California must be on the yellow brick road, while other parts of the country are rust red uninfluenced by research and still tripping people and bicycles.
Several years ago when they implemented truncated domes and tactile warning devices, my new clinic was delayed from opening for three months because the ADA had not yet established the criteria for the bumps, but yet they were mandated for opening the building. We invested in concrete ones, concrete bumps painted red and finally red rubber inserts before being approved emphasizing my point about regulation.
For example in Philly alone, the cost of installing the now-mandated ramps at each of the city's 22,000 intersections will be $858 million, according to Streets Department Deputy Commissioner David Perri, consuming 65% of the cities paving budget.