Why are pedestrian deaths increasing in the US?

Here are the data from the European Road Safety Observatory:

In the past decade, Europe and the US have reversed positions in pedestrian death rates. It used to be that the number of pedestrian deaths per million population were higher in Europe, now the US pedestrian death rate per million population is now 75 percent higher than in Europe. The following chart compares the change in pedestrian death rates over the last nine year for which data are available for both Europe and the US.

Source: cityobservatory.org