Be careful what you ask for. In Portland a 20 bike pile-up in a 'cattle-shute' type of bike lane wouldn't be out of the realm of possibility. And even if you didn't go down in the first wave of casualties you would still have to hump your 50lb. fully decked commuter rig over 18" of concrete and back. What is wrong with people? How many miles of barrier is reasonable? What cost for 1,000... 2,000... 6,000... miles of barrier? Automobile drivers would insist that cyclists pay for it themselves. How many committed road cyclists are there and would they suddenly vanish off the radar when called on to step up and pay their apportionment. Be careful what y'all's wish for.