The 25-day countdown to a new, slower 25 mph speed limit in the city began Wednesday with the start of a driver awareness blitz, lending a boost to the mayor's Vision Zero agenda.

Drivers will start seeing more signs, getting fliers and hearing radio ads -- including one featuring Giants quarterback Eli Manning.

"Many in New York are largely unaware of what the city's default speed limit is, let alone that it's now going to drop to 25 mph," city Department of Transportation Commissioner Polly Trottenberg said at a news conference in Prospect Heights.

"We are really trying to implement this new default speed limit thoughtfully and carefully," she added. "It is not a one-sized fits all."

The new limit will go into effect on Nov. 7, but it won't include every city street, Trottenberg said.

Amy Cohen became a street safety advocate after her 12-year-old son, Sammy, was killed in Park Slope last year. While there may be drivers who see a cash grab for the city, Cohen said a $30 ticket is worth the change in behavior.

"They are violating the law and the law is designed to save lives," Cohen said. "New York is a big city and there are a lot of streets and there's a lot to enforce... they have a big job ahead of them and they still have a lot to do."

Drivers entering the city from major highways and bridges will immediately see the new signs, officials said. Meanwhile the Taxi and Limousine Commission will run an awareness campaign for its drivers through November.

But unlike the flurry of summonses that have been issued this year, the DOT educational offensive will not be met with an NYPD ticket blitz.

So far this year there have been 27,329 speed enforcement summonses issued on local city streets, an increase of more than 90% compared to the same time period last year. There were an additional 26,482 tickets for failure to yield, a jump of more than 147% from the same time period in 2013, according to NBYPD Chief of Transportation Thomas Chan.

"There is some discretion on the officer's part in terms of issuing summonses," Chan said. "There will not necessarily be a ticket blitz that will hit on that Nov. 7."

Trottenberg said the new speed limit goes into effect as the default on roads without a posted speed limit, which make up most of the city's streets.

This summer the State allowed the city to cut the limit on streets -- without signs -- to 25 mph from 30 mph, a key part of Mayor Bill de Blasio's Vision Zero agenda.

Speeding and failure to yield to pedestrians while turning are the top causes of injury and death on the streets, authorities have said. Advocates who have pushed for slower car speeds say drivers get more time to react and chances of severe injury to someone hit by a car drops.