"W K" wrote in message
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"Nick Finnigan" wrote in message
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"W K" wrote in message
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london-research speed data used to be, which
showed pollution per km is best around 45mph (except NOx)

Perhaps because in london, any road where you are going less than 40 is
horrendously stop start.

Even supposing that the research was London specific, where
could you average 38mph and be horrendously stop start?

Are there many roads within london where you can do an average 38?

I don't know.

I was going to say 30.
I'd still be interested how they got the information.

Unfortunately, www.london-research.co.uk seems to have
disappeared of the face of the world.