A lot of the transit plans have focused on rapid transit on more of a regional level (and rightly so). But I've started to think about how to deal with the smaller, inner-city trips.
Background, this is the post which I made a few weeks ago which has had me toying with the idea:
Quote:
Regarding the "surface vs grade-separated" debate, I've been thinking about this in the context of Ottawa's urban main streets. The way I see it, there are benefits to both approaches:
- Grade-separated (GS)
Pro: Faster vehicle speeds (because fewer stations, exclusive ROW)
Con: Longer walk to station (because of fewer stations), longer pedestrian access times to platforms (because not at street level)
- At-grade (G)
Pro: Shorter pedestrian access times (because at street level and more stations)
Con: Slower vehicle speeds (because more stations, non-exclusive ROW)
This means that GS systems are more useful when you're going long distances because you spend a greater percentage of your time in the transit vehicle as opposed to walking there. For example, you have to go 20km and you either have a 20km/h tram 5 minutes from your door/your destination or a 40km/h subway 10 minutes from your origin/destination. The added 10 minutes of walking is more than offset by the 30 minute reduction of in-vehicle time.
G systems are better for short distances because a bigger share of your time is likely to be spent walking to and from stations. In the same situation, travelling 2 km by subway would total 26 minutes but the tram would get you there in only 16 minutes.
I'm assuming that surface LRT (like Edmonton's Valley Line) runs about 20km/h with stop placement every 500m and that a subway/skytrain runs at 40km/h with a stop every 1000m and require 1.5 minutes to get from the station entrance to the platform (ascending 15m by escalator is about 40 seconds, plus walking on the concourse). I'm also assuming the average walk applies on both ends of the transit trip. With these parameters, surface transit is faster for trips under 8.5km, and GS systems faster above that.
For those interested, here's my formula: (X km/20kph*60min)+10min walk=(X km/40kph*60min)+20min walk+3min access, where X is the point at which GS is faster than G.
There are a few interesting implications as well as some limitations to this model.
For implications, this is an indication that for urban transit corridors where people will generally be walking/cycling to stations, a subway might actually result in longer trips than a surface alternative. I'll soon experience this phenomenon; Currently, I'll often take Ottawa's Transitway BRT for 1-2 stops downtown just because I can easily hop onto a bus from the curb (and because I'm lazy). Once LRT opens, the trains will be faster, but once I factor in the time it takes to get down to the platform and back up again, it'll likely be faster for me to walk those same distances.
So for urban corridors, good surface transit will result in the fastest trips even if the vehicles are slower. Ottawa's Bank/Rideau, Montreal's St-Laurent, and Toronto's King are good examples of this; most people on this corridor walk from their house to the street and have their destination within walking distance too.
However, there are limitations. If this is a transit line which mostly relies on transfers as opposed to walk-in traffic, the difference is largely evened out since there's no difference in access time to the line on one end of the trip. In that case, surface transit is only faster for trips under 5km (excluding the time on the transit line to/from which passengers transfer). The YUS Line is an example of this; although it has walk-ons, I believe that most of the passengers transfer onto the line and then walk to their downtown destination.
And of course, if most passengers transfer on both ends of their trip on a line, GS is always faster. Montreal's Yellow Line is an example of this; the lion's share of passengers transfer by bus on one end and transfer to the metro on the other.
So to sum it up, surface transit is faster under:
Walk-transit-walk: <8.5km
Transit-transit-walk: <5km
Transit-transit-transit: [GS always faster]
So instead of debating which one is always better in all cases, I think that it's important to look at the context and to choose the best mode accordingly. In certain contexts, a faster vehicle may end up in higher trip times for most passengers. And in others, surface options, although they may be attractive from an urban design standpoint, they might not actually be the best option in terms of getting people where they need to go.
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So for Ottawa, I think that we could best serve the inner-city trips with improved surface transit. I've come up with a rough-and-dirty map which shows how I imagine this working:
In red, we have our metro lines, including eventual Gatineau lines over the Alexandra Bridge. These are frequent lines which are mostly aimed at longer distance trips (>5km).
In yellow, we have surface transit. These are frequent trunk lines which are intended for trips under 5km (Say, Lansdowne to Chinatown, Vanier to Downtown, etc.). They'd likely be bus-based to start, but if ridership on one line or another becomes too high to service with buses, it could accommodate both bus and surface LRT/streetcar. This trunk can also accommodate other regular bus lines (like those from Somerset, Elgin, Beechwood, etc.).
In darker yellow, we have dedicated transit lanes (on the Portage Bridge) and transit only streets:
- Queen Street: With some short exceptions for parking access (like 240 Sparks), traffic is restricted to transit and delivery vehicles
- Rideau Street to Dalhousie: Similarly to today, only transit vehicles can use it. This opens a lot of space for pedestrian circulation, and for patios and store displays to spill into the street.
- Bank St north of Laurier
- Bay St north of Queen, allowing for STO buses to get to and from the Portage Bridge.
In lighter yellow, we have transit-priority streets. These are streets which limit car through-traffic with a combination of either peak hour or permanent turn restrictions, forced turns, and deviations. For example, the Cummings Bridge might be made transit-only at peak hours, which keeps Montreal Rd and Rideau from getting clogged with vehicles headed east from Downtown. This ensures greater speed and reliability for transit vehicles as well as local access.
- Bank St north of Billings. South of Billings, the street is wide enough for dedicated transit lanes and car lanes.
- Rideau/Montreal west of St-Laurent.
The result would be an intermediate step between metro and local bus which manges to serve Ottawa's urban neighbourhoods. As many people have pointed out, the Confederation Line isn't particularly useful for a great number of urban trips. Worse still, with the system redesign, many people might be forced to make a transfer from their bus to LRT for one station before transferring to yet another bus. A downtown surface transit trunk would allow for better local service, avoid unnecessary LRT transfers, and has the potential to relieve parts of the Confederation Line.
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A special note on the whole Rideau/Elgin/Sussex mess. I quickly drew up an idea of what this could look like to accommodate a transit corridor. In red, I have the transit trunk.
- All car traffic would be placed west of the War Memorial
- The transit lanes would run to the east of the Memorial with a station on the Plaza Bridge (which I called Canal), right above the Gatineau LRT terminus.
- A simplified Mackenzie/Sussex/Rideau intersection would allow for the elimination of the horrible pedestrian underpass, replacing it with a building to reduce the gap between the Market/Rideau/Lowertown and Downtown.
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