Of the futuristic technology we see in movies and television, few have the appeal — and the sense of being tantalizingly close — as self-driving or autonomous vehicles. Today, we have cars and trucks with some autonomous or driver-assist features, but they aren’t quite the promise of the driverless cars we see in science fiction. The conversations about this mostly revolve around passenger cars navigating in cities, which still depend on a person who can take the wheel in case the computers crash and the technology fails. But perhaps we are a bit closer to that futuristic scenario when it comes to self-driving semitrucks. Marketplace’s Kimberly Adams speaks with Christopher Mims, a tech reporter at The Wall Street Journal. He recently wrote about the specialized technology behind autonomous big rigs.