Biking paths in Boston can be narrow, close to busy roads and devoid of protective barriers. To solve this issue, LivableStreets Alliance is striving to create 200 miles of shared-use “greenway” bike paths in the city by 2030.

Residents in the Greater Boston area may soon have access to a 200-mile path, spanning from the Mystic River north of the city to the Neponset River south of it. LivableStreets Alliance, a nonprofit...