November 3, 2014
Some numbers extracted from the Translink GTFS feed  (for the day of Sept 5th, 2014), for the 2km segment between Hasting and Broadway. The current average speed is ~11.5km/h, could be increased to ~15km/h with a bus lane…or reduced to ~9km/h according to the tradeoff done to implement bike paths
- number of #20 runs: 304 (but I counted only 276 between Broadway and Hasting) requiring a minimum of 19 vehicles in revenue service 
- time and speed between Broadway and Hasting :
- ~15,700 annual operating hours meaning $1.57 millions in annual operating cost (at $100/hr, in line with )
|Min time||Average time||Max time|
|Max speed||Average speed||Min speed|
bus lane Impact on Commercial Drive
We are considering the previously presented Commercial Drive proposal as illustrated below
- This bus lane, featuring clearly marked corridors (protected in one direction) and transit priority signal, suggests that average speed typical of BRT or urban LRT could be achieved: that is ~20km/h.
- That said, noticeabily because the stop are closely spaced, an average speed of 15km/h could be more realisticaly and conservatively achieved:
- That is roughly the average speed of the bus 20 outside the Commercial Drive segment.
Annual operating cost
|average speed||Average time||Annual operating cost|
The potential operating cost saving is in the tune of of $300,000 to $600,000/year.
Similar configurations, be on Davie or Robson, suggest a reduction of the average speed to ~9km/h; That could increase the route 20 operating cost by $400,000/year:
- the bus+bike lanes proposal is conductive of $1 Million in operating cost saving versus a proposal favoring street parking over transit.
A bus lane + traffic signal priority, allows an increase in the bus schedule reliability: lay over can be reduced accordingly, increasing the operating saving
Operating cost is only part of the picture:
the slower a bus route is, the more buses are required at same frequency/seat capacity:
The bus requirement is compounded by two conflating issues:
On the route 20, afternoon peak hour traffic cost ~4 buses:
A bus lane, making transit more immune to traffic congestion, allows to reduce drastically the peak hour buses requirement (in our example, the average speed maintained at ~15km/h, vs 9.5km/h currently in peak hour)
Adding a peak hour bus is a very expensive proposition: it means (to preserve spare ratio, and other contingency)
- the Purchase of an additional bus
- Adding storage capacity for this bus (even if in use 20mn a day)
- Adding maintenance cost
- adding a driver on payroll and all ancilliairy cost (training, administration)
According to a conversation with a former Toronto Transit Commission employee, the TTC is costing an additional peak hour bus at $100,000 a year (that is for a 40footer, typically sold a ~$300,000)
It is worth to note that Translink is in very short supply of articulated trolleybus, estimated each at $1M
It is no secret that the faster a transit service is, the more ridership it will attract. That has been again recently verified in Seattle, with a quasi linear relationship:
- an increase of 20% in speed is conductive of a similar increase in the ridership, which de facto increase the bus operator revenue
This coumpounded to lower operating cost makes Transit much more financially sustainable.
When all the effects are combined, it is relatively conservative to estimate that a bike lane, done at the expense of transit on Commerical, could end up to cost more than $1 million/year to Translink, when compared to a solution improving both
…and here we have analyzed only the direct cost for Translink…
 New markings aim to keep drivers out of Battery Street bus lane, Aubrey Cohen, SeattlePi- Tuesday, October 21, 2014.
 That makes the route 20 the 4th most frequent bus route of the network, behind route 99,9 and 41.
 See our reference spreadsheet (which has been updated with the 2014 data) for further detail.
 We use here the hourly operating cost as stated in the 2013 Bus Service Performance Review (see Annex A): it is worth to note that this hourly operating cost doesn’t include neither bus lay over and dead end trips. It doesn’t differentiate artics buses from standard ones too: the $100 mark is a very significant under estimate of the real operating cost of a route. A $180 per customer hour service could be closer to reality as we have seen before.
 It seems that the average speed of the route 20 is decreasing year over year, almost 10% reduction in the last 7 years according to our spreadsheet  (which also depends of the Translink data quality): A probable consequence of the city council inaction on Transit front
October 25, 2014
September 22, 2014
The first round of segregated bike tracks has essentially concerned non essential transit corridors (Dunsmuir, Hornby…), but it is natural for cyclists to expect similar bike facilities on the Main arterial of the city, where shopping destination are located. Not surprisingly some groups are making pressure toward it. That should be an opportunity for the various municipal candidates to offer their vision and their differentiators on a complex problem which will require significant trade-off, and priority setting. Since transit has been much neglicted by the current council, the prospect of bike lane along transit corridors become a matter of concerns for Transit advocates
Below is an exert of the “Commercial Drive Campaign” by “Streets for Everyone” :
The main strength of this proposal is that it exists and provides a basis for discusssion. It also highlight the reason of our concerns in regard of Vancouver bike lanes: They obey to a disturbing sense of priorities:
- “Our plan leaves parking intact on both sides of the street”
…The same sense of priorities which could have lead to pave Kitsilano park to save street parking. Here there is no park, but there is the very important transit route 20, which is neglicted: It is nevertheless called a “win-win-win” proposal by some bike lanes advocates for the reasons below:
|Pedestrians||Cyclists||Transit Users||Car Users||Emergency Vehicles|
This layout, where the bus can be hold back by left and right turning cars, as well as the occasional parking car, is obviously very detrimental to Transit:
- On could expect the average speed of the bus 20, actually ~ 14km/h, to slow down to the one of the bus 5 or 6 (lower than 9km/h), which face similar street configuration (single traffic lane + parking lane). Speed is an issue, reliability is another one.
Such a slow down can have a dramatic impact
- On the attractivity of Transit, defeating a purpose of a street calming effort (get more people to choose alternative mode to car)
- On the operating cost of the line. so such proposal can be in be fact very costly .
It is hence very important to find a compromise which not only is not detrimental to Transit but can also be an opportunity to improve it:
Thought Commercial Drive is relatively narrow (80feet), it is possible to find an arrangement which improve the bike experience as well as the Transit experience:
The width of the all purpose lanes is what can be seen on most of the Vancouver residential street, such as 6th avenue (#Commerical),
- It is enough to preserve a parking lane, but that means drivers must be willing to “share the street” and negociate with other drivers, as illustrated in the above rendering, on some uncommon but possible traffic case involing large vehicles
- Traffic lane are ~3m wide, not unlike the traffic lanes on Number 3 road in Richmond (North of Westminster Hwy)
- The bus lane on the parking lane side is “protected”, both from dooring and ill parked vehicles, while the one on the other side can be infringed (“mountable obstacle”) to allow occasional passing of large vehicle
- The Bus+bike lanes are 4.5meter wide, a parisian standard . Could it be possible to slighlty separate them, in a Dutch way (that is by having raised bike lane)? may be, but the preservation of a parking lane make the proposal difficult.
- The bus lanes morph in emergency lane when needed
- Narrow traffic lanes are a powerful device toward traffic calming
All in all:
|Pedestrians||Cyclists||Transit Users||Car Users||Emergency Vehicles|
The above is a suggestion fitting better the objective of the 2040 Vancouver transportation plan: It must certainly exist better layouts. A complete economic analysis of a street layout could be useful to determine the objective value of one layout vs another one .
This proposal, as the “Streett for everyone” one, is uncompatible with the Mayors council idea of a hierarchized (local+express) transit service on Commercial, idea proposed for the Transit referendum
“Street for every one” suggests “dutch intersections” pretty much every where:
We prefer a more traditional bike box (doubled of a “queue jumper”) on street bereft of bike lanes: A solution avoiding some unnecessary conflict, and also more friendly to pedestrians (no detour imposed around the dutch “circle”):
 Here, we mention only the Transit operating cost, which could increase in the tune of million of $ due to lack of bus priority, but Transit lack of efficiency has more generalized social cost, in term of lost time,… as suggested by George Poulos on Price Tags
 The blue car in the rendering is a Toyota Passo, it is a sub compact car, not seen in North America. We have included the same car in our rendering along other more common model seen in the Vancouver street to provide a better idea of the width of the different lanes.
 The STM is also experimenting a 4.5 meter wide bus+bike lane on Viau Street in Montreal, albeit with slightly different configuration (see “Can buses and bikes safely use the same reserved lane?, Montreal Gazette, July 14, 2014 )/p
September 5, 2014
Below we provide mainly some number coming from , using a data base; the “registre du Rhone” (Lyon district, France); recording detailed information for 14 478 cyclist victims of road accident in the Rhone county (France). The data under studies have been collected from 1996 to 2007. The level of detail is very high compared to some other data base, and they can help to clarify the helmet debate:
see wikipedia for the AIS and IIS definition and meaning
Injured Body part among cyclists
reported numbers are only for cyclist where the helmeted/unhelmeted status is known
|helmeted 1461||unhelmeted 5620||helmeted 1461||unhelmeted 5620|
This table shows that the helmeted cyclist are less often severely injured to the head, less often injured and seevrely injured to the face. But they are more often injured and severely injured to the Thorax and spine, and more often injured to the upper extremity. This suggesthelemeted cyclist get involved in more severe accident. 2 reasons can be advanced for it
- Helmeted cyclists have a different cyclist practice that non helmeted one (that relate to the infamous MAMIL)
- There is a risk compensation at play along helmeted cyclist
the effect of it is to give an over estimate of the helmet efficiency
The figure below illustrates the % of head injuries oberved for injuried cyclists with an helmet and without:
So we are looking at a global effect of 1%, but severe head injuries can have long term disabilities consequence, so a reduction by 50% of severe head injuries could be considered a worth endeavour:
Below a more detailled view of the head and face injuries specificities:
Head or face Injuried cyclist: type of lesion according to helmet wearing or not
|Helmeted 238||Unhelmeted 1078|
|Unconsciousness without additional descripted lesion or head trauma without further indication||194||73,5%||668||49,3%|
|Destruction skull and brain||0||-||2||0,1%|
In despite of a pretty huge database, significativity is not reached on many lesions types.
According to , Among the 222 cyclists injuried to the skull or its content
- 30 are dead
- 42 will have severe heavy brain disabilities (IIS3) – that represents 0.3% of the injuried cyclist
- 146 will have light brain disabilities – that represents 1% of the injuired cyclist
The effect of the helmet on long term disabilities seems to be measured on a very small cohort:
|unhelmeted 35||helmeted 3|
|%fatalities among total injuried||0,3%||-|
|%fatalities among head injuries||1,4%||-|
|Severe head disabilities (IIS3+)||20||3|
|% Severe disabilities among total injuried||0,4%||0,2%|
|% Severe disabilities among head injuried||1,9%||1,3%|
|% Other severe disabilities in addition of severe head disabilities ||19,8%||21,4%|
Again, we don’t reach significativity to be able to conclude that a “bike helmet saves life”, but it could well reduce significantly the risk of severe head disabilities. The number could suggests 50%, but again with very little confidence.
In anycase, the effect is measured in tenth of 1% of the total injuries: the absolute number of victim is very small.
How bike injuries compare to other transportation mode?
When involved in an accident, cyclists have the lowest fatailities rate compared to other individual transportation mode. They have also the best chance to survive an accident without long term disabilities. Urban cyclists are even much safer than rural or suburban cyclists:
|Injury severities||Uurban 6584||Rural 1726||0-10years 3364||Pedestrians 10131||car 53151||Mopette Motorbike 21831|
|MAIS 4 and 5||0,9%||2,0%||0,3%||2,3%||1,0%||1,5%|
|light diabilities (MIIS1-2)||20,2%||23,8%||11,1%||29,6%||42,8%||23,8%|
|severe disabilities (MIIS3-6)||0,6%||1,2%||0,2%||1,6%||0,7%||1,3%|
When urban cycling is considered alone, helmeted cyclists are observed to have 20% less chance to be severly injured that non helmeted one, whenever involved in an accident, however significativity is not reached .
The figures below eventually help to compare the different pattern of injuries, according to transportation mode, and eventually relativize the impact of a bike helmet on the total number of both severe head injuries and severe disabilities.
those figures provide absolute numbers for the Rhone district (1.7Millions) inhabitant for years 2007-2010…
Even if a bike helmet is able to reduce the severe head injuries and disabilities, by 50%, the saving in term of public health could be relatively insignificant but the more generalized economic cost can be real: It has became clear that an helmet legislation is counterproductive, but even promotion campaigns in favor of bike helmet could be counter productive:
- The money spend on helemet couldn’t justify the health care saving, and could be better invested somewhere else
- Helmet campaign promotions paint cycling as a dangerous transportation, discouraging people to cycle, conducting to a less healthy population
One could object that a low absolute bike injuries number is due to a relatively low cycle ridership. The dramatic increase in cycle ridership over the last decade, especially in urban area, is well documented, and still the number of total injuries has not increased but is decreasing :
The more people bike, the more a bike helmet becomes irrelevant…unless you believe pedestrians should wear an helmet too!
More citation to come
 Vélo et casque, Journée spécialisée, jeudi 28 mai 2009, Rapport UMRESTTE 0908, May 2009
 doesn’t express it like it, but I am assuming it is due to a typo.
September 3, 2014
The strong bike helmet lobbying push seems to have started with a widely quoted 1989 paper from Thomson & Rivara,  that makes the bold claim that:
“we found that riders with helmets had an 85 percent reduction in their risk of head injury … and an 88 percent reduction in their risk of brain injury”
That finding has been a foundation for helmet legislation calls. Alas, after legislations were passed, be in Australia or in BC, leading to a significant increase in helmet wearing , numbers suggested by  never materialized . Worse, the bike helmet legislation seems to have no impact on bicycling safety , the later study justifying a British Medical Journal editorial advising against helmet legislation .
It quickly appeared that  had many flaws as debunked in , and effectively recognized in a BMJ editorial  …That has not prevented an author of , Rivara, to publish many more papers always claiming impressive efficiency for bike helmet, but always presenting similar flaws as identified in  (confounding factors) . A meta study published in 2001, , was also associating bike helmet with an impressive 64% reduction of risk of head injury and  confirmed those results and reported even more impressive reductions in the risk of head injury. Alas the studies included in both  and  have been demonstrated to be the result of a severe selection bias. After correction of this selection bias,  found that a bike helmet was reducing the risk of head injury by ~15%. The US National Highway Traffic Safety Administration (NHTSA) dropped claim that bike helmets reduce head injury by 85% as this number has no credible basis.
While initial claims on the head injury risk reduction offered by bike helmet has been proven unfounded, and bike helmet legislation shown ineffective at increasing bike safety, it appears that such legislation could discourage cycling , what is eventually conductive to lower bike safety and less physical active population with detrimental effect on the population health . Overall, a bike helmet legislation can quickly be considered as having a negative impact on public health . Wherever more general economic impact is considered, the picture can become even bleaker .
In despite of the above, the bike helmet controversy has side tracked the research community…which focuses more on the way to mitigate the consequence of bike accidents rather than addressing their causes. As an example, several studies have reported an alarming rate of alcohol intoxication among injured and deceased cyclists, but the helmet lobby has totally seized the debate to a ridiculous point:  observing that half of the cyclists who died in Oregon, were alcohol intoxicated, has -in fine- no better recommendation than promoting bike helmet…among drunk cyclists!
It also take considerable energy by cycling promoters to counter misleading claims advanced regularly by the bike helmet lobby. A recent example below:
Following the publication of , The University of Washington and Washington State University, issued a press release titled “Study correlates presence of bike-share programs with more head injuries” stating :
“Risk of head injury among cyclists increased 14 percent after implementation of bike-share programs in several major cities ”.
The journalists, who are not epidemiologists can’t be reasonably blamed to reporting what is told to them by some unscrupulous researchers, considering that the study has been published, after a peer review (How to argue against that?). However in despite of evidence of misrepresentation of facts reported in various social media, they didn’t issued appropriate correction to their original story (and have preferred to close the comment section) and that is a fault.
The unscrupulous researchers can certainly be blamed for their absence of ethic:
We will pass on the unprofessional self promotion of the previous authors’ publications, such as the now well discredited , this, in no uncertain term:
“Solid data from well-designed studies support the effectiveness of bicycle helmets and legislation mandating their use”
As we have seen, that can’t be farther from the true, but the real problem is the thrust of the article and a misplaced conclusion, as well exposed by 
However, the bulk of the blame should go to the American Journal of Public Health editor; Dr. Mary Northridge; to have accepted to publish what appears to be a scientific fraud. Such an article should have never been accepted under such a form and it has clearly not been properly peer reviewed:
Peer reviewing to work, suppose trust in the ethic of the authors (no intention to deceipt…), however, just the name of the authors should have already been sufficient to raise an eyebrow: Frederick P. Rivara, not stranger to deeply flawed studies and scientific controversy, is considered by many as nothing more than a charlatan; noticeably for reason exposed above; and considering this infamous record, the minimum of precaution could have been to choose at least some reviewers showing more scrutinity ability than complacency.
The minimum the American Journal of Public Health can do is to issue a correction, clearly stating the observed reduction in head injury in cities having a public bike share program as pointed by K. Teschke , this in a proeminent place and endorsed by its editorial board
In the meantimes, this episode will have helped to make clear how deep is the lack of ethic among the bike helmet supporters, to the point to even embarrasse some of them . It will help to convince more people to be not only very critical of the bike helmet lobby claims, but also aware that a peer review process is unfortunatly not synonym of quality.
 “A case control study of the effectiveness of bicycle safety helmets “, Thompson RS, Rivara FP, Thompson DC , New England Journal of Medicine v320 n21 p1361-7; 1989
 “Effectiveness of bicycle safety helmets in preventing head injuries: a case-control study “ . Thompson DC, Rivara FP, Thompson RS., JAMA 1996 Dec 25;276(24)
 Helmets for preventing head and facial injuries in bicyclists. Cochrane Review. Thompson, D.C., Rivara, F., Thompson, R., 2009. The Cochrane Library (1), 2009
 Bicycle helmet efficacy: a metaanalysis. Attewell, R.G., Glase, K., McFadden, M., Accident Analysis and Prevention 33, 345–352, 2001.
 Publication bias and time-trend bias in meta-analysis of bicycle helmet efficacy: A re-analysis of Attewell, Glase and McFadden, 2001. Accident Analysis and Prevention 43 1245–1251, 2011
 Head injuries and bicycle helmet laws, Robinson DL, Accid Anal Prev. 1996 Jul;28(4):463-75.
 “Bicycle-related head injury rate in Canada over the past 10 years” ,Middaugh-Bonney, T.; Pike, I.; Brussoni, M.; Piedt, S.; MacPherson, A. ; Injury Prevention 16: A228 2010
 Helmet legislation and admissions to hospital for cycling related head injuries in Canadian provinces and territories: interrupted time series analysis.Dennis J, Ramsay T, Turgeon AF, Zarychanski R. BMJ 2013
 Bicycle helmets and the law, Wellcome G. And Spiegelhalter Winton D., BMJ 2013
 misguided doctors or marketing agents? June 11th, 2012, Cyclists Rights Action Group
 The Health Impact of Mandatory Bicycle Helmet Laws, de Jong P. ,Risk Analysis, Vol. 32, No. 5, 2012
 New Zealand bicycle helmet law—do the costs outweigh
the benefits? Taylor M. And Scuffham P. Injury Prevention 2002;8:317–320
 Bikes, Helmets, and Public Health: Decision-Making When Goods Collide. Bateman-House A. ; American Journal of Public Health ; Vol 104, No. 6, June 2014
 Injuries Resulting from Bicycle Collisions Frank E, Frankel P, Mullins RJ, Taylor N. Academic Emergency Medicine, Volume 2, Issue 3, pages 200–203, March 1995
 Few study exist – except maybe  suggesting that the social cost of outfitting every cyclist with an helmet was not economically justified – But as far as we know, there is no comprehensive study examining the implication of transportation mode substitution, under a transportation economic perspective (time saved or not, infrastructure cost…)
 Bicycle helmet use in British Columbia, Foss RD, Beirness DJ, UNC Highway Safety Research Center; Traffic Injury Research Foundation, as cited by cyclehelmet.org
 Bicycle helmet legislation: Can we reach a consensus?, Robinson DL, Accid Anal Prev. 2Volume 39, Issue 1, January 2007, Pages 86–93.
 Public Bicycle Share Programs and Head Injuries; Janessa M. Graves, Barry Pless, Lynne Moore, Avery B. Nathens, Garth Hunte, and Frederick P. Rivara.; American Journal of Public Health: August 2014, Vol. 104, No. 8, pp. e106-e111
 “Study correlates presence of bike-share programs with more head injuries” College of Nursing; Washington State University, June 9, 2014
 “As if we needed another example of lying with statistics and not issuing a correction: bike-share injuries”, Phil Price, andrewgelman.com, June 17, 2014.
 “Hard Evidence: do bikeshare schemes lead to more head injuries among cyclists?”, Woodcock J. and Goodman A.; Theconversation.com ; August 28, 2014
 Health effects of the London bicycle sharing system: health impact modelling study, James Woodcock, Marko Tainio, James Cheshire, Oliver O’Brien and Anna Goodman. BMJ 2014;348:g425
 letter to American Journal of Public Health Editor, Dr. Mary Northridge, by K. Teschke and M. Winters, June 24, 2014
July 23, 2014
On Thursday July 17th, the SkyTrain system was shut down during the evening peak travel period due to a failed computer component. This left many passengers stranded both at SkyTrain stations and in SkyTrain cars for many hours. Then on Monday July 21th the skytrain system was brought to halt due to a tripped electric breaker protecting the SkyTrain’s operations centre. The power outage also halted the public announcement system
Having two skytrain melt down in a row is statistically improbable. Improbable but not impossible…drawing some hasty conclusions on the general state of the system based on exceptional event shouldn’t be done at this stage:
Some observers have been quick to link the skytrain glitches to lack of funding. We notice that the latest meltdown is linked to the extension of the Skytrain (Evergreen line work)…
Identifying the root cause of the trouble is a good step. Translink, which seems to have learnt how to manage crisis in Pyonyang, thinks it has then took the adequate measure: suspend the electrician whose is alledgely responsible for the tripping of the breaker.
We will note that if a breaker exists in the first place, it is to allow it to trip, and the consequence of a tripping should be known as well. so a first question
- Does the risk of accidental tripping of a critical breaker due to electrical work was properly assessed? and its corollary: Does the electrical work was appropriately scheduled to minimize risks on skytrain operation?
The handling of a crisis communication
A tripping breaker or something else shutting down a whole transit system is a rare occurence, but not something unprecedented:
During the great 2003 North east blackout, whole transit systems, in cities such as Toronto or New York, grind to a complete halt…
In such occurence, The question is: What is the response of the Transit authority and is it adequate?
- Does Translink expect people to roast in trains for hours without any information?
If a train evacation plan was in place, something one could have excepted to be decided in the minutes following the skytrain halt (a tripping breaker is a priori something quick and easy to troubleshoot, and the consequence on the time to “reboot” the system should be well know).
- Why Translink didn’t inform its customers about it?
Thought the passenger announcement system was down, medium like twitter was available (but used only to mention an unspecified “technical issue”). That brings us another aspect of the issue.
Is the Skytrain system rightly designed?
- In crisis situation, more than ever, communication is key: the passenger information system should be insulated of other control systems (be able to run on onboard battery…)
Wrong per design, is also the fact that a Skytrain “glitch”, seems always to bring the whole Skytrain system on its knees. The system seems to be too much centralized. The corollary of it:
The more the system expand, hence add complexity (be by mile of trackage or by number of trains in operation), the more the chance to have catastrophic glitches.
The occurence of it can be reduced by increasing the reliability of the system as is (that can be typically achieved by providing redundancy on key part …but eventually that will not prevent embarassing issues where the whole skytrain system break down, due to a too centralized management of it.
Better overall resilience could be achieved by a more decentralized system: having the different lines operated as much as independently as possible is a step in that direction . That could not necessarily means less over-all break down, but a break down could be of much minor consequence on the system (typically confined to one line). In that regard:
- With the advent of the Evergreen line (VCC-Douglas college), the Millenium line should be shortened to be (Watefront-Lougheed) which should reduce catastrophic break-down effect
- the poor design of the Lougheed station which can be already criticized for the lack of same platform transfer between future Evergreen line train (VCC-Douglas) and Millenium train (Waterfront-Lougheed), can also be blamed, for preventing to operate one line in total disconnection of the other in normal operation (excluding OMC access)
- We have to celebrate as an an eventually uninentended advantage, the fact that the Canada line is operated totally independently from the rest of the skytrain network
The Skytrain reliability is touted at 95%: that measures the % of train running no later than 2mn of its schedule.
A measure providing little meaning for the customer:
- train can run late, but as long as speed and frequency is maintained, the level of service for the customer is maintained.
The measure of the skytrain reliability doesn’t provide us with a good idea of how “late” or “slow” the 5% of trains not “on time” are.
The problem is that when a Skytrain is “running late”, it can very quikly means hour delay for the customer. In that light, 5% trains “running late” could be then considered as way too much (a bit like if a driver was facing incident like flat tire or engine break down once a month, but should feel content because the rest of the month, or 95% of the time, the drive is unevenfull…).
For matter of comparison, the reliability of french driverless subways is usually north of 99% 
To the risk to be at odd with Translink, a review to all of the above question is necessary: the findings could eventually help to reduce the occurence of skytrain systemic issues and more certainly will provide some guidance to help to improve the handling of such occurence in the future
 see Twenty Years of Experiences with driverless metros in France, J.M. Erbina and C. Soulas. As an example, the Paris automated line 14 reliability (percentage of passengers who waited less than 3mn during peak hour or less than 6mn during off-peak hours) is at 99.8% on the Paris automated line 14
 Per definition a “back-up” system is not working when the main system is…and back up system issue are typically discovered when we need it if not thoroughly and recuurently tested what involve significantly ongoing maintenance cost.
 As an example in Paris, each automated subway lines (taht is line 1 and 14 has its own central command center. That is also true of the Lille VAL system, which has 2 lines opened in 1983 and 1989