How Do Transit Agencies Decide on What Vehicles To Purchase?
The biggest capital expense for transit agencies is buses ( recall the difference between capital and operating funding ). As buses in the United States are expected to last at least twelve years before being replaced, poor decisions in the coach procurement process are not only costly but can doom the agency for years. Agencies make the purchasing decision based on the following factors: size, propulsion system, high or low floor, and manufacturer. Recall in Part 1 we looked at size and in Part 2 we looked at propulsion system . In this part we will examine the choice of high or low floor and manufacturer.
3. High or Low Floor?
Until relatively recently, all transit buses were of the high-floor variety. This meant that patrons had to climb two or three stairs to enter or exit the bus. In an attempt to make boarding and exiting the bus easier for people with disabilities, low-floor buses were developed. In a low-floor bus, entering and exiting is level with the curb. Although most low-floor buses have a raised back part which requires climbing stairs to access, some newer low-floor buses are all at the same level.
Although low-floor buses are indeed much easier to access for senior and disabled people (see below on lift-equipped buses), the lower floor means that seats cannot be provided above the front wheel well (and the back wheel well as well, if the bus is of the all low-floor variety). From a logistical standpoint this means that a low-floor bus cannot hold as many people as a high-floor bus, which means that if introduced on crowded routes with no change in headway that crowding can occur. In fact, the reduced capacity of low-floor buses is the primary reason why I believe that low floor buses need a lower load factor .
Another benefit of low-floor buses that I have not seen discussed in academic transit research is that low-floor buses should result in faster vehicle boarding and alighting due to the lack of stairs. Although it would be very difficult to do so because of all the confounding factors, it would be interesting to compare running times of a route before and after the deployment of low-floor buses.
A final potential benefit of low-floor buses that I also have not seen studied is whether the low-floor vehicle, by virtue of being closer to the level of the passenger, is viewed more favorably by the passenger, perhaps because it is more welcoming than a high-floor bus.
Although there are many manufacturers of buses in the world, the fact that any buses purchased at least in part with federal government money (which is the vast majority of transit buses in the United States) have to be manufactured in the United States has meant that for American transit agencies there are a limited amount of manufacturers to choose from. The three largest suppliers of buses to the American transit market are New Flyer of Winnipeg, Manitoba; Gillig of Hayward, CA; and North American Bus Industries (NABI) of Alabama. Some transit agencies also purchase buses from Ontario-based Orion (now owned by Daimler-Chrysler) and St. Eustache, Quebec based Nova. This "Buy America" rule is the primary reason why New Flyer of Winnipeg, Manitoba opened a factory in Crookston, Minnesota; and Nova Bus of St. Eustache, Quebec opened a factory in Plattsburgh, NY. AC Transit of Oakland, CA was able to purchase VanHool buses manufactured in Holland only due to clever moving around of government funds to ensure that no federal funding was specifically earmarked for the bus purchase.
Because so much of a transit bus is customized and provided by third parties, there is little substantive difference between bus manufacturers. For example, engines are usually made by either Cummins or Detroit Diesel, regardless of the bus manufacturer; and transmissions are usually made by either Alison or Voith, again, regardless of the bus manufacturer. For this reason, price has become a very important determination in what bus to go with, with Gillig tending to come in at a lower price than New Flyer with the other companies in between.
From a transit agency perspective, cost is also minimized by picking one manufacturer and sticking with it. Having all vehicles produced by the same company enables agencies to save on warehouse costs, since they do not have to stock three different types of the same part for buses made by three different companies, and maintenance costs, since their mechanics only have to be trained and keep current on one bus. Most agencies seem to be heading towards fleets made up of vehicles from only one bus manufacturer, much to the chagrin of transit fans.
5. What About Lift-Equipped Buses?
Since 1990, all buses purchased in the United States with government money for public use are required to be accessible to persons with disabilities. In fact, as described above, one reason why low-floor buses have become almost the universal bus of choice is that the ramps on low-floor buses, which unwind to allow level boarding, have much fewer maintenance problems than the lifts on high-floor buses. By the end of the decade, all new buses in Canada will also have to be accessible to people with disabilities. Please see here for more information on how the Americans With Disabilities Act affects what kind of vehicles can be purchased .
In these three articles I have described what I feel to be the most important criteria that transit agencies use to determine bus purchases. Of course, there are many other factors, including choice of engine and transmission, that I do not have the technical expertise to assess. I can tell you one thing, though: transit agencies are generally very conservative, and loathe to be the guinea pig that tries a new bus company or propulsion system. This perhaps justified conservatism helps to explain why it has taken so long for new kinds of buses, including the first buses with ramps, low-floor buses, and buses with alternative propulsion systems, to gain acceptance in the industry. New buses are expensive, and due to the amount of time they will be around direct the near term future of the transit system. It is only natural that transit agencies spend a lengthy period of time exploring their options.