From the article:
Safety advocates point to other factors that could be at play, including heavier and more powerful new vehicles, street designs that prioritize motorist speed over pedestrian protection, and the increased prevalence of tech tools integrated into vehicle dashboards that could distract motorists.
If you make streets (not roads) complex enough to make bike riders and pedestrians comfortable, they will be complex enough that drivers will drive slower and pay more attention. The hard part will be to rein in the vehicular arms race, as auto manufacturers are raking in the money on the gigantic single-occupancy vehicles.