Reports on legal considerations related to APAs clearly show that PTAs are an effective tool for labour relations.  In a 1999 report on the legality of AEPs, the authors stated that AEPs „serve as a productive and stabilizing force in the construction industry.“  This approach is supported by a UCLA study that questioned the results of the Beacon Hill Institute on PLA, which found that in the private sector, the use of ATPs „creates continuity and stability of the workforce in the workplace.“  Community interests are integrated into CWA conditions, often through the inclusion of targeted hiring programs that involve the modest inhabitants of the neighbourhoods around the project with construction quarries. MAPLA presented a detailed and detailed implementation plan that included a committee of port staff, contractors, union representatives and municipal representatives, who assessed each contractor`s compliance with these requirements. Up to 2007, more than 31% of all working hours were worked by residents and local trainees had worked 6.2% of all hours worked. The first uses of Project Labor Agreements in the United States date back to several dam projects in the 1930s, including the Grand Coulee Dam in Washington, the Shasta Dam in California and the Hoover Dam in Nevada.  Modern PLPs developed particularly from those used in the construction sector during the Second World War, at a time when demand for skilled labour was needed, construction unions controlled 87% of the national market and public construction spending had increased significantly in a short period of time. These early PPPs focused on setting standard rates of pay and preventing work stoppages.  Cape Canaveral in the 1960s, Disney World from 1967-71 and Trans-Alaska Pipeline from 1973 to 1977.   At that time and thereafter, the union share of the construction industry declined rapidly as construction users sought open competition. In the 1980s, non-unionized contractors claimed more than 80% of construction work in a large number of companies, with some differences in different parts of the country.  Through the project work agreement and career policy in the construction sector, Metro is working to diversify the workforce of construction projects to improve access to careers and to serve as a catalyst for improving the socio-economic status of minorities and women.
Although the national average for women in the construction sector is less than 3%, metros aims to exceed the target of women`s use 11246. The current average of women`s participation is 3.4%. The San Francisco Public Utilities Commission (PUC) has entered into a project work agreement with local, regional and national construction unions, which covers on-site construction work for a $4.39 billion water system improvement program committed to modernize and strengthen its water system. Construction began in 2007 and is expected to continue until 2015. The agreement itself contains only a general declaration of principle and the obligation to increase the recruitment of low-income people for this construction. Unions and contractors must demonstrate that they have shown good faith in recruiting locally. However, the PUC has developed a detailed plan of local learning and recruitment places for each construction project launched under the PLA.