If motor vehicles are to be truly autonomous and able to operate responsibly on our roads, they will need to replicate—or do better than—the human decision-making process. But some decisions are more than just a mechanical application of traffic laws and plotting a safe path. They seem to require a sense of ethics, and this is a notoriously difficult capability to reduce into algorithms for a computer to follow. This article will explain why ethics matters for autonomous road vehicles, looking at the most urgent area of their programming. Nearly all of this work is still in front of the industry, which is to say that I will mainly raise the questions here and