Also worth taking note of - what are the trade-offs people are willing to make regarding speed against accidents? If no-one was allowed to go above 5 mph (including joggers, cyclists, cars) serious accidents would be reduced to near zero. I suspect that very few people are willing to go this far down the trade-off route though.
Another solution would by barriers between pavements and roads with a few designated crossing places. Once again, few people would like this solution..
5 pages in and we're already on the
"They'll bring back the man with the red flag next!!!11111"
Not bad.