Due to vacancies on the Board of Supervisors before 2000, Brown was able to appoint eight of the board's 11 members. Due to a change in San Francisco's election laws that took effect in 2000, the board changed from at-large to district-based elections, and all seats on the board were up for election. The voters elected a new group of supervisors that ran on changing the city's development policy. Voters also passed a measure that weakened the mayor's control over the Planning Commission and Board of Appeals. The new majority limited Brown's power over the Elections Department, the Police Commission, and extending San Francisco International Airport's runways into the bay to reduce flight delays. In July 2001, the Board of Supervisors overrode Brown's veto for the first time, creating legislation that created the new home ownership option of tenancies in common.