| Topic: | Re:Come and enjoy the lovely air in Putney High Street - I don't think | |
| Posted by: | Richard Hodges | |
| Date/Time: | 25/01/10 14:36:00 |
| Like-for-like, diesel cars are allowed about 3x as much NOx put the exhaust. Comparing uncatalysed PSVs with catalysed cars, and you are many factors different. Comparing occupancy rates - well maybe elsewhere, but on PHS? Seriously? (FWIW, 2 in a car, better than a laden bus). BTW, we also saw this with the Congestion Charge zone - Noxious emissions actually rose in certain parts, because the catalyst-equipped cars weren't there to mop up the mess crated by the psvs and hgvs. Position will have a huge impact. Power demands for fixed speed are a tiny fraction of those for acceleration (for real world speeds). Peak cylinder pressures (the key pre-cursor for NOx) go through the roof. The problem is exacerbated for PSV & commercial vehicles - they have to dig deeper into theor power reserves, and then pump it out the exhaust with less treatment. Somone mentioned eye watering, which is more likely to be ammonia - which as we learnt a couple of years back can result from badly maintained particulate traps on... the buses. This may surprise you, but I'm not anti-bus, nor defending cars at any price. My annual mileage barely escapes three figures. But what we have had is an indoctrination, and people now automatically assume that the car/driver is at fault. This time, I'm suggesting that there are far more likely reasons for the claimed problem. If you start from the wrong assumptions, you're unlikely to get the right answers. We should have; - Second even third generation green Routemasters (multifuel, hybrid, regen braking) on the roads already. The opportunity was clear and technology ready 15 years ago. - Far more efficient urban vehicles available for sale (oddly enough, the world-leader is being developed just down the A3, but you won't have heard of it, because it uses petrol). |