As parts of Cambridge, Somerville, Charlestown, and Everett grow rapidly (“Seeing green around Orange Line,’’ Page A1, Aug. 6), it will be important for this growth to be transit-oriented so that the trips it creates do not exacerbate congestion. The amount of growth projected by the Metropolitan Area Planning Council within this Lower Mystic area could create more than 500,000 new daily auto trips by 2040, or double the traffic that currently travels through the area on Interstate 93.

My agency is working with these municipalities and state officials to identify ways to increase public transit use and decrease auto trips generated by the new development. A critical strategy that local and state regulators need to emphasize in the permitting of these sites is to limit the amount of free parking. Our research shows that in transit-rich areas, limiting parking and pricing what is built at market rates are two of the most effective methods of encouraging transit ridership.

These sites are all a short walk to the Orange Line and are served by numerous MBTA bus routes, which also deserve better service if we want to make a dent in auto dependence along this corridor. While the level and quality of transit service needs to increase, fewer trips will be on the MBTA regardless if all these new commercial and residential buildings include excessive parking.

Eric Bourassa

Director of transportation

Metropolitan Area Planning Council

Boston