Riding the TTC can be a challenge for anyone, but it's especially strenuous for those carrying precious cargo – like a bag filled with electronics, or a small human in one's belly.

Pregnant women, like seniors, people using mobility devices and people with disabilities, have reserved seating on all TTC vehicles, in the blue chairs.

If every blue chair on the bus, subway or streetcar is occupied, it's only common courtesy for able-bodied individuals to stand and surrender their regular seats for those who actually need to sit.

Streetcar driver just announced over the speaker "someone to get out of their seat" for a pregnant woman and it was the best #TTC #Toronto

— Kelsey Rutherford (@kjruther) September 21, 2017

There are signs all over the place to remind TTC passengers of the blue seat rules, and people who violate them can be fined up to $235.00.

Regular seats are a little bit trickier, though. Passengers are trusted to use their own judgment when it comes to moving (or not moving) for a pregnant woman. When they make the wrong call – and it seems like a lot of people do - it's not a good look.

Disgusted by the man who cussed out a women who requested a seat for a pregnant lady standing next to her on the #ttc this morning. Even more shocked by all the people sitting down who didn’t offer their seat... unbelievable Toronto.

— monicaa__ (@Monhanna__) December 18, 2017

Yesterday, a TTC passenger reported seeing someone cuss out a fellow passenger for requesting that he move to accommodate a pregnant person.

Last week, someone on Twitter said that she – at six months pregnant – was pushed by another woman on the streetcar who simply wanted to sit down.

To the woman on the packed King streetcar who pushed me aside at 6 months pregnant so that she could sit down instead of me: may you have a wonderful day. I hope you enjoyed the ride. #karma #TTC #courtesy

— Gabriela Gonzalez (@GabrielaGS_) December 13, 2017

There are dozens of similar social media complaints to be found from Torontonians in recent months – and tons more from all over the world.

In an effort to spark more civility among its riders, Tokyo's transit authority just rolled out an app to help pregnant women find seats on the subway.

Pregnant passengers in The U.K. can order "Baby on Board" badges to wear while expecting, and Korea's "pink light" campaign gives pregnant woman special sensors to activate lights on reserved seats when they board subway trains.

The is nothing worse than starting your day with 200 ignorant people on a streetcar who would not get up for a pregnant woman! #TTC #509

— Elena SC (@Elena_SCs) November 28, 2017

Toronto already has the blue chair program, but TTC spokesperson Stuart Green says there's even more to come in terms of making transit more accessible – and riders more civil.

The TTC has been working with an advisory committee to develop a program similar to one in London, in which people who need seats can easily let others know by wearing a badge or button.

"The priority seating is there for people who need it," said Green. "That includes people with what we would call visible and invisible disabilities."

If you have an invisible illness, you could apply for a @TfL 'Please Offer me a Seat' badge.
Find out more: https://t.co/r9f4Br5qcR pic.twitter.com/jydajQiXko

— Healthwatch Wands (@HWWands) July 6, 2017

Someone who has really bad vertigo, for instance, might need to sit down on the subway to avoid getting sick, but you wouldn't know it to look at them.

Similarly, a woman in her first trimester may not look pregnant yet, but could be dealing with nausea, vertigo and a host of other physical issues that make standing on the bus uncomfortable or even dangerous.

The new program will be introduced sometime in 2018, and "will help people self identity in terms of needing a seat," says Green.

In the meantime, "common courtesy dictates the use of those seats" – so be courteous, Toronto.