Originally Posted by FBinNY

Assuming it works it's a great concept. Rather than through enforcement it addresses the speeding straight on by eliminating the reason to do so.

NYC has controlled speeds on the one-way avenues for decades through timed lights, and that's worked well. Speed and separation on our subways have also been managed through a signal system that allows closing the gap to a switch or train ahead only at low speeds, while allowing greater speeds when the way is clear.

I hope this works in Phila, and that other areas take note.