Two key architects of change at NYC DOT are moving on after seven years with the agency. DOT Traffic and Planning Commissioner Bruce Schaller departed at the end of May, and DOT Policy Director Jon Orcutt announced on Twitter yesterday that he will be leaving next week.

Orcutt and Schaller were two of former DOT chief Janette Sadik-Khan‘s major hires after she took over as transportation commissioner in 2007. They each played leading roles implementing reforms that prioritized safety, efficiency, and public life on New York City streets, and both leave tremendous legacies.

Orcutt came to DOT from a career in advocacy, starting with Transportation Alternatives in its formative late 1980s period and moving on to the Tri-State Transportation Campaign, where he was a founding staffer and later executive director. He led the development of DOT’s first strategic plan in 2008, which set the stage for many reforms that followed, and in the early days of the de Blasio administration he was the lead on the Vision Zero Action Plan.

Inside the agency he was known for pressing for bold changes. He had a hand in too many projects to count, but spearheading the development and launch of bike-share tops the list. Count the implementation of the Brooklyn Waterfront Greenway, the city’s new pedestrian wayfinding program, and the introduction of protected bike lane designs among his other major contributions.

Schaller had stints in public service before joining DOT, but in the years leading up to his time at the agency, he was best known for a series of reports from his consulting firm, examining everything from regional driving patterns to the travel habits of neighborhood shoppers. At DOT, his data-driven brand of communications helped the agency tell the world about its work in new and rigorous ways. The reports produced by DOT clearly conveyed the safety improvements, economic impacts, and other benefits attributable to the agency’s street overhauls.

The launch of Select Bus Service and the PARK Smart meter pricing program were signature Schaller initiatives. He helped deploy new public engagement methods that went beyond the simplistic “yes” or “no” format of a community board meeting, like the workshops about neighborhood parking policy DOT held in 2007 and 2008. Behind the scenes, he brought agency staff working on sustainable transportation initiatives and traffic operations under one roof, allowing for tighter integration of transit, walking, and biking improvements into more DOT projects.

Along with Andy Wiley-Schwartz, who led the DOT plaza program and left the agency at the end of January, Orcutt and Schaller comprised what Streetsblog called the “DOT Dream Team” — new managers brought on by Sadik-Khan to help realize the PlaNYC goals related to streets and transportation. By all accounts they are parting amicably after making significant contributions to the de Blasio administration’s Vision Zero initiative.

Nevertheless, this is a pivotal moment for the agency and commissioner Polly Trottenberg.

DOT has a deep roster of talent that has grown along with the agency’s reputation for implementing innovative, effective street redesigns. Orcutt and Schaller didn’t get stuff done by themselves. The agency has the capacity to keep up the pace of change, despite the loss of key leaders, and the de Blasio administration’s transportation policy goals don’t lack for ambition. But Trottenberg has yet to face a hard political test at DOT — the agency’s response when the going gets tough may determine whether its best people stay on.