Timed transfer networks
A way to design public transit for lower-density areas
A while back I was talking to Mike Feaver, who grew up on the North Shore. He mentioned that the North Shore used to have a timed transfer network for its bus routes, which worked well up until the frequency for the 239 increased. I hadn't heard of this concept before: it's based on synchronizing routes at specific nodes (e.g. Phibbs Exchange and Lonsdale Quay), to minimize transfer times.
It sounds like it's well-suited to public transit in lower-density areas, like suburbs, where a bus might run every 30 minutes. A 1983 report from the US Department of Transportation includes a description of the timed transfer networks in Edmonton and in Vancouver. Timed Transfer: An Evaluation of its Structure, Performance, and Cost.
Jarrett Walker, a transit planner and the author of Human Transit, describes how this works:
A pulse is a regularly scheduled event, usually happening at the same time each hour, in which transit vehicles from a range of routes — usually running every 30 or 60 minutes — are scheduled to all meet together. A group of hourly local routes, for example, might all come to the pulse point between :22 and :25 after the hour and leave at :30. That way, nobody has to wait more than 8 minutes for a connection even though the services in question are hourly.
Pulses are the only way to provide connection wait times that are much, much better than the frequency of the services involved. A pure pulse is also equally convenient for connections between any pair of lines, and thus for travel in any direction.
For this reason they are used universally, in North America, in small-city networks where frequencies are low and often also in suburban areas of large cities. If you’re in a North American suburb or small city and see a large number of buses hanging out together on a street corner, you’re probably watching a pulse. The sight can be vaguely humanizing; for a moment it looks as though these big obtrusive vehicles are people too, with human needs for social interaction every hour or so.
Very cool. I admit, I have tried Vancouver buses and just despaired. The train is awesome, but the buses are just confusing and unreliable. I took buses in Spain 20 years ago now where every single bus shelter had an annunciator telling you how many minutes to the next bus arrival, for each route, like a train station. Those buses, I could use, though I did not speak Spanish. Ours, I get confused.