Which technology do self-driving cars use to detect the presence of other cars?

• A. Radar detection
• B. Infrared imaging only
• C. Magnetic field sensing only
• D. Ultrasound without any other sensors

Answer: (A)

Sensing other vehicles in self-driving cars relies on radar because it uses radio waves to detect objects at distance and measure their speed. Radar can provide range and velocity information even in rain, fog, or darkness, which is crucial for safe following distances and braking decisions. Infrared imaging alone isn’t reliable for identifying other cars since it mainly detects heat and doesn’t consistently give accurate distance or object recognition in all conditions. Magnetic field sensing isn’t a standard, dependable way to detect moving vehicles, and ultrasound, while great for close-range sensing like parking, has a very short range and can’t effectively detect distant cars at highway speeds. In real systems, radar is often used alongside cameras and lidar to create a robust understanding of nearby traffic, but radar remains the most appropriate single technology for detecting the presence and speed of other cars.