I don't know if there are more up-to-date posts on this topic. I followed a '51' plate Passat TDi yesterday which was billowing diesel smoke even under light acceleration round town. I was mildly surprised to see most people in this post adopting a laissez-faire attitude - in the four years which have passed, have attitudes (and the law) hardened? I suppose this car must have an MOT of sorts otherwise, with VNPR everywhere, the owner would surely have had his collar felt by now. He also had one brake light not working. The general condition of the car showed it was clearly a long-term stranger to a wet sponge and I dare say the engine is similarly estranged from anyone with overalls and a spanner. Is it worth reporting* - or am I just becoming Victor Meldrew's clone? (* to whom? Local plod? DVLA?)

This is thread is now very out of date in that there is now much greater public awareness of the very considerable health risks caused by vehicle particulate emissions, especially though not exclusively from diesel vehicles.

So, this is a serious topic, and one for which the replies above are no longer appropriate.

And yes, it is still happening in 2020. I saw a car pumping out black smoke just today, and tried to find out what I could do about it. Because I take the environment and people's health seriously, as many people do these days.

However, it seems that the law currently provides no powers to act in the case of light vans and cars. So nothing can be done apart from see whether the police will act, which I doubt very much in these days of overstretched resources and under funded services.

It's what Yorkshire folk would call "a poor do". In fact a very poor do indeed, that needs something doing about IMHO.

I was thinking about this very same thing myself recently. On Tuesday I saw a town service bus which was emitting a lot of black smoke, the next day I saw the same bus still belching out black smoke. It was a Stagecoach (my ex employer) Optaire bus.

It must have been around 3 or 4 years before I left Stagecoach when we got about a dozen of them (new), so they must be 15 years old by now. Thing is, they were already getting pretty knackered when I left!.

Out of curiosity what was the service regime like on those? In house workshop assumably? The inner town and city buses must live very tough lives. I noticed a lot of last gen London buses had Cummins engines which surprised me but they do have a great reputation in the USA. Cant say smoke ever bothered me, a bit controversial now but I have in previous diesel vehicles enjoyed ‘rolling coal’ !

Not very sure about the servicing regime I’m afraid, and yes, it was all done in house. Us drivers didn’t have much to do with the engineers. The only thing I do remember was regarding the tyres. This is mainly because I was so shocked to learn that the legal minimum tread depth for a bus (truck too presumably) was only 1mm!. But I was told Stagecoach policy was to replace them at 5mm.

I never liked the Optaire’s personally, partly because just they didn’t feel well built, but mainly I just didn’t feel the design of the bus was very suitable for town work. Having the door behind the front wheel meant that at a bus stop between two parked cars you couldn’t get the door close to the pavement. Meaning an old biddy might have to step right down on to the road before stepping back up on to the pavement. On a more traditional shape of bus in the same situation, easy enough to get the very front n/s corner, i.e, the door, over the kerb.