That means more sensors — and more data. Experimental designs for autonomous cars incorporate as many as 16 video cameras, 12 radar sensors, half a dozen ultrasonic sensors, and four or five lidar sensors. And still more sensors and scanners might be necessary to make self-driving cars impervious to exigencies like blinding blizzards and soaking downpours.

“We have seen an explosion in data bandwidth,” said Lee Bauer, a vice president at Aptiv, a supplier of autonomous and driver-assistance systems. Mr. Bauer cited what has become a mantra among autonomous vehicle engineers: Self-driving cars will generate 4 terabytes of data per hour. That includes live information about road conditions, weather, objects around them, traffic and street signs — all of which has to be shared among components in the car and used to make split-second driving decisions.

Automakers are aware of the coming data tsunami.

“They think we need 300 teraflops of computing power,” said Willard Tu, a senior director at chip supplier Xilinx. A teraflop is a trillion operations per second, which means that every vehicle would be a rolling supercomputer. “So the type of pipe and the diameter of that pipe” that is going to connect all these components, Mr. Tu said, “has to be very flexible.” Estimates for how big that pipe needs to be range from 25 to 40 or more gigabytes per second.

The catch? “No one’s solved the problem of how do I stream all that data to the central processor?” said Mr. Tu.

While engineers and automakers agree that today’s cars need to be completely rewired, the question for many is, with what?

Eliminating the cables entirely by using a short-distance wireless system would be the easiest way to bridge the gap. However, wireless systems are susceptible to radio frequency interference, which could affect reliability and endanger lives. And wireless systems are more vulnerable to security threats, said Mr. Weast of Intel.