If you haven't seen analysis of the deadly Amtrak crash in Philadelphia this week, read this agonizing story from the New York Times. Amtrak was quite close to having a system that could have prevented the disaster, but "the system, which was tantalizingly close to being operational, was delayed by budgetary shortfalls, technical hurdles and bureaucratic rules, officials said Thursday."
Technical hurdles, I think the public can understand. Our engineers haven't solved all the problems yet. But budgetary shortfalls and bureaucracy are intolerable. If an effective transit safety measure is within reach, we need to implement it — not later, but now.