Long before an Arizona woman stepped off a curb and into transportation history under cover of darkness Sunday night, some circumstances surrounding her death in a collision with an Uber self-driving test vehicle had already been determined. 
As in so many other places in the Sun Belt, traffic engineers had built this road in Tempe with cars foremost in mind. Mill Avenue stretches five full lanes across at the point where she attempted to cross: two for vehicles turning left at the upcoming intersection with Curry Road, two for vehicles traveling straight, and a right-turn lane at the far side. Wide roadways like this are common sights in Arizona, a state with the fourth-highest rate of pedestrian fatalities in the country.
Paths crisscross a shrub-covered island that separates the northbound lanes of Mill Avenue from the southbound ones. A sign deters pedestrians from crossing there, instead instructing them to use the crosswalk at the intersection ahead. But depending on exactly where Elaine Herzberg attempted to cross?and police haven?t released precise information on the point of impact yet?that crosswalk was at least several dozen feet away, and perhaps several hundred. When she stepped off the curb, pushing her bicycle, she entered a road environment where the state?s governor had eagerly welcomed self-driving vehicles and the companies testing this fledgling technology. In December 2016, when Uber ran afoul of California regulations that mandated the company hold...