OC Transpo Active Fleet Size

 

	1982	1987	1992	1997	2002
Articulated Buses	21	134	161	114	171
Percentage of Total Active Fleet	2.7	16.3	19.4	14.4	18.7
Ratio of                                    Standard Equivalent km : Bus km	0.99	1.06	1.09	1.07	1.09

 

The authors note that the statistic published by OC Transpo, “Standard Equivalent km,” is based on the relative size of vehicles in the active fleet - and does not directly reflect the relative share of revenue km operated by articulated buses. Personal observations at 1992 and 2000 suggest that the share of OC Transpo peak-period service operated by articulated buses was reduced during this interval.

Articulated buses utilize operator (driver) labor more efficiently than standard buses because of larger vehicle size, and so achieve greater productivity. However, articulated buses cost more to operate; various cost elements include greater fuel consumption and higher maintenance costs (UMTA 1982, UMTA 1984). Net result: articulated buses cost about 25 percent more to operate per revenue service hour (RSH) than standard buses. Early planning studies often assume equivalent operating cost per RSH for standard and articulated buses, but this does not reflect results from actual service.

The relevance of research by the U.S. Urban Mass Transportation Administration from the early 1980s to the current generation of articulated buses has been questioned. However, the comparison of interest is not between today’s articulated vehicles and those built 25 years ago, but between contemporary articulated and standard vehicles. For this purpose, the UMTA findings remain relevant. Despite design improvements over the past 20 years, operation of articulated buses still costs more per RSH than operation of standard buses - simply because articulated buses are larger, heavier vehicles with greater passenger capacity. Comparative specifications suggest that recent articulated buses might have greater mass per unit of length than earlier vehicles, as the result increased durability and increased power. This in turn would lead to relatively greater fuel consumption per RSH by comparison with today’s standard buses. The difference in operating cost per RSH might be greater than the 25 percent found by UMTA.

A common planning assumption is that bus operating cost per RSH does not vary with operating speed. This is not correct. Given an increase in revenue km per RSH, fuel accounts for a relatively larger share of operating cost per RSH even if fuel economy (km/L, or mpg) does not change. This occurs simply as a consequence of the increased number of km per RSH. Fuel accounts for a relatively small share of total operating cost per RSH, but this “small share” is not “fixed” and positive changes exert upward pressure on unit operating costs.