On March 1st, a new law  in New York goes into effect, strengthening the freedom of employees to form labor unions at hotels or convention centers run or funded by state authorities, a dramatic victory  for hotel workers in the state. The law has specific language  requiring that hotels or convention centers where state public authorities have a substantial proprietary interest include a "labor peace agreement" with hotel unions in the state in exchange for the unions agreeing not to strike for five years. The law follows a similar executive order  by the Governor approved last year.
Such "labor peace agreements" laws, also often called Project Labor Agreements (PLAs), have become increasingly common in recent years, sometimes negotiated by state and local governments on a project-by-project basis but also required for particular categories of projects. A major expansion of the Los Angeles International Airport includes a PLA  that requires neutrality by employers and recognition of unions when a majority of workers sign cards asking for recognition. Hartford  and the District of Columbia , for example, also have general labor peace ordinances.
At the federal level, President Obama's Executive Order 13502: Use of Project Labor Agreements for Federal Construction Projects  encourages -- although does not require -- federal agencies to use PLAs on federal construction projects in excess of $25 million.
The advantages of such labor peace agreements are clear. As this report  by the Cornell School of Industrial and Labor Relations notes, it makes costs predictable and prevents delays and disruptions, while preventing the "'under the table' cash payments, ignoring wage, hour and tax laws, and intentional misclassification of workers as independent contractors" that has become too common industry practices.
Text of Labor Peace Portion of 2009 New York Public Authorities Law 
American Prospect - Good Jobs, Healthy Cities
Cornell School of Industrial and Labor Relations - Project Labor Agreements in New York: In the Public Interest
Office of New York Governor - Labor Peace Policy Directive
Labor Peace Now - The Hartford Labor Peace Ordinance
District of Columbia Hotel Development Projects Labor Peace Agreement Act
White House - Executive Order 13502: Use of Project Labor Agreements for Federal Construction Projects