Crunican's tenure also saw an unprecedented spike in BART ridership -- the number of weekday passengers grew by more than 30 percent between fiscal 2009-10 and fiscal 2015-16.
The dramatic increase in patronage was followed by equally dramatic overcrowding, occasional major service disruptions because of failing equipment, and a rising tide of customer complaints about everything from station and train cleanliness to fare evasion to crime on the system. The agency's most recent rider survey, released in January, showed overall customer satisfaction at an all-time low.
Crunican's reign also coincided with a series of high-profile crimes that stoked widespread media attention and complaints that BART doesn't do enough to keep its riders safe.
In one episode, in January 2016, a passenger aboard a San Francisco-bound train at the West Oakland Station was shot and killed by another rider. Following reports in the San Francisco Chronicle that most of what appeared to be security cameras aboard trains were actually non-operational decoys, BART was forced to admit it had no video from the car where the crime occurred. The agency subsequently installed cameras aboard all its trains.
The outcry about crime on BART reached its peak last July when three homicides occurred on the system.
Nia Wilson, 18, of Oakland, died in a stabbing July 22 at Oakland's MacArthur Station. The suspect, John Lee Cowell, 27, was arrested the next day after being spotted aboard a BART train. A judge is currently weighing psychiatric evidence about Cowell's competence to stand trial.
Wilson's death occurred just days after two other homicides linked to the system -- one at Bay Fair Station, the other at Pleasant Hill.
Crunican responded with what she called "a comprehensive security and action plan" to improve safety throughout the 47-station, 120-mile system.
The 12-point program included proposals for training agency workers to fill temporary station security roles, an anti-panhandling ordinance, new emergency call boxes for station platforms and enhanced customer education. It also proposed beefing up the district's surveillance capabilities by expanding the number of cameras on BART property and employing a new centralized system to help monitor them -- measures that were deferred after privacy advocates raised concerns.
Perhaps the most difficult and controversial chapter in Crunican's career at BART occurred in 2013 when the agency endured two strikes.
Crunican and the board hired a hardline negotiator, Thomas Hock, to confront union representatives determined to win significant raises after granting concessions during the economic downturn and an agency budget crisis four years earlier. The two sides came to an impasse not once but twice, with workers walking out in a pair of four-day actions in July and October 2013.
Beyond the impact to the commuting public, the second walkout, and BART's decision to prepare to use nonstriking replacement train operators, led directly to a tragedy.
Two men working alongside tracks between Pleasant Hill and Concord -- Christopher Sheppard, a BART employee, and contractor Laurence Daniels -- were killed when a four-car train with a trainee at the controls hit them while traveling 60 to 70 mph.
The National Transportation Safety Board ruled that BART's lax safety practices were the probable cause for the deaths. The California Public Utilities Commission last year fined BART $1.3 million in connection with the incident and put the agency on three years' probation.
A consultant's analysis of the labor conflict detailed the rampant mistrust between workers and management and the traumatic aftermath of the strikes, and made dozens of recommendations for how to avoid a repeat -- including an early start to the next round of negotiations.
BART and its unions reached an agreement on their 2017 contract nearly a year early. The current contracts expire in 2021.
In her retirement announcement to the board, Crunican expressed both pride in BART's current direction and confidence that the agency will thrive in coming years. She pointed to Measure RR, the $3.5 billion infrastructure investment bond, and a range of other initiatives, including adopting a districtwide transit-oriented housing development program and embracing LGBTQ firms as part of BART's small-business contracting program.
"A capable, diverse and energetic team of new leaders is in place to take BART into the next decade," she said. "This team is joyful and bold and hardworking. They are customer-focused and have made operational changes that have translated into cleaner stations, almost universal Clipper Card usage, good relations with labor unions for several years and communication systems that stay ahead of our mobile customers, just to name a few."
She added: "Despite the challenges, and we all know that some days have been better than others, I am fortunate to have had this opportunity to serve you and the customers who rely on BART."
