakers, but vehicle camera systems tend to cost hundreds of dollars rather than thousands. The feat is made possible thanks to rapid progress in the software, which comes from the Israeli company MobileEye, that’s used to interpret a scene.

Nathaniel Johnson, lead control algorithm engineer at Magna, took me for a ride in a Cadillac equipped with the technology. After pulling onto the I-94 just north of Ypsilanti, Michigan, he pressed a button on the steering wheel to activate the system, and then sat back and let the car take over.

“It can drive itself in many situations,” Johnson explained, as the car followed the curve of the road. “It uses various image-processing techniques.”

The entertainment display on the car’s dashboard showed the video feed being processed by MobileEye’s software. Lane markings were highlighted in green, and green boxes were drawn around each vehicle ahead, with numbers showing their distance in feet. The software also instantly recognized traffic signs, and Johnson explained that the automated driving system could be configured to stick to whatever speed the signs showed. It was possible for him to take the wheel for a few seconds, then relinquish it, and have the self-driving system retake control.

Magna has been testing the technology for the past year in trials in the U.S., Germany, the U.K., and most recently China.

The technology wouldn’t be used this way by a carmaker, but would likely be combined with other sensor systems. Even so, it shows that automated driving capabilities could be added to vehicles relatively cheaply. “For higher levels of autonomy, we will require more sensors,” Johnson said. “But this is a nice introductory level of autonomy. It’s something people can afford, and get into their cars.”

Today, automated driving features such as adaptive cruise control and hands-free parallel parking are only offered on high-end vehicles. The Mercedes S-Class sedan, which can automatically follow the car ahead in stop-and-go traffic and will take the wheel to help swerve around obstacles, starts at $94,400 in the U.S. and can cost as much as $222,000.

The price of sensors and related systems will need to come down significantly if the technology is to have as big an impact as many people hope it will.