Some challenges for a Broadway LRT

April 21, 2011

Friday is the last day to provide input to the phase 2 of UBC Rapid transit study. Below, we consider some challenges associated with a surface solution, noticeably LRT on Broadway

Safety question

The suggested average speed, in the vicinity of 30km/h, can be considered relatively high: It is the speed achieved by the 99B when traffic is light. Thought such speed is very achievable by LRT, example of LRT running at such average speed in area presenting similarity with Broadway hasn’t been provided.

We could think of the blue line in Los Angeles, one of the busiest in North America, with over 80,000 boarding/day. The inconvenience of this example, is that with over 100 people killed on the track of this LRT line since its inspection in 1990, it is also one of the most treacherous LRT line in North America.

Unfortunately, like I have previously noticed, accident rate and ridership can be pretty well correlated. European tram achieve good safety record by running simply at much lower speed than their american counterpart in urban environment comparable to Broadway.

Confidence in travel time

  • Is the modelling for surface transit assuming a perfect world?

On this topic, one will notice that, not unlike other French tram project, the Paris tram T3 average speed had been over estimated by more than 25% during the public consultation. the given reason is that the world was less perfect that expected, since you will find jay walker undisciplined car driver and other behavior affecting the average speed [6]

Capacity

An LRT line can move huge number of people, and Translink advance number as high as 10,000 person per hour per direction, but what is the price to pay for it?

there is a limit on frequency possible while still having traffic signal preemption. this limit imposes either capacity or speed/frequency reliability. credit (3)

At some frequency point, traffic signal priority can’t get granted. That is the reason why Translink provide slower travel time with a BRT (which need to be more frequent) than a LRT.

  • what is the highest frequency achievable with the posted travel time. or
  • what is the maximum capacity for the system without compromising travel time?

As a matter of reference, In European literature, we will find a capacity limit of a tram at around 6,000 persons per hour per direction, in normal condition (headway enabling traffic signal preemption) [5].

Platform width

narrow platforms could be quickly overcrowded thanks to high ridership. credit photo (1)


Again, comparing with the Paris T3 trams with a ridership of 110,000 people, similar to the one envisioned for Broadway…In the Parisian T3 case, the boarding is done at 17 stations with platform of 5 meters width..when the Translink study suggests boarding at as little as 13 stations of around 3 meters width…In Edmonton, the LRT has central platform width of 8 meters.

  • That is, the suggested boarding area proposed by Translink could be more than twice smaller the one offered by the Paris tramway T3.

Paris tram t3 side platform (right) are 5 meters wide, and Edmonton central platform (left) are 8meters wide...does 3 meters platform wide will be enough to handle expected ridership on Broadway? credit photo right (2), left (3)

  • How platform crowding gonna impact the dwelling time? Waiting experience?

Interference with local bus routes

It has been admitted by the Translink planners that a surface LRT will impact negatively local route along Broadway, what is not hard to fathom…
According to the frequency of the surface LRT it will also impact the travel time of crossing route due to signal preemption by the surface LRT. The measured impact of it has not been provided.

street-scape

The 99feet wide Broadway is mostly dedicated to vehicular traffic. Does the streetscape could provide more space to pedestrians and be more cyclists friendly? credit photo (8)

Broadway is not that wide, and implementation of an LRT supposes some compromising. Note surprisingly, parking lanes could disappear, but may be more of a concern could be the reduction of pedestrian space on sidewalk required at station location. Platform wide inline with the one seen on system with comparable ridership, suggest that an broadway LRT could reclaim 11 to 12 meters ROW, at station location, that is close to the equivalent of 4 lanes of traffic to remove. Cyclist are not expected to be on Broadway, and anyway current preservation of sidewalk width could prevent bike parking.

  • An LRT is often considered as an opportunity to improve the street-scape but it also imposes constraints

Since Allan Jacobs is scheduled to be a keynote speaker at an upcoming SFU conference on the future of Broadway, it could be interesting to compare Broadway to Boulevard Saint Michel in Paris. the later Boulevard is 30m wide, so similar to Broadway, but with a significantly different space allocation since it has only 4 lanes of traffic making room for ample sidewalks allowing coffee patios…Boulevard Saint Michel is what Allan jacobs consider a Great Streets.

  • Does the need to accommodate an LRT will not compromise a similar fate for Broadway?

Ample sidewalks allow for life and social interaction on the 30meters wide Boulevard Saint Michel in Paris. Large sidewalks grant airspace for majestic trees. This Boulevard is considered a 'great street'by Allan Jacobs. credit photo left (7)

But more important, as noticed by Allan Jacobs, with the Champs-Élysées Avenue, and as we know it here with Granville Street, a street could needs several iterations of work before becoming a “great street”.

  • Does the permanence of an LRT will not compromise the ability to correct unavoidable mistake, or rather to allow the streetscape to evolve in function of new and unforeseen future needs?


[1] Keegan Bursaw

[2] Живые улицы

[3] one42chrisp

[4] Simon Chambers

[5] BHLS or tramway in France : scope of application and choice, Sébastien RABUEL, CERTU, French Ministry of Transportation, July 13th – 2010

[6] A french audit has mesured the average speed of the Parisian tramway t3 at 16 km/h instead of the the planned 20km, ibid. “Le tram se traîne“, Dec 23, 2009, Le Parisien

[7] Adrian

[8] Boris

[8] Great Streets, Allan jacobs, MIT Press, 1995

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