A Bronx lawmaker wants to put radar signs that display how fast drivers are going near every school in the city if speed cameras aren’t restored by Albany.

Councilmember Mark Gjonaj (D-Bronx) is introducing legislation this week that would require speed signs by Oct. 31 at any school building with more than 250 students.

His office says that because the signs are cheaper than speed cameras, they can be rolled out to about 1,200 buildings rather than the 140 where the cameras were operating until last week.

All but 20 of the cameras were shut off last week after the state Senate failed to pass legislation extending their use — and, without action, the remaining ones will expire in late August.

But city Transportation Department officials say the signs aren’t as effective as speed cameras and aren’t suitable for every location.