New Parking Ratios & TDM Point System Tool: Aligning Transportation Development Review Process with Citywide Goals

Written by Marissa Rivera, TMA Operations Manager

On October 12, 2021, Major Kim Janey announced the launch of updated review guidelines for new developments over 50,000 square feet. Created by the Boston Transportation Department (BTD) in partnership with the Boston Planning & Development Agency (BPDA) and the Environment Department, updated maximum parking ratios and a new TDM Point System bring a consistent and transparent approach to implementing effective Transportation Demand Management (TDM) strategies at new large developments. The TDM Point System was developed in collaboration with Stantec and Allison Simmons, TDM-CP.

Prior to the release of this new system, TDM measures for large new developments were typically negotiated with the City of Boston on a case-by-case basis. As a result, TDM approaches and outcomes among previously approved developments tend to vary widely. In standardizing the transportation review process, Boston intends to provide increased consistency, certainty, and transparency for both developers and the public. By taking a cohesive approach to disincentivizing single occupancy vehicle (SOV) usage at large new developments, standardization of the process also supports progress toward Go Boston 2030 mode shift goals and the related Carbon Free Boston goal of net neutrality by 2050.


The updated transportation development review guidelines contain two key and mutually supportive initiatives. First, new maximum parking ratios reflect the belief that new developments should align their planned parking to complement rather than counteract the amount of access to transit, walking, and micromobility surrounding the site. Working with members of the BPDA and Environment Department, BTD assigned a mobility score to each parcel in the city using criteria including the number of jobs accessible by transit in 30 minutes, walkscore, restricted parking zones, and proximity to grocery stores, rapid transit, and multimodal transportation. The higher the resulting mobility score is for a given parcel, the lower its maximum parking ratio will be for a new development. Parking maximums are further adjusted to consider the varying transportation needs of residential, hotel, retail, office/lab, institutional, and industrial developments. It is important to note that, counter to past practice, no parking minimums exist.

The second key initiative within the development review guidelines is a new TDM Point System, which BTD released simultaneously to facilitate utilization of the mobility options shaping these parking ratios. This online tool provides a framework to determine the ideal impact of TDM measures at a proposed site and to present an appropriate set of corresponding strategies for the developer to employ. Using the same mobility scores underlying the maximum parking ratios, the tool assigns a TDM point target for a proposed development, with higher mobility scores corresponding to higher TDM point targets. Taken together, the maximum parking ratio system and TDM point tool mean that new developments proposed for walkable and transit-rich areas will be required to have relatively fewer parking spaces and more incentivization of non-SOV transportation modes than new developments in areas with lower mobility scores.


In shaping these new systems the BTD engaged with multiple members of the A Better City (ABC) community. After vetting its proposed parking ratios with several ABC member developers and institutions in January 2020, BTD engaged ABC under the American Cities Climate Challenge (ACCC) in spring 2020 to survey business community members and better understand their attitudes towards potential TDM measures. The resulting data, published over three reports, reinforce the importance of systemically shaping transportation demand in order to avoid increased congestion and greenhouse gas emissions as metro-Boston recovers from the pandemic.

Over several weeks in February 2021, ABC staff additionally participated in a series of workshops hosted by the Urban Land Institute (ULI) convening developers and the architects of the new system; feedback provided through these workshops helped to fine-tune the mobility score system and calibrate land use adjustments. In April 2021, ABC hosted the team leading this initiative for a presentation and conversation with members. ABC has suggested that the point system would benefit from the addition of increased measures related to electric vehicle and bike charging and will continue to advocate for the inclusion of these measures as the tool is updated to reflect leading TDM best practices as they evolve.

Going forward, many of the large developer and institutional members of A Better City will engage with the new maximum parking ratios and TDM Point System as they move through the development review process for proposed projects over 50,000 square feet. Specifically, those planning to file an Article 80 Project will need to engage with the TDM Point System Tool to create the TDM plan required as an attachment to the Project Notification Form. Through A Better City’s Transportation Management Associations (TMAs), we stand ready to support navigation of these measures and compliance with their requirements.

To meet the number of TDM points assigned to a given parcel under this system, developers will choose from a set of baseline, impact, and elective strategies. For each strategy contained within the tool, BTD has provided a fact sheet including a strategy definition, land use applicability, upfront and ongoing costs, difficulty in implementation, submission and monitoring requirements, and anticipated vehicle miles traveled (VMT) reduction impact. A Better City’s TMAs can administer in-house programs designed to fulfill many of these strategies and provide expertise to support members in creating customized plans to meet others.

For questions or comments on the new parking ratios and TDM Point System Tool, please reach out to TDM Director Scott Mullen at For TMA support designing your TDM plan for a new development over 50,000 square feet, please contact TMA Operations Manager Marissa Rivera at



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