Guardrails on the nation's highways are supposed to protect us. Too often, though, they have inflicted harm. Patrick G. Lee investigated how a Texas company altered its taxpayer-funded guardrail system under the government's nose, to potentially deadly effect. Months before other media, Lee exposed the potential hazard posed by Trinity Industries Inc.'s ET-Plus end terminal, a 175-pound piece of steel mounted at the ends of a guardrail. Intended to absorb the force of a crash, some of them lock up, piercing cars and their occupants. Lee recounted one would-be whistleblower's cross-country quest, starting in late 2011, to learn why these systems were spearing cars. The discovery: Trinity had modified the ET-Plus more than a half-decade earlier without telling regulators. The newer version, modified to cut manufacturing costs, was malfunctioning, several plaintiffs alleged.