Environmental Engineering Reference
In-Depth Information
Some key points made in Reference 11 are summarized here for completeness
in this description of an AHS vehicle and guideway concept.
The NLV of 1.12-1.4 m width means the guideway can be very narrow,
thereby actually being capable of location within existing highway medians or
taking over an existing highway lane, but with two-way guideway travel. Fit-
ting two, or even three such guideway lanes within 6.2 m is quite possible and
affordable, even in urban settings.
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PRISM and NLVs in general minimize congestion by facilitating two-way
traffic in the equivalent of a single-lane traffic on conventional streets and
highways. Also, the feature of tandem seating actually provides for greater side
crush space in case of side impact.
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Their low mass improves fuel economy on and off the guideway. On the
guideway fuel economy is dictated mainly by aerodynamics than by vehicle
mass. Therefore, the 600 kg curb mass provides a very economical mode of
transportation when moving at a constant speed. Interestingly, the ratio of
vehicle mass to unit passenger capacity for tandem seated occupants is still
right at 5 kg/kg unit capacity noted earlier in this chapter.
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The previous benefit can be further expanded by noting that in the US, the
average commuter occupancy fraction is 1.2 persons per vehicle. This means that
tandem seating would work out well. Add to this the fact that the driver seat can
swivel 180
, so both occupants could be seated facing each other. Or the vehicle
cabin could be used as a mobile office when on the guideway where safety is very
high. Safety is high in autonomous control because all vehicle operation is con-
fined to a guideway and heading control is via a high speed digital computer and
fast communications to coordinate multiple vehicles on the same guideway.
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Before moving to the topic of power transfer to a moving vehicle, we close this
section on AHS by noting how ingress and egress of PRISM type vehicles are
handled without ever requiring a vehicle to stop. This function is realized using the
3-lane scheme where vehicles entering the guideway approach a crossover portion
that allows existing guideway traffic to either proceed on or exit to the third lane.
The merging vehicles once on this third lane then merge into existing guideway
traffic as shown schematically in Figure 12.5 taken from References 11 and 12.
Figure 12.5 Three-guideway crossover for ingress and egress at high speed
12.3 Non-contacting power transfer
For any type of guideway-based transportation system to function, it is essential
that
the infrastructure includes not only suitable guideways but command,
