Boston has taken some important steps  to improve safety on their streets by implementing vehicle-based safety measures, including side guards, for certain municipal commercial vehicles:

In his letter to Boston City Council, Mayor Walsh stated that the ordinance establishes requirements for protection equipment to be installed on vehicles contracted by the City of Boston, to be constructed and/or equipped as to offer effective protection to unprotected road users against the risk of falling under the sides of the vehicle and being caught under the wheels.

“I am pleased that this life-saving measure, a first in the nation, is moving forward as a result of the Volpe-Boston partnership over the past two years,” said Dr. Epstein. “Side guards, blind spot mirrors, sensors, and other truck technologies are all important means to prevent or mitigate deadly crashes with the pedestrians and bicyclists who must share the road with these massive vehicles. I believe that vehicle-based safety is becoming a key strategy for cities to reach their goals of reducing or eliminating traffic fatalities.” 

http://www.volpe.dot.gov/news/cities-take-steps-increase-bicyclist-and-pedestrian-safety