https://twitter.com/chittimarco/status/1699909618485416066?s=46&t=wToudP7CT55sD2jxPTMBpA
Reece @RM_Transit recently published a video about the “obsession” of some planners and advocates for tramways.
I tend to be mode-agnostic, but I share with Reece the idea that tramways have a very small niche to be effective in North America.
Let me explain you why. 
Let’s take a generic, sprawly and featur-less North-American metropolis. Maybe a Canadian-style one, with a dens-ish pre-war core, a vast sprawl of single family houses some 30+ km out of the core, a few clusters of suburban density but a clear built-unbuilt edge.
Our metropolis probably has a legacy metro network that serves its inner neighborhoods and a few suburban corridors but doesn’t reach the limits of the built-up area. It probably lacks a higher order rail-based mass regional transit, apart from a few peak-only commuter rail lines
Transit coverage of the outer suburban belt is the work of buses. If we take a quadrant, we will probably have a spaghetti of bus routes meandering around a group of neighborhoods and then expressing to a big bus-metro connection terminal or, during peak, directly downtown.
They are mostly routes with a base frequency of 30-60 minutes off-peak, maybe with higher frequencies on a few trunks. In some cities, like Toronto, the main arterials of that quadrant might even get all-day frequent service. But that’s the exception rather than the rule.
The average speed of these routes tends to be high for a bus, especially for routes with an express section, maybe on reserved highway shoulders or other priority measures. They are costly to operate outside of peak hours, but running times into the subway/downtown are good-ish
Can tramways be the solution to provide higher order transit service for that suburban quadrant?
I argue that: “tot really”, if we talk about “European-style” tramways with stops every 4-500m, limited grade-separation and thus a commercial speed of approx 16-22 km/h.
Why?
If we replace bus service along the trunk with a “European-style” tramway (blue), we will still need to rely on a network of feeding bus lines because, unlike, say, a suburban corridor of Paris’s banlieue, the walkshed of that line is not what builds ridership.
Most of the inhabitants of that suburban quadrant would need to take a bus to the tramway, than the tramway that feed into the subway and then the subway. What was a 1 (peak) or 2 (off-peak) seats ride becomes a slower 2 or 3 sets ride with additional waiting times.
Since the tram is only slightly faster than a local-express bus and definitely slower or as fast as an express bus, total travel times would probably even increase. Keeping parallel bus services, even at peak, would make the tramway unviable, adding unsustainable operating costs.
So, what is a better option to serve that suburban quadrant?
What many cities around the world have: an overlapping regional-level higher-order transit with stops some 2-3 km apart, grade-separated and an average speed of 50-ish km/h
Call it RER, S-Bahn, or ‘Daisy’, if you like
It’s important that this regional system OVERLAPS over the metro network, creating a second, preferably diametral, frequent & fast network multiplying the connecting points and not just feeding into the metro as a fast suburban feeder tail, as to avoid too many forced connections
The advantages of this type of service configuration for suburban trunks are :
- faster = lower operating costs
- faster trips to downtown, comparable to the pre-existing expresses
- better connections to the broader region (network effects)
The time and inconvenience added with a forced transfer is largely compensated by much faster travel times on a longer portion of the trip for most trips, better regional connectivity and more reliable travel times. Users trade one confortable trip with many more options
The argument that suburban tramways are better for local transit connectivity within the suburbs simply doesn’t hold in a NA reality were suburban local destinations are too sprawled. Density and land use is dramatically different compared to, say, around Paris’s T1
Tramways in large metropolises can work for:
- thickening inner-city coverage on high-ridership corridors (can happen in NA, see Toronto’s streetcars)
- radial/tangential suburban corridors with high density AND many connections to radial metro/RER (ie Paris’s suburbs but not NA)
What tramways aren’t good at in the sprawly, low-density and center-less NA suburbs is “lengthening the tails” of the trunk urban rail network, that is acting as intermediate feeder, to just serve the suburbs “cheaply” or in a more politically fancy way with rail transit
I think that, rather than building a tramway and short of investing on full-scale regional fast transit, it would be more useful and cost-effective for those suburban dwellers to implement diffused transit priority measures and build BRT-like infra on the trunk arterials.
As much as I love tramways like many people and I appreciate how they can be opportunities to deeply rethink urban spaces, transport-wise they occupy a defined niche: their sweet spot is medium density corridors and medium-sized compact cities. Not 1990s single-family suburbs.
).