In addition to making roads safer, a 25 mph speed limit would save $220 million a year in medical payments and lost work that result from accidents, according to the study.
On the other hand, slower speeds also have their costs. The MAPC study estimated that extra time spent in traffic would cost Massachusetts drivers $127 million a year. Also, all that extra gas burned while people sat in traffic would cost about $21 million.
Slower speeds would make neighborhoods more friendly for pedestrians and bikes and could potentially raise property values in those areas—though the study found there wasn't enough research on that final point to draw a conclusion.
On the other hand, there would be some more air pollution, although it would be negligible: an extra $500 per year, across the state, in air-pollution related health care costs, and no associated deaths.
In a statement about the bill and study, Provost said her proposal would affect "certain urbanized streets," not all local roads in the commonwealth.
Interestingly, the study found that reducing the speed limit to 25 mph would lower real-world speeds by just 1.8 mph—an acknowledgement that people drive faster than the speed limit. If people actually drove 25 mph, it would triple the reduction in crashes and double the savings.
Thoughts? Should Somerville and other communities lower speed limits on local roads to 25 mph?