Mind your manners, mother always said. For far too many commuters, the lesson never took. It's called "personal" grooming for a reason.

This week the MTA is taking its "Courtesy Counts" ad campaign above ground, placing in all 4,600 city buses the signs that have graced nearly half the system's subway cars for the past two months.

Those placards remind riders of the do's and don'ts of using public transportation. Mostly, it's commonsense stuff, but it needs to be said because common sense so often is ignored on our subways and buses.

Courtesy also is more important than ever because more of us crowd into the system than ever before. Daily subway ridership topped 6 million for the first time in 2014 -- and it happened on 29 different days. Bus ridership keeps ticking up, too, and now exceeds 2.5 million a day.

With that many bodies packed that tightly, breaches of etiquette become ever more offensive. The MTA's bus campaign is similar to its subway crusade in focusing on behaviors that make the ride faster and more comfortable for everyone -- for example, don't crowd the front of the bus, move to the rear, stay clear of doors, keep the sound down, don't eat and drink, and keep your feet off the darned seats and armrests (cleanliness counts, too).

And, oh yes, please do offer your seat to an elderly, disabled or pregnant person. It's amazing -- and disconcerting -- how much pushback that one gets.

MTA officials say the feedback from the subway campaign has been positive, while acknowledging it's too early to tell whether the signs are actually changing behavior or reducing the number of complaints lodged with the MTA.

One of our favorite messages in the new bus campaign is this one: "Stay Tuned Into Your Surroundings." In other words, don't block the flow.

We're packed like sardines and often late. Face it: Our mothers are right. Manners matter. Make it easier on yourself.

We'd love to hear your suggestions on

bus etiquette. Email us at am-letters@am-ny.com

or tweet to @amNYOpinion.