You’d think New York’s subways and buses are places people would be sure to close their legs.

But too many men like to take up more than their share of seat space — a nasty habit called manspreading, which the MTA is determined to stop.

Starting in January, MTA bosses plan a public education campaign meant to persuade men to close up their legs and thus take up less scarce seat space on the subway.

One component of the campaign will be a poster that says: “Dude — Stop the Spread, Please.”

MTA board member Charles Moerdler also would like straphangers to stop wearing backpacks, which are a problem for standees on crowded trains and buses.