Explores basic theories and principles of an effective transit system.
Access or Mobility?
Every transit system must find a balance between conflicting priorities to best meet the needs of its users. It is impossible, to provide efficient, cost effective, service between all possible locations at all possible times. The most basic challenge is between access (how easily travellers can get to and use transit) and mobility (the ability of transit to move people from one location to another).
A highly accessible system travels close to every home and business but stops frequently and travels slowly. A system that focuses on high mobility travels quickly, and can move many passengers, but only serves major corridors and destinations. Of course, there is a lot more to it than this and so the choices become more complicated.
What is the purpose of transit?
In order to find the balance between access and mobility, it is important to find out what users expect transit to do. Four important parts of this are:
- Should transit be more for those who use it, or is it meant benefit the entire community?
- Should transit move as many people as possible or focus on those who need it most?
- Should transit focus on the current needs or long term goals?
- Should we spend more on transit? Or less?
How should transit service be provided?
Once the purpose of transit is clear, decisions can be made about the types of service to provide. Again, trade-offs will need to be made. The type of service can be thought of as having four parts:
- Should transit connect as many places as possible or focus on the most popular and important connections?
- Should transit provide direct service without transfers or should service be standardized and well connected?
- Should transit be focused during the busiest time periods or provide consistent service?
- Should transit focus on operational performance or providing the best experience to customers?
How does transit connect across the city?
In order to connect many locations throughout the city, transit uses “local” lines that travel slowly and stop frequently and “express” lines that travel much faster to connect distant areas of the city. These lines all connect together to form various types of networks. Some networks resemble a grid while others “radiate” from the center point, and may also include “orbital” lines that make a ring around the city. Some cities, like Edmonton, have hybrid networks with both grid and radial lines. No one network type is always preferable, instead each works better for some cities than others. The type of network used is dependent on where people travel.
Which transit modes should be used?
Currently Edmonton uses buses and LRT, but these are not the only modes of transit that can be used. Others include bus rapid transit (BRT), streetcars, and regional rail (metro) lines. Each mode has pros and cons that make it better for some uses than others. For example, while LRT is great at moving many people between popular destination, it doesn’t work well in quiet neighborhoods with stops at every block.
The difference between BRT and LRT has been discussed a lot recently, but neither is always better than the other. A single LRT train can hold many more passengers than a bus, but BRT is cheaper to construct. Because of this, LRT usually works better for very busy routes, but if there aren’t enough riders to fill the trains, BRT might be a better choice. It is possible to build a BRT and then later upgrade it to an LRT, although doing so is costly and means shutting down the very busy BRT until the LRT is completed, which may be several years.
What are some of the delivery models that could be used?
The simplest model is to provide Direct Service where transfers are not required. Unfortunately, in large areas with many destinations, this type of network is very inefficient. ETS does use a number of direct routes that operate in special cases where the demand warrants this service.
Edmonton’s transit system was originally designed as a Hub and Spoke model on a Timed Transfer Network. In this model, many routes converge at the same time at a single “hub,” allowing passengers to transfer between routes without delay. This model provides both good coverage and, ideally, passengers can easily transfer to express routes to get across the city. However, this model requires most passengers to transfer and any delays can cause passengers to miss their transfer.
The Frequent Transit Network model is another system that provides high frequency service (15 minutes or less) along important corridors, with transfers taking place at a variety of locations along these corridors.
This model ensures short waiting and transfer times, even if schedules aren’t synchronized. A number of cities have adopted this model and have found that the high frequency can reduce travel times, while the large number of transfer points can make it easier for passengers to get around. Supporters of this model also claim it increases ridership due to the more frequent service.
The drawback of this model is that it only works where there is a lot of demand. Because of this, most buses run only in popular areas while other areas have little or no service. This can create equality issues, where people who depend on transit are unable to access it.
The City is currently trying to understand which model(s) would work best in Edmonton. The Transit Strategy will help us is to determine what our transit priorities are as a community, how to balance them and what combination of transit models will help us achieve that balance. What’s most important to you in a transit system?