Not sure this advert placement is a good idea:
Not that the exhaust actually comes out of that grill, of course.
And one should not overstate the pollution caused by buses.
Measuring just the CO2 emissions, a diesel bus emits about 1800 grams per kilometre. By comparison a diesel Landrover emits 295 grams per kilometre. At an average 1.2 people per private vehicle, that’s 245 grams per passenger kilometre. So a bus has to be carrying just 8 passengers (which is comparatively empty for a bus) to be more efficient than a diesel Landrover (or about 22 people to be as efficient as a Prius).
The number of people on a bus varies widely. It could be no passengers (just the driver), or if packed it could be 80-100. Some may catch it for many kilometres, some just a few stops.
And of course, you can’t just run the services you know will be packed. You get more people onto PT as a whole if you have a cohesive network, running frequently, and covering the hours that most people travel, so they can rely on it to be there whenever they need it. Smartbus is proof that more buses gets more people using them.
So while the advert (and specifically its placement) above may not have been a good idea, we do need more buses on the road.