Sometimes we stare so long at a door that is closing that we see too late the one that is open.Alexander Graham Bell, inventor, 1847–1922
As BRT systems are generally built on busy corridors where there are already many bus or minibus services operating, BRT service planning should start with a detailed understanding of the existing public transport services on the corridor. Sometimes these existing services are already well designed to meet the travel needs of most customers and there may be only minor changes needed to existing bus services to take advantage of the higher speeds along the BRT corridor. At other times the public transport services are poorly matched with the travel needs of customers, and a BRT project creates an opportunity to improve on any preexisting service plan. Modifying these services as part of the BRT project can result in significant benefits to customers.
In order to determine whether existing services are already well designed to serve customer needs, or whether significant improvements could be made, BRT service planning should start with a careful evaluation and understanding of all the bus and minibus services currently using the corridor. The Basic Data Collection section of this chapter outlines how information should be processed and displayed in order to make this clear to both the system planners and the general public.
In most cases, there are significant efficiencies to be gained by optimizing services as part of a BRT project. The following would be indications that the existing services are poorly designed:
The construction of specialized BRT infrastructure along a corridor will introduce three changes to existing public transport operations that will affect the optimization of services:
Chapter 4 (Demand Analysis) describes the process used to estimate the baseline public transport demand on the system, and how to model the demand of a proposed service plan under a given infrastructure. So we have at our disposal tools to evaluate future situations. However, that chapter gives no guidance as to how to decide which service scenarios to model. This chapter provides more guidance on how to decide what sort of services should be proposed and modeled.
If a public transport system demand model has already been created (as proposed in Chapter 4: Demand Analysis), it can be extremely useful in performing the necessary route-by-route analysis and testing the benefits of various service planning alternatives. Running alternative service plan scenarios in the demand model is cumbersome, and creating too many scenarios is very confusing for the public and decision makers alike, so this chapter attempts to help craft better service plan scenarios that can later be tested in the model.
The construction of alternative service plan scenarios is generally done incrementally by first making broad assumptions about the best solution. For this chapter, it will be assumed that the selected corridor has enough demand travelling at slow enough existing speeds that BRT infrastructure is justified. As such, it is reasonable to assume that when planning the services, the bus speeds on the BRT corridor would be BRT speeds, either 20 kph for a standard corridor with stations about 450 meters apart, or the speed of an existing service on the same itinerary late at night or “off-off peak.” Further detailing of the infrastructure can thus be left aside while we consider alternative service planning scenarios. Once basic service planning decisions have been made, Chapter 7: Capacity and Speed provides the tools to refine infrastructure decisions in light of these service planning decisions.