Former Mayor Richard Riordan's Save Los Angeles campaign was working to gather 300,000 signatures by Dec. 28.
But spokesman John Schwada told the Los Angeles Times (http://lat.ms/QGKPuu) on Monday that Riordan concluded the deadline cannot be met.
The measure was aimed at cutting the pension benefits of existing city workers and requiring new workers to rely on a 401(k)-style retirement plan. The proposal was harshly criticized by unions.
Riordan says in a statement that he will explore other pension reform options.
He is asking the mayor, City Council and union leaders to work with him to save the city from bankruptcy and drastic cuts to public services.
Information from: Los Angeles Times, http://www.latimes.com