After winning passage of a third bond issue in seven years, Los Angeles Unified leaders said Wednesday they are ready to move forward rapidly on their massive school construction and modernization money.

Among the first things on their agenda will be to buy land to build a promised 50 new schools, which much of the money will go toward. The district also has to hold a number of public meetings so that it can design the right kind of schools to meet specific community needs.

In all, the process will take at least four years before students will see relief from the overcrowding that now plagues the 740,000-student district.

Some $3.87 billion of the total bond money will come from local Measure R, which voters passed by a wide margin Tuesday, and $1.5 billion will come from Proposition 55, a state bond issue that squeaked by with just 50.6 percent of the vote.

School leaders are just grateful they don't have to slash their ambitious school construction and repair plans which looked like a real possibility late Tuesday when support for Proposition 55 was teetering.

"I just said, thank the Lord," Glenn Gritzner, special assistant to Superintendent Roy Romer, said after seeing the final results early Wednesday. "Now we know we can deliver on everything."

A dozen of the 50 new schools are expected to be built in the San Fernando Valley. In addition to school construction and modernization, local Measure R also earmarks money for full-day kindergarten, library books and charter schools.

Coupled with the state money, funds from Measure R are designed to allow more students to attend school on a traditional nine-month calendar. Educators will have to make tough decisions about which schools to relieve first, officials said.

"We have to make some policy decisions about how we prioritize the seats," Gritzner said.

The new bond money takes the district's school construction program to $15 billion, making it the largest in the nation.

"The key is to prevent any arrogance of power and money feeling like the people have made you a billionaire when what the people really said was keep working, building our schools and repairing our schools. The job's not done," Trustee David Tokofsky said.

The Los Angeles Unified School District cannot squander this money, he said. The LAUSD must insist that its Office of the Inspector General is equipped to conduct audits, that its oversight committee is strong and independent and that its school board demands accountability, he said.

Some critics say the district-led oversight efforts are pointless. To be effective, oversight would have to be driven by an outside agency, said Carlos L'Dera, founder of Parents Demand, a watchdog group of LAUSD parents.

"The passage of 55, especially, and Measure R is a total waste. School districts have proven themselves to be totally irresponsible financially," he said. "Right now, the money is not going where it should be to the students and the classroom. It's going to the hierarchy."

Tom Rubin, a member of the LAUSD Bond Oversight Committee, said he understands residents' concern.

"It is a lot of money, and it's their money," he said. "But the job of the oversight committee is to report back to the public on how things are going, whether it be good, bad or somewhere in between. I will be watching everything like a hawk."