Daniel Barlow said:[ Hope I've got the attributions right here ]
Quoted message said:Paul Smith <[email hidden]> writes:
Quoted message said:Quoted message said:Gonzalez <[email hidden]> wrote:
Quoted message said:Quoted message said:Quoted message said:And all things being equal, slower speeds are safer speeds.
Quoted message said:Quoted message said:All things can never be equal. Somehow the speed was changed, and not by magic or theory. Anyway
the other part isn't true either. Imagine trying to do a "nice safe 30mph" in lane 3 of a busy
motorway. Many researchers have found a U shaped curve of accident risk with the fastest and
slowest drivers at elevated risk of accident.
Quoted message said:With the exception of very large vehicles, the speed limits are the same for everyone. Nobody is
forcing these slower vehicles to travel more slowly; the strong probability is that they're going
as fast as they judge to be safe (perhaps they're not confident drivers, or they don't know the
road, or they just have poor judgement). I don't think you can claim these accidents as due to
inattention.
The time that inattention is likely to arise is if we cause people to drive at a speed which they
properly judge to be well under the speed they would otherwise have properly chosen. There's quite a
bit of it about.
Quoted message said:Quoted message said:Quoted message said:>>> lower speed (of cycling) is inherently less demanding
Quoted message said:Were all other thing equal, I'd agree, but as you point out, they can never be.
Accepted.
Quoted message said:For one thing, the cognitive load is probably mostly a function of _perceived_ speed.
I dispute that. It's a function of "time to react". When travelling near or above maximum safe
limits there's a dramatic and obvious increase in workload and concentration, as one strives to take
account of all that's happening. At such speeds; (which I never recommend for road driving by the
way) One might have a sensation of being "on the edge" and concentration is critical.
Below this potential "ragged edge" there's a sliding scale and as speed tends towards zero, so does
the requirement to concentrate.
Quoted message said:In a car at 25mph, the suspension filters out vibration from the road surface, the enclosed body
filter out wind noise, the mass of the car ensures that crosswind is not really an issue and the
momentum of the car tends to mean that minor gradients are not nearly as obvious. On top of which,
I'm not actually _doing_ very much. On a bike at the same speed, I have skinny tyres that transmit
every bump from the road, I'm being buffeted by the wind and by the draft from passing vehicles,
every change in gradient gets noticed, and I'm busy turning my legs around at 90+ rpm. I don't
think the situations are comparable, let alone equal.
I don't think the factors you cite have much to do with the sort of concentration we were talking
about. I was talking about directing concentration towards developing events ahead. In the case
of what might be termed "concentrated cycling" it isn't unusual to see racing cyclists looking
down while they concentrate on delivering maximum output. Are these guys paying attention to the
road ahead?
Quoted message said:Quoted message said:Quoted message said:Do you think a driver could do the trip safely in their Ferrari in 1.5 hours at 160 mph?
Quoted message said:Quoted message said:Sometimes, in certain circumstances, yes, I do think so. It might be possible to find a quiet
autobahn, or maybe we could do it at a test track. There's no inherent danger in speed. The
danger only arises when the speed is inappropriate for the conditions.
Quoted message said:A jet pilot could probably do the trip pretty safely at 300mph in something less than an hour, if
not on the same (or any) road. I don't think these examples are adding anything.
Agreed.
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Paul Smith Scotland, UK safespeed.org.uksafespeed.org.ukOpen ↗ please remove "XYZ" to reply by email speed
cameras cost lives