The 1986 LRTA Study: Bus – LRT – Metro Comparison

Every year I reprint this post to remind everyone of the ability to move large amount of people at an affordable cost.

There is an ongoing debate today that LRT can only carry a limited number of riders and that the magic number for a subway is about 100,000 riders a day on a transit line. This may have been true in the 1970′s, but not the 21st century, where modern multi-articulated low-floor light rail vehicles (tram is much easier to say!) are able to easily carry three or four times this number, thus negating the need for expensive subway construction, except on the most heavily used routes. The LRTA shows that modern LRT can carry over 20,000 pphpd in 1986 and in 2010, in Karlsruhe Germany, one tram or LRT line on Kaisserstrasse was seeing traffic flows over 35,000 pphpd.

Karlsruhe also shows what the threshold for traffic flows necessitating  subway construction in Germany, after many very expensive lessons with subways built on lesser routes.

Those who demand a SkyTrain Broadway subway should take note.

The 1986 LRTA Study: Bus – LRT – Metro Comparison

 

A Vienna tram on a simple reserved rights-of-way.

The following is from the Light Rail Transit Associations hand book Light Rail Transit Today, comparing the operating parameters of bus, light rail, and metro on an unimpeded 8 kilometre route with stations every 450 metres. Using real data based on acceleration, deceleration, dwell time, etc., the study gives real time information for the three transit modes.

Please note: This study has been abridged for brevity and clarity.

The study assumes a vehicle capacity for a bus at 90 persons; LRT 240 persons (running in multiple unit doubles capacity); and metro at 1000 persons.

The time to over the 8 km. route would be:

  1. Bus – 22.4 minutes
  2. LRT – 18 .6 minutes
  3. Metro – 16.3 minutes

The Round trip time, including a 5 minute layover:

  1. Bus – 54.8 minutes
  2. LRT – 47.2 minutes
  3. Metro – 42.6 minutes

The comparative frequency of service in relation to passenger flows would be:

At 2,000 persons per hour per direction:

  1. Bus – 2.7 minute headways, with 22 trips.
  2. LRT – 7.5  minute headways, with 8 trips.
  3. LRT (2-car) – 15 minute headways, with 4 trips.
  4. Metro – 30 minute headways, with 2 trips.

At 6,000 pphpd:

  1. 1 Bus – 0.9 minute headways, with 67 trips.
  2. LRT – 2.4 minute headways, with 17 trips.
  3. LRT (2-car) – 4.8 minutes, with 13 trips.
  4. Metro – 10 minute headways with 6 trips.

At 10,000 pphpd:

  1. Bus – 30 second headways, with 111 trips (traffic flows above 10,000 pphpd impractical).
  2. LRT – 1.4 minute headways, with 42 trips.
  3. LRT (2 car) – 2.8 minute headways, 21 trips
  4. Metro – 6 minute headways, 10 trips.

At 20,000 pphpd:

  1. LRT – 0.7 minute headways, with 83 trips.
  2. LRT (2 car) – 1.4 minute headways, with 42 trips.
  3. Metro – 3 minute headways, with 20 trips.

Comparative Staff Requirements on vehicles in relation to passenger flows. Station staff in brackets ().

At 2,000 pphpd:

  1. Bus – 21 (0)
  2. LRT – 7 (0)
  3. LRT (2 car) – 4 (0)
  4. metro – 2 (up to 38)

At 6,000 pphpd:

  1. Bus – 61 (0)
  2. LRT – 20 (0)
  3. LRT (2 car) – 10 (0)
  4. Metro – 5 (up to 38)

At 10,000 pphpd:

  1. Bus – 110 (traffic flows above 10,000 pphpd impractical) (0).
  2. LRT – 34 (0)
  3. LRT (2 car) – 17 (0)
  4. Metro – 8 (up to 38)

At 20,000 pphpd:

  1. LRT – 69 (0)
  2. LRT (2 car) – 34 (0)
  3. Metro – 15 (up to 38)

Though the study is 30 years old and completed before the advent of low-floor trams (which decreased dwell times), it still give a good comparison of employee needs for each mode. Metro’s, especially automatic metro systems do require a much larger maintenance staff than for bus or LRT and when one factors in the added high cost of subway or viaduct construction plus higher operational costs, Metro only become a viable proposition when traffic flows exceed 16,000 pphpd to 20,000 pphpd on a transit route.

Claims from other blogs that automatic metros can operate more frequent headway’s than LRT are untrue; automatic metros can not operate at higher frequencies than LRT, but if Metro is operated at close headway’s in times of low traffic flows, they do so with a penalty in higher maintenance costs and operational costs.

Taking into account the almost universal use of low-floor trams, operating in reserved rights-of-ways, combined with advances in safe signal priority at intersections; given an identical transit route with equal stations or stops, LRT operating on the surface (on-street) would be just as fast as a metro operating either elevated or in a subway at a fraction of the overall cost grade separated R-o-W’s. Also, automatic (driverless) metros, though not having drivers have attendants and station staff, which negate any claim that automatic metros use less staff than light rail.

The LRTA study does give good evidence why LRT has made light-metros such a as SkyTrain and VAL obsolete.

http://www.railforthevalley.com/latest-news/zweisystem/the-1986-lrta-study-bus-lrt-metro-comparison/

Comments

2 Responses to “The 1986 LRTA Study: Bus – LRT – Metro Comparison”
  1. Haveacow says:

    The LRT number should be lowered to around 200 for crush capacity due to the fact that most North American designs are only 27-32 metres long per vehicle. Only Ottawa’s and Dallas’s electric LRV’s are longer at 48 and 37 metres respectively.

    Most diesel LRT services use mainline compatible railway Diesel Multiple Units (DMU’s) instead of truly diesel LRV’s. Most of these DMU’s range between a length of 36-48 metres per vehicle.
    .
    You should update the bus category to cover the fact that most 12 metre or 40′ bus models couldn’t hold above 65-70 passengers at crush capacity and realistically speaking, most models because of low floor designs and wheelchair access can’t handle more than 55 at crush capacity.

    Most 18 metre or 60′ single articulated bus models claim around 105-110 at crush capacity but rarely break 100 in reality. In fact, 90-95 would be more accurate.

    Lower all estimates by 5-10% in winter due to the heavy bulky clothing warn by most Canadians outside of Vancouver (first heavy snowfall of this season today here in Ottawa, arrgh!).

    Bi-articulated bus designs (it is a design because they are rarely used) will hold approximately up to 140-150 at crush however, if it is a low floor model lower that total to around 125-130.

    Most designs of tri-articulated bus designs claim 180+ but usually 175 passengers at crush capacity is most likely. If it is a low floor design drop it to 150-160.

  2. zweisystem says:

    Just a general note. TransLink and its surrogates have claimed in the past that crush capacity on MK.1 cars is a 100 people and 150 on MK 2′s, yet correspondence from yourself and from other transit professionals has put this number much lower. Taken a step further, this means that Translink’s hourly capacity is much lower than claimed.

    What is of more interest, with the compass Card, TransLink could reveal daily the actual number of people using the system, by one tap in, yet TransLink still uses boarded numbers which with the fragmented transit system, on boarded customer could equal up to 8 or more boardings!

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