The Advantage of Connective Networks

It’s More than Buses was thrilled to host Darren Davis at the end of September. Darren is the principal public transit planner in Auckland, New Zealand. Under his direction, Auckland has completely redrawn their bus network. Early results are promising, with ridership up over 30% in some parts of the network. This type of radical re-design is both rare and incredibly inspiring. Auckland’s audacious transit plans hopefully represent emerging best practices for transit networks everywhere.

Darren’s expertise and direct experience with a complex transit network were a perfect fit for Halifax. Over the next few weeks we’ll look more closely at some of the lessons from Auckland that apply to Halifax. Today: connective networks.

Connections are critical. Darren’s motto (paraphrased) is that for a network to function,‘everything must connect to everything’. Good transit routes must connect together to serve many destinations.  Buses, ferries and trains must all connect to each other. If you care about the quality of service in your area, you have to care about the quality of service across the whole transit network.

Requiring (or providing, depending on viewpoint) riders to make a connection, to transfer between routes, sounds like an inconvenience. But a connective network can provide many times more service, to more destinations, at a similar cost, compared to networks that try to give everyone a route to everywhere.

Darren uses the diagrams below to show how a connective network works. Both diagrams are from Jarrett Walker’s blog Human Transit.



The first diagram shows a network that tries to give everyone a ‘single-seat ride’ to many destinations. There are many routes, but they don’t run very often. Every residential area has a bus going to each major activity area. This is very similar to how Halifax Transit’s network currently works, with the major activity areas being Downtown Halifax, hospitals and universities.

The bottom diagram shows a connective network, using the same amount of service. Every residential area has a high frequency route running to one activity area. To travel somewhere else, you’ll have to change bus routes (or streetcar routes, or subway lines, or rail lines. Regardless of the vehicles, the network principles apply). While this sounds like a huge pain, remember that we’re using three routes instead of nine. Having only a third the number of routes lets us triple the frequency in our connective network! So if buses in the single-seat network arrive every 30 minutes, in the connective network buses arrive every 10 minutes.

Frequent service is critical. It means you’ll spend less time waiting for the bus. In the single-seat network, people riding the bus wait on average fifteen minutes for a bus (average wait time is half of the 30 minute frequency). So even if you have a direct trip, you have long wait times on a single-seat network. In the connective network, people’s average wait time for a bus is five minutes (half of the 10 minute frequency). So for the one direct trip you can make (say taking the red line from Residential 1 to Activity Area 3 in the diagrams above), you’ve cut 10 minutes off the average trip, because the frequency is so much higher, and people spend less time waiting for the bus. For trips with a transfer (say Residential 1 to Activity Area 1), an average rider will spend five minutes waiting for the red line, and another five minutes waiting for the blue line when transferring. That’s 10 minutes of wait time in the connective network, versus 15 minutes of wait time in the single-seat network. Even though the distance people travel in the bus (or streetcar, or subway …) may be a bit longer in the connective network, the higher frequency in a connective network means less waiting. Less waiting time means that travel times in connective networks are comparable or better than single-seat networks. Connective networks offer access to many more destinations. Plus they offer much higher frequency, which is critical to making transit more appealing.

How else can we look at this? As both Darren Davis and Jarrett Walker note, connective networks offer many time more access than single seat networks: they provide more departures and access to more destinations! And they do that for the same price.

But, Halifax Transit isn’t building a connective network

Halifax Transit is undertaking a redesign of their network, called the Moving Forward Together Plan. This redesign started in 2013. The second draft of the Plan was approved in principal at the HRM Council meeting on April 12, 2016.

One principle of the Moving Forward Plan is to build a simplified, transfer based system (a connective network!). Unfortunately, Halifax Transit walked back that principle in an August 2014 report, when they reported to Council that a transfer-based (i.e. connective) network was not possible. Let’s just say we disagree. Completely.

The latest Moving Forward Draft is shown below. There are many routes heading to Downtown Halifax and universities: lots of core routes overlap in these same areas. This is certainly not a network that provides useful connections. It is a very complex network that poorly serves people travelling crosstown, and clogs up major streets with too many buses, each with too few riders. The network is too complex to properly map. Thin blue lines show over a half dozen routes on the same stretch of road, but its difficult to say where each route ends and begins.


The above map doesn’t even include all of the Halifax Transit routes! There are also rush-hour only routes, shown on the map below.


Notice how little area the rush hour buses cover. Going to the Dartmouth General? These routes aren’t. Halifas Shopping Centre and Mumford Terminal. Nope. But, all these routes overlap in a few places – the MacDonald Bridge, Gottingen, Barrington, Spring Garden and Morris. 19 separate routes rush hour routes go to Scotia Square, in addition to 10 all-day routes.

Our best guess is that in rush hour, there will be somewhere between 60 and 85 buses per hour stopping at Scotia Square. Between 120 and 170 buses every morning and afternoon rush! This is a bus sewer – a funnel of buses that provide little useful service but overwhelm a street. This is a problem that Downtown Halifax, Spring Garden Road and the North End business districts have been complaining about for years. The proposed Moving Forward Plan does not solve this problem. It doesn’t even take this problem seriously.

This is a major design flaw in the proposed Moving Forward network: a huge number of buses converging on one location. We already know what this looks like: buses running in clumps instead of providing useful frequency; the first two or three buses fairly full and the next four mostly empty (people understandably hop on the first express bus that they see at Bridge Terminal or Main Avenue); buses in line to get to a bus stop; and wall to wall noise and diesel fumes on Barrington Street; Spring Garden Road and Gottingen Street.

In a connective network, different routes are arranged to provide many travel options. In a single-seat network, routes inevitably overlap, wasting resources and providing no extra travel options.

Halifax Transit insists that the Moving Forward network provides the best of a single-seat network and a transfer based network. A close look at the horrendous overlap proposed for Downtown Halifax, and the terrible connections elsewhere in the region, suggest that Moving Forward is really the worst parts of a single-seat network, with hardly any of the immense benefits of a connective network.

This needs to change. Council must step up and demand a better solution from Halifax Transit. We’ll share our proposed changes to the Moving Forward Plan in the next post.



2 responses to “The Advantage of Connective Networks”

  1. […] is a dramatically better approach for Halifax then what Halifax Transit is proposing. It is a connective network, which provides many more travel opportunities for the same amount of […]

  2. […] bring in an international expert to review Moving Forward Together. We continue to advocate for a connective network, a more efficient design that would provide thousands of people riding the bus with faster travel […]

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