[sustran] PCU equivalents for NMT in India

[Dr.Rajeev Saraf]

I do not agree with Kerry when he says that the road space does not go 
waste. May be at the intersections when traffic is queued up waiting for 
the green signal.
However, on the link, a de facto segregation takes place between 
motorised and non motorised modes even if the volume of the NMT is quite 
low. Even if there are few rickshaws or cyclists in the curb lane, the 
curb lane does not get used by motorised traffic. In that case, PCU 
values of cycle rickshaws would be very high. This is true for cities 
like Delhi where motorised mode is still a dominant mode. There the PCU 
value of Cycle rickshaw would be quite high.
The point I am trying to make is that the usage of a lane by MT where NMT 
exists ( mostly curb line side) is nearly independent of the volume of NMT.
However, if only pedal rickshaws were using one lane and there was no 
other mode ( under ideal conditions of excellent riding surface and zero 
slope), then throughput could reach 1400 rickshaws per hour per lane 
which would give a PCU value of approximately 1.3 PCUs. However, this 
throught degrades very fast with surface quality and little slopes and of 
course, loading. Keeping these in mind and taking average conditions, a 
PCU value of 3 as suggested by Indian Road Congress (IRC) may be 
acceptable.
I however still question the whole philosphy of PCU in the first place.  


___________________________________________________________________________
Dr Rajeev Saraf                 |
Urban and Transport Planner     |
SENIOR PROJECT SCIENTIST        |      PHONE : 91-11-6858703
APPLIED SYSTEM RESEARCH PROGRAM |      EMAIL : sarafrk at cbme.iitd.ernet.in
IIT DELHI 110016                |      FAX   : 91-11-6862037
INDIA                           |
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On Fri, 9 Jan 1998, Kerry Wood wrote:

> 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
> 
> 
>