PRT - Unsafe at Any Speed
Passenger Safety Concerns Sparks Wikipedia "Reversion War"
An April 5th, 2005 post on a Seattle Yahoo e-mail list reveals an argument PRT Proponents are having about passenger safety. The argument concerns this part of the PRT page in the Wikipedia online encyclopaedia:
Sitting, restrained passengers can tolerate emergency stops
at 6 gravities (59 m/s©ò), a deceleration like a more exciting roller
coaster. At 6 G (59 m/s©ò), 70 mph (115 km/h) vehicles stop in 0.52
seconds, about 27 feet (8 m).
The reason PRT pods have to decelerate so quickly is the pods are supposed
to travel tightly packed on the guideways ( to get the high capacities comparable
to conventinal transit such as BRT or LRT ). With headways measured in inches
or less, emergency braking would cause huge pile-ups unless all the pods lined
up bumper to bumper simultaneously stop on a dime...but, if that were possible,
how would that effect passengers?
Here's two hilarious excerpts from the Yahoo
post by Bob Dunning, President of ATTA, Advanced Transit Association:
> > I believe it to be
seriously wrong. Our own tests show that the peak
> > deceleration for unrestrained seated passengers is 6 m/s/s ie one
> tenth
> > of the quoted level. Even at this level some of our older female
> > passengers (eg my wife) were thrown to the floor. At the deceleration
> > levels quoted such passengers would simply continue out through
the
> > windscreen.
> >
> > I suspect that whoever wrote this got confused between 6 m/s/s
> and 6 g
> > . In combat aircraft pilot are known to pass out at 6 g
*******************************************************
I dont feel we should plan to subject PRT passengers to this (and
> even
> > if this were planned there is the non-trivial problem of
> designing the
> > rest of the vehicle to absorb these extremely high g loads)
> >
> > On the assumption that you agree with my view of this rather than
the
> > Wikipedia version I suggest that one key objective of ATRA should
> be to
> > remove stuff like this from the public domain, where in my
> opinion it is
> > just as, and perhaps even more, damaging than the roadkill site
> >
> > Your views would be welcomed
> >
> > Martin