Wednesday, February 10, 2010

Establishing consumer benchmarks of service quality in public transport

Getting a consistent frequency and even spread of services across each hour is a key factor in quality benchmarks from a consumer viewpoint. Not such a problem on Wilmslow Road in Manchester, claimed to be Europe's busiest bus corridor with buses every 30 seconds at some times in some sections. [Even so it appears one old codger losing his specs in the doorwell of a bus can bring everything to a halt!]
Photo Wikimedia Commons

Recently I raised, again, the issue of quality control in public transport planning, particular in regard to south Christchurch Saturday night and Sunday services. This article takes that thinking a little further

I gave up cars ten years ago, after my kids became adults. I also often lived without a car, in three different cities before they were born, whilst I was still in my twenties. So I am an expert in this field! I am not entirely joking. Who knows better the quality of a bus service than the consumer? Anyone catching buses on  a regular basis, day, night and weekends too, soon becomes intimately aware of the nature and quality of service to their area and its various quirks.

Everybody in the world knows the common phenonema that you wait and you wait and wait for a bus, and then two or even three buses arrive simultaneously. It is a standing joke, part of the derogatory bias that allows the average person to dismiss buses as a second rate or impractical form of transport. Of course in big cities or in peak hour service intensity it is probably symptomatic of buses bunching up - as one bus service gets later it starts to pick up more and more passengers, including people that would normally have got the following bus service; and of course the next bus service load gets lighter and lighter until that bus catches up with the bus in front. This can involve multiple buses if services along a corridor are only anyway a few minutes apart. Leo, a bus driver I worked with in the 1970s told me when he drove buses in Los Angeles back in the 1950s on certain street corners they had men stationed as timekeepers who by pointing upwards or downwards signalled to a bus driver to speed up or slow down to maintain a consistent flow pattern and gap between buses. No doubt minature computerised traffic lights, discreetly located on a power pole, or indeed, on the dashboard of buses, could achieve the same effect today in cities where multiple services along the same corridor may be only minutes apart (friends who lived a year and a half in Manchester said there was a bus every 30 seconds on their local corridor - said to be the busiest in Europe). ps Such is the wonder of Wikipedia, the most amazing encylopedia in history, I discovered even this obscure claim has an article -here and photo above

In small cities where services are typical less than 8 per hour (a bus every 7-8 minutes) on any one corridor the phenomena of all "long gaps, several buses at once" comes back mainly to delays brought about by traffic congestion and/or - if the corridor route served by multiple buses services is longer than a kilometre or two -  poor scheduling. 

People often say "we have a good bus service" (of course that doesn't mean they use it!) but I think compared to what? What standards are we measuring against - other bus systems? the bus systems of 50 years ago?  the expectation that buses are only a supplementary sort of transport, a sort of social charity for which ever person dependent upon them should be grateful?  I tend towards the thought that all forms of transport are heavily subsidised, with enormous double standards applying to support car addiction, and public transport could step up to the plate and be many many times more effective than its current minor supplementary role. But it still operates with a large element of "old fashion public service, good enough for the peasants" attitude, seen as a collection of disparate routes and varying times, even it seems by planners, rather than a sophisticated and dedicated, holistic network, of predictable system wide patterns, intermeshed like cogs in clock, so well done that it can be taken for granted, understood even by those who don't use it. For me this includes - indeed requires -  a bottom line commitment that within time bands [Sundays; or before 9 am weekdays, evenings etc] there is a guaranteed consistency of service.

I have played around in my mind for a long time with whether it is possible to arrive at some rule of thumb benchmark for quality standards in small city transit services, what the passengers (and taxpayers, local tax or ratepayers) might deem a minimal standard for service consistency and effective use of resources. Perhaps there are industry standards existing somewhere in the world but if there are, they are either not being applied in Christchurch or fall woefully short of what I'd consider bottom line expectations for consumers and tax payer funders. It came to me yesterday that a good formula might be expressed as "no gap between services serving the same or similar key functions on significantly shared route corridor or from a significant shared junction should be greater than one third in excess of the averaged even spread headway ratio of total services per hour." Phew!!

This sounds very complicated but is actually absurdly simple - if there are two services an hour then the averaged (and ideal) even spread headway ratio is a service every 30 minutes; a quality control measurement would insist that the gap between services should not be greater than one third longer in time than of 30 minutes = 10 minutes. In other words if the pattern of combined service delivery is greater than 40 minutes it is not deemed an effective use of resources and falls below the quality service benchmark. In this scenario if the ideal of a service every 30 minutes exactly can not be met, the goal must nonetheless be to achieve a service frequency of no greater inbalance than service A being followed by service B at 40 minutes or less. That is to say; in  worst case scenario local residents would have a pattern of service A - wait 20 minutes - service B - wait forty minutes -service A again. If not they might justifiably say they are not getting a quality service. Nor are their taxes(rates) funding effective resource use.

If there are 4 services per hour then the same quality benchmark (maximum excess of averaged headway no greater than 33%) would be 15 minutes ideal, variance no greater than than 5 minutes (one third) or a pattern of A - ten minute wait - B twenty minute wait -C ten minute wait -D - twenty minute wait - A ... (next hour etc). In the case of eight services or more per hour along a shared corridor then average ideal headway is 7-8 minutes and the quality benchmark would be in no case is there a gap of longer than 10 minutes.

I doubt whether many schedulers would embrace this idea - indeed I can imagine schedulers and planners and administrators squealing like stuck pigs with such conditions imposed!!
I imagine it is difficult enough job already, trying to match up the many variables involved, without adding these further conditions.  We are talking trying to achieve perfection here, and as the saying goes perfection takes a little longer! Or perhaps something a little closer to perfection takes twice as long to arrive at solutions as conventional scheduling. In the ultimate situation to get a top quality bus service in Christchurch involves a pro-active holistic approach, including route patterns,, and identifying every key shared corridor, or major intersecting point (mainly malls) or larger facility served by more than one route. It would mean looking at a whole city network, instead of a piece meal approach, a time consuming exercise that is probably no where covered in any annual budget and runs contrary to the whole pattern of renewing tenders for routes (and making route changes on those routes) in clumps of every 3 years.

As a full time bus user I run up against constant anomalies (in what is generally a fairly good bus system) that seem to me would never pass muster if quality controls were being rigorously applied. The sort of benchmark suggested here is achieved in some parts of Christchurch, widely breached in others. This is particularly so, of course, outside peak hours when service frequency on any route is lower and therefore gaps between services are anyway going to be much greater. A time when good integration and fierce commitment to meeting quality benchmarks is particulary important if public transport is ever going to make inroads into car usage. When that doesn't happen the syndrome "there's a really long wait then they all come at once" ridicule that discredits bus services is being directly fostered by the planner decisions, undermining their own efforts to promote bus use.

I doubt whether the measurement above will mean much to anyone in the bureacracy but I will certainly promote and apply it, a consistent formula for myself and any other interested consumers to really evaluate the quality of a service or resource use being offered.

I will in my tiny way continue to campaign for quality transit benchmarks - the opposite sort of benchmarks from the ones you get on the bum from sitting at a bus stop too long! Unnecesarily!

No comments:

Post a Comment