PROVIDENCE, R.I. — The fate of Rhode Island’s landmark pension overhaul — a model cited in other states wrestling with escalating retirements — now hinges on the votes of the same government workers and retirees who sued to block the law.

Thousands of teachers, firefighters, police and other state and municipal workers and retirees are voting on a proposed settlement in the legal challenge to the 2011 pension law, which raised retirement ages and suspended pension increases.

The proposed settlement offers retirees a modest pension increase — $500 — with the promise of additional increases sooner than the current law. But it retains most of the sweeping changes approved by lawmakers — and the billions of dollars the law is expected to save the state and its municipalities in coming decades. The settlement must be approved by public workers, retirees and state lawmakers. If the proposal is rejected at any stage, the lawsuit would continue.

Rhode Island had one of the most troubled pension systems in the nation before lawmakers passed the overhaul in a special legislative session. The Rhode Island Retirement Security Act was designed to save an estimated $4 billion for the state over the next 20 years.

Many of the 66,000 state workers, teachers and municipal workers and retirees covered by the state retirement system complained that the changes amounted to broken promises and an unconstitutional change to their benefits. The legal challenge to the law was the subject of closed-door settlement negotiations for more than a year, while the law was heralded — and derided — across the country as other states looked to address their own pension problems.