TR Circular E-C058_9th LRT Conference_2003.pdf - Florida ...

Demery and Higgins 365
92-ft (28-m) vehicle length]. These PVO figures imply crowding levels higher than reported
anywhere in North America, except on the busiest HRT lines in México City, Montréal, and New
York.
• Ottawa: PVO (capacity) levels of 54 p/v for standard buses, 102 p/v for articulated
buses, and 117 p/v for LRT vehicles were assumed during alternatives analysis (14). This
overstated BRT net capacity by roughly 50% (or more, given PVO observed on-site: 30–38 p/v;
2.3–2.9 p/m). The analysis 1) underestimated BRT service supply corresponding to given
consumption levels; 2) underestimated BRT operating cost and certain capital costs; and 3)
overestimated BRT performance relative to LRT. These problems appear insignificant compared
to nontechnical and political factors which influenced the mode choice (38). However, the
designed maximum of 15,000 phd would require 300-500 vhd, rather than 200 vhd as stated
prior to construction (absent measures to increase peak-period demand for transit services; e.g.,
higher parking or fuel costs, leading to higher peak-period utilized-capacity levels). This appears
impractical with the current CBD distribution facilities.
• Pittsburgh: a capacity analysis assumed 80 p/v for standard buses and a service
supply ranging between 90–150 vhd, resulting in capacity figures of 7,200–12,000 phd (39). The
PVO figure is nearly twice that observed on Pittsburgh’s busways, and observed peak volumes
are 40% to 60% lower than projected.
• San Diego: San Diego Transit Corporation (40) proposed a BRT alternative to LRT,
and projected a corridor ridership increase from 15,000 to 64,000 p/w over 20 years (to 1995).
But the distribution of ridership between peak and non-peak hours was assumed to remain fixed
as ridership quadrupled. Moore (18) made similar assumptions. Such predictions conflict with
actual experience, results produced by modal-split models, and common logic. The increased
ridership generated by BRT or RRT, at least during initial operation, occurs as an increased share
of travel in the dominant market—CBD work trips—is attracted by the new, faster service.
• Seattle: the maximum capacity of CBD transit tunnel, as implied by the parameters
used currently by the operator, is 5,750 phd, based on 125 vhd and PVO equal to 80% of vehicle
seating capacity. The operator states that the 125 vhd figure is based on “more than ten years of
experience with operating the only all bus tunnel with on-line passenger stations in the world”
(10). 125 vhd is nearly 80% greater than the maximum service level that has yet been operated.
Niles et al. (41) and DMJM+Harris (42) estimate maximum tunnel capacity at 13,455
phd, assuming 65 seats per vehicle, full seated loads, and 200 vhd. The associated service supply
is nearly three times greater than that yet operated. These analyses also estimate a maximum
capacity of 15,950 phd, assuming 110 p/v (6.0 p/m) and 145 vhd. PVO and service-supply
figures are double the current levels. Rubin and Moore (1997) state a “theoretical” peak-hour
capacity of 18,000 phd, based on 145 vhd. This implies 124 p/v (6.8 p/m), roughly three times
greater than PVO carried currently by tunnel services.
Seattle’s plan for mixed bus and LRT operation in its CBD transit tunnel include a
maximum service level of 60 bus vhd, 10 LRT thd, and 4-car trains. Six buses would be
scheduled to operate in “platoons” during the 6-min interval between trains. The feasibility of
mixed operation has been demonstrated in Essen, Germany, but with much less than 60 bus/h/d.
The planned bus and LRT service levels may prove impractical when operated over the same
guideway. Another issue, which has not been addressed, is that safety standards for each mode
are not identical. Road vehicles, including Seattle tunnel buses, typically operate beyond the