The message
from "dennis@home" contains these words:

http://petitions.pm.gov.uk/85-mph/?
What's the significance of 85 mph?

1.5 x the energy if you crash?
1.5 x the stopping distance at 70 mph?

Same energy, since that is the speed the bulk of the traffic is moving at
now anyway.

No it isn't.
Most of it is below 70.

Only where it is congested.

Where traffic is flowing feely I find that the majority of cars and
vaans on motorways are doing between 70 and 90. I don't think raising
the speed limit on motorways will do much other than make a higher
proportion of motorists at least temporarily lawful.

--
Roger Chapman