Average speed yes, but I doubt anyone is doing 8mph.
It’s likely they drive closer to 20 mph (needing a larger safe distance) then stop at lights (needing no safe distance, but probably 3-5m if you have the driving school of thought to be able to have an exit at all times). Then there is all the space occupied by the intersections themselves. These would further space out cars, bringing the average length of X cars higher.
These are all guesses based on my local knowledge, I have been to London in close to a decade, and I did not drive there.
Generally guidance for “safe” following distance is to be able to stop before you hit a car that is also stopping with the assumption that the car ahead is stopping at the same rate. So 2 seconds of headway between cars (roughly reaction time alone). Obviously this does not give enough time if the car ahead has a head on collision or similar (but the third car will collide at lower speed and the fourth might stop).
Most traffic is a little closer together than this (hence the prevalence of pile ups), but there is also uneven speed and gaps at traffic lights and similar
5 m/s is 18kph or ~11mph.
40kph safe stopping distance is 26 meters dry, 30 meters wet. I can’t even find data below 40 kph, but 10m would be reaction time alone (no bake time)
The average speed in London is 8 mph overall, taking traffic into account.
Average speed yes, but I doubt anyone is doing 8mph.
It’s likely they drive closer to 20 mph (needing a larger safe distance) then stop at lights (needing no safe distance, but probably 3-5m if you have the driving school of thought to be able to have an exit at all times). Then there is all the space occupied by the intersections themselves. These would further space out cars, bringing the average length of X cars higher.
These are all guesses based on my local knowledge, I have been to London in close to a decade, and I did not drive there.
deleted by creator
Generally guidance for “safe” following distance is to be able to stop before you hit a car that is also stopping with the assumption that the car ahead is stopping at the same rate. So 2 seconds of headway between cars (roughly reaction time alone). Obviously this does not give enough time if the car ahead has a head on collision or similar (but the third car will collide at lower speed and the fourth might stop).
Most traffic is a little closer together than this (hence the prevalence of pile ups), but there is also uneven speed and gaps at traffic lights and similar