Ah, I missed that. However that doesn't mean increasing the speed limit would be bad. Instead of speeding tickets they could focus on aggressive drivers constantly changing lanes and other more serious maneuvers that could cause more danger.
There are hundreds of studies on increasing the speed limit. Most say increasing the limit causes increased fatalities, others say the effect is negligible. Most of these studies focus on highway speeds, though.
But lowering street level speed limits has a dramatic effect on fatalities. Sweden reduced their street speed limits to 15-20mph and strictly enforced them.[1] This dropped their fatality rate to essentially zero. It didn't reduce accidents significantly, but reduced their severity massively.