suggestions please - bad ideas for reducing car pollution?

[ChemicalChaos]

Morning all,

I'm doing a little research for a presentation, which for various reasons is going to be on ideas that aimed to reduce car pollution but which turned out to be very bad in hindsight.
Current ideas listed are:
leaded fuel - better efficiency through higher octane, but obviously poisonous
city diesels - 'nuff said
fuel cells - hydrogen production, greenhouse gas potential of water vapour,
hybrids - production and disposal energy intensiveness
carbon composites/fiddly electronic management - as above
biofuels (1st gen) - carbon neutral but cause food crises

this being PH, does anyone please have any other interesting suggestions to touch on?

thanks!

[ChemicalChaos]

thanks chaps,

I was more on about "scientific advancements" than behavioral changes however

[ChemicalChaos]

Thanks for all the suggestions everyone. In the end I managed to go way over the word count with just the few existing ideas, but I have worked the essence of some of your suggestions into my points in the main text.

You might be interested to see the final product, so here it is!
https://docs.google.com/document/d/1-Jm53X0jdzlbFU...


The actual brief was to write 3000 words on a topic of any choice, that answered a question to do with the uses of green/renewable/environmental chemistry. I appreciate that to a car enthusiast, some of the points you'll see argued are very tenuous - but having committed myself to the title without having done much research, i had to work what what I had!