Carlos Solis was driving a familiar route, the few miles from his home to his brother’s apartment outside Houston, on a Sunday in January last year. His cousin sat beside him, and a dog was in the back seat. Just as they turned into the complex, their car, a 2002 Honda Accord, was hit. It was a low-speed collision with modest damage. Both front air bags deployed. Solis’s cousin got out of the car uninjured. The dog was fine, too. But Solis didn’t move. He’d been hurt, though at first it wasn’t obvious how. His cousin called Solis’s brother, Scott, who ran to the car. Scott tried to stanch the flow of blood from a deep wound in Solis’s neck; so did the paramedics.