First - How many
people per hour does one freeway lane actually carry?
Here in California, CalTrans has measured that the average freeway lane
at its best carries about 3,000 cars per hour. If
we assume the CalTrans figure of 1.2 people per car that works out to 3,600
people going by per hour. Thus, three lanes at best will
carry 10,800 people per hour.
We are claiming SkyTran
can move 14,400 people per hour!
This is
actually the equivalent of 4 freeway lanes not 3! However,
let's be a bit more realistic and realize that the 14,400 condition assumes 2
People are riding in each two passenger Pod. (This is akin to
assuming 5 people would be riding in every automobile! If we use the same
1.2 people per vehicle that CalTrans uses, then you can rightly quibble we
would only be carrying 8,640 people per hour. If the government discontinued
forcing car pool lanes on us, commuter automobile ridership would probably
be down to 1.001 person per vehicle real quick. We humans like personal
transportation! When commuting to work, we want to go at a
time we choose and we want to go as
directly as possible to our chosen destination. Simple as
that! For the same reasons, SkyTran ridership will
realistically be 7,200 people per hour per lane (which is actually the
equivalent of 2.4 freeway lanes).
HOW??
The more important question one should be asking is just HOW
can we safely squeeze 7,200 SkyTran vehicles per hour
per overhead monorail track lane? That is simple - just use a one half
second spacing interval per vehicle and precision radar controls. There are
3,600 seconds in one hour and 2 vehicles coming by each second equals 7,200!
Automobile traffic is not
that tightly packed because humans need more reaction times
than computers do. Most, not all, drivers follow other cars with a spacing
that they are comfortable with. Normal drivers do not relish focusing their
entire concentration to follow right on someone's tail for minutes or hours
on end. Without any mathematical formulas, whatsoever, we all figure out how
close we can follow and still get safely stopped if something weird
happens just in front of us. We know the vehicle in front of us CANNOT
instantly STOP! We adjust our spacing mentally by simply including a factor
for the distance the other driver would take to stop once we see his brake
lights appear. (You
may have read about a section of a San Diego, California freeway that is
currently being used to test automatic computer driven automobiles. The cars
travel at 65 MPH autonomously - while spaced just feet apart from each
other. The benefit in tightly packing traffic is more people per lane
per hour, which means less congestion, and the elimination of building
more $24 million per mile freeways to carry the ever growing traffic.)
Public
Transportation Braking Laws
Public transportation, such as trains, on the other hand, have to follow
unreasonable braking laws which have nothing to do with the reality of
physics. Trains cannot legally follow each other any closer
than the distance required to make a complete stop. This is
analogous to you having to be completely stopped by the point along
the freeway where the driver in front of you tapped his brake lights.
We all know this point has nothing to do with where you could possibly ever
contact his car. His car cannot stop instantaneously! We all have learned to
sense from assorted little cues whether or not the driver in front of us is
paying reasonable attention or off in la la land (tough to check by looking
directly into their eyes). Years of driving experience allow us to trust
that the person in front will hit the brakes and gradually slow down and not
just go piling stupidly into a stalled truck or whatever.
What do these
train laws have to do with SkyTran?
Mainly, it got us thinking about just what would it take to still
follow that train braking law and keep our high density 1/2
second spacing! If you are traveling at 100 MPH, you are covering 146.7 feet
each second. Another SkyTran could be 73.3 feet in front of you (one half
second ahead). Guess what, we can take great advantage of our SkyTran
MagLev drive unit being trapped inside the hollow, roll formed,
monorail track. What if we include a hydraulic brake (for emergency use
only) that could squeeze against a rib that we also roll formed into the
track (it runs the entire length of the track)? Then, no longer is
emergency
braking deceleration limited by the traction capabilities of rubber tires on
asphalt or concrete!!!
Superior braking has
tremendous safety implications!
If we assume we can let the on-board radar computer take 50 iterations to
detect, confirm and apply this hydraulic brakes (50 milliseconds = .05
second) and we further control the hydraulic squeeze pressure to give us a constant
6 "g" deceleration, we can get fully stopped in a
mere 55.6 more feet. Including the 7.4 feet used up while the computer is
making up its mind, the total distance is 63 feet. This actually meets
the train braking law requirement
- WOW!
Whoa, Man!
Won't my body be wrecked and my brain be scrambled if I am subjected to 6
"g's"??
Hardly! The interesting
reference chart below shows how the "g" levels ordinary humans can
take varies with the kind of restraint system being worn. There are
acceptable "g" level zones where no injuries occur; higher zones
where injury is very probable; and even higher zones where death will surely
be the result. You can readily see that 6 "g's" is well below the
threshold for injury.
This next table gives
the times and distances it would take to slow down (from 100 MPH to a
complete stop) for an assortment of deceleration "g" levels.
Each level is associated with a vehicle and/or condition.
