The 1986 LRTA Study: Bus ai??i?? LRT ai??i?? Metro Comparison

I thought I would again reprint this post from May 20, 2010 as it may clear up some major misconceptions about LRT capacity, since many in Metro Vancouver are very confused about modern light rail.

There is an ongoing debate today that LRTAi??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 1970ai???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 is for subway construction in Germany, after many very expensive lessons with subways built on lesser routes.

The 1986 LRTA Study: Bus ai??i?? LRT ai??i?? Metro Comparison

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 ai??i?? 22.4 minutes
2. LRT ai??i?? 18 .6 minutes
3. Metro ai??i?? 16.3 minutes

The Round trip time, including a 5 minute layover:

1. Bus ai??i?? 54.8 minutes
2. LRT ai??i?? 47.2 minutes
3. Metro ai??i?? 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 ai??i?? 2.7 minute headways, with 22 trips.
2. LRT ai??i?? 7.5Ai?? minute headways, with 8 trips.
3. LRT (2-car) ai??i?? 15 minute headways, with 4 trips.
4. Metro ai??i?? 30 minute headways, with 2 trips.

At 6,000 pphpd:

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

At 10,000 pphpd:

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

At 20,000 pphpd:

1. LRT ai??i?? 0.7 minute headways, with 83 trips.
2. LRT (2 car) ai??i?? 1.4 minute headways, with 42 trips.
3. Metro ai??i?? 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 ai??i?? 21 (0)
2. LRT ai??i?? 7 (0)
3. LRT (2 car) ai??i?? 4 (0)
4. metro ai??i?? 2 (up to 38)

At 6,000 pphpd:

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

At 10,000 pphpd:

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

At 20,000 pphpd:

1. LRT ai??i?? 69 (0)
2. LRT (2 car) ai??i?? 34 (0)
3. Metro ai??i?? 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. Metroai??i??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-Wai??i??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/