[sustran] PCU equivalents for NMT in India

[Kerry Wood]

Dear Walter, Colleagues


Some armchair stuff that might help with the rickshaw pcu problem. I have
been trying to establish the effect on road capacity of putting in cycle
facilities, using a range of assumed widths and cycle capacity data from
the CROW manual.

I make the capacity increase of converting a traffic lane to cycle use
about 2.4 times for a 3.0 m lane and 3.2 times for a 4.0 m lane, which
checks out quite well with the Dutch value of 0.3 pcu for a cycle.

For wider lanes it is possible to retain a narrow traffic lane with a cycle
lane alongside. In this case capacity increases are not so large - about 40
% to 2.4 times. The main point is that there is ALWAYS a capacity increase.

A pedal rickshaw driver has three options in traffic (although not all are
available all the time):
-       Keep well to the left, with room for motor traffic further out: the
pcu equivalent is effectively zero.
-       Keep in the motor traffic lane: the pcu equivalent is a bit less
than 1.0 because the rickshaw is shorter than a car: say 0.8 or so.
-       Keep in the motor traffic lane but alongside another pedal
riskshaw: the pcu equivalent is half the above value, or 0.4 or so.

On this basis a pcu value of somewhere around 0.3 to 0.6 seems reasonable,
but 1.5 or 2.0 does not. To get such a high value needs assumptions about a
large gap opening in front of the rickshaw, because it is slow, and somehow
wasting road space, but my limited experience of India is that nothing goes
to waste, road space included. Building in speed differences (which seems
to be implied by having diffrent figures for urban and rural conditions) is
a distortion of the concept of pcus, where a Beetle and a Ferrari both
score 1.0.

Dr Rajeev Saraf says that most traffic is non-car which changes the
picture: if a pedal rickshaw is about 0.4 pcu, then a car is about 2.5 pru
(pedal rickshaw units). It makes sense to use the dominant mode (or maybe
the mode you want to be dominant) as the base line.

Hope this is helpful


Happy New Year



Kerry Wood
Transport Consultant
Phone/fax + 64 4 801 5549  e-mail kwood at central.co.nz
1 McFarlane St  Wellington 6001  New Zealand