Here is a timeline of events in contract negotiations between Amalgamated Transit Union Local 192 and transit agency:
June -- Amalgamated Transit Union Local 192's contract with AC Transit expires.
August -- Union members vote down first tentative agreement.
Oct. 2 -- Union members vote down second tentative agreement.
Oct. 14 -- Union issues 72-hour strike notice.
Oct. 23 -- Per Gov. Jerry Brown's request, an Alameda County Superior Court judge orders a 60-day cooling-off period, during which the union cannot strike and the agency cannot lock out workers.
Dec. 10 -- Union files court challenge to AC Transit's route and schedule changes set to go into effect on Dec. 15, saying they violate the terms of the cooling-off period.
Dec. 11 -- Alameda County judge denies union's request for an injunction.
Dec. 13-17 -- Contract talks scheduled.
Dec. 22 -- Cooling-off period ends at 11:59 p.m.
Source: Bay Area News Group research