I have done some homework about the process for negotiating teachers' contracts. According to the CTA, school districts and teachers' unions are required to negotiate a new contract once every three years.
According to Trevor Knaggs, the president of the Association of Pleasanton Teachers, the current contract between the APT and the PUSD expires in the summer of 2010.
This is the reason that the current salary schedule is in place -- it was negotiated two summers ago, and once the contract is finalized, it is not possible for one party to the contract to unilaterally reopen negotiations.
Cost of living adjustments are apparently not negotiated as part of the 3-year contract, but are set annually.
The recent memorandum of understanding between PUSD and APT that decreases the number of paid professional development days from 3 to 1 was established by mutual consent.