By Joseph A. Curtatone

(The opinions and views expressed in the commentaries and letters to the Editor of The Somerville Times belong solely to the authors and do not reflect the views or opinions of The Somerville Times, its staff or publishers)

Soon you should see signs popping up around Somerville announcing that the citywide speed limit is 25 mph, unless otherwise posted. We are working to drop the speed limit from 30 to 25 on most roads for one simple reason: Because the data show that slowing down saves lives.

A growing body of research shows that, at the range of speeds people tend to drive in cities (about 20-40mph), for every mile slower you drive, you are less likely to cause severe injury or death should your car strike a pedestrian—or cyclist. For example, the data show that when struck by a vehicle going 40 mph, only one in ten pedestrians survive. Conversely, when struck by a car going just 20 mph, nine out of ten pedestrians survive.

In Somerville, currently more than 16,000 people—including school kids—commute by foot, and 12.5% of our commuters travel by bike. Meanwhile, our annual pedestrian and bike counts show the numbers of walkers and cyclists are increasing each year. So making our streets safer via lower speed limits is not just the right choice here, it’s a life-saving choice.

Slower speeds are safer for drivers as well. Slowing down not only decreases the likelihood of pedestrian fatality if a crash occurs, studies show that slower driving speeds can also lead to fewer crashes overall.

It’s true, not all drivers obey the speed limit. But lowering the speed limit does act as a catalyst for behavior change. In London, which has had numerous lower-speed zones for a couple of decades, an analysis of data found that average speeds dropped by 9 mph when they dropped the speed limit from 30 to 20 mph. Every driver was not necessarily going 20 mph, but on average they were going 9 mph slower than before, and as I noted above, every mile slower makes a difference.

The efforts around increasing safety by lowering speed limits here in Somerville have been going on for quite some time and a few people deserve recognition and thanks. Ward 3 Alderman Bob McWatters, who also serves on the Traffic Commission, proposed lowering the speed limit through a Home Rule Petition, which was approved by the Board of Aldermen and sent to the State legislature.

Before the legislature was able to take action on the Home Rule Petition however, Somerville’s own State Representative Denise Provost successfully added language to the Municipal Modernization Act granting all cities and towns the ability to decrease speed limits to 25 mph in thickly settled areas, and to designate specific safety zones with speed limits of 20 mph.

Thanks to the final passage of Municipal Modernization Act (which goes into effect November 7), we no longer need the Home Rule Petition to lower speed limits, but it was instrumental in helping us to make our case to the state that this is something cities and towns need. And thanks to our Board of Aldermen, we were quickly able to get a 25 mph plan locally approved.

As an additional measure of safety, we intend to make use of the 20 mph provisions in the act as well. Just as we already do in school zones, we’re aiming to establish 20 mph speed limit safety zones in vulnerable, pedestrian-centered areas. These include streets that pass by playgrounds, hospitals, parks, places of worship, and areas frequented by senior citizens (senior housing, assisted living facilities, and community centers that regularly host senior programming).

The data again makes a compelling case for this. AAA data shows that the likelihood of serious injury or death is increased for seniors hit by cars while walking. Researchers have found that London’s 20 mph zones also particularly protect children. A study by the London School of Hygiene and Tropical Medicine showed that over 20 years, the 20 mph zones saw a 50 percent reduction in collisions with children (aged 1-15 years) that caused serious injuries or death—50 percent. We can’t ignore those numbers.

We also shouldn’t delay. We’re aiming to roll out these changes quickly. Just last week the Board of Aldermen voted to accept the state policy allowing the reduction of speed limits throughout the city. The next step is for it to go before the Traffic Commission on October 20. Assuming they pass the proposal, we’ll order new 25 mph signs swiftly, and continue our review for the 20 mph zones.

As the most densely populated city in New England, lowering speed limits is a crucial part of keeping all residents and visitors safe. But it is just that – a part of the bigger solution. We must also continue to invest in infrastructure improvements and a mobility plan that make it easier and safer for residents and visitors to get out and explore all that Somerville has to offer.

So while these changes are being rolled out, it’s important to keep in mind what we can each be doing in the meantime to keep our neighbors and ourselves safe. Obey all traffic laws – that includes pedestrians and bicyclists too. Use crosswalks, be mindful of bike lanes, and slow down in residential neighborhoods because lives depend on it.