Review - Human Transit: How Clearer Thinking about Public Transit can enrich our communities and our lives, by Jarrett Walker

An observation from last September’s Australasian Transport Research Forum conference was the abundance of academics versus the paucity of practitioners.

I define practitoners as those who plan and operate transport routes or closely work with those who do. They have their own work and don’t write books and attend conferences as much as academics and bureaucrats.

Consequently it was refreshing to find a book on public transport service planning by an experienced practitioner. The author, Jarrett Walker, is a service planner and consultant to transport agencies in the US, Canada, Australia and New Zealand. His work was already known to me through his blog at humantransit.org

Having read books by academics such as Mees, Newman and Kenworthy, I was particularly interested in the different perspective that a practitioner might bring.

Academics thrive on research, teaching and (sometimes) political advocacy. However the affordability, practicality and acceptance of their recommendations may not frequently be tested.

Whereas practitioners need to be more practical and less theoretical. They must often work within existing resources; something academics might find limiting. Consultants can be practitioners too but won’t get work if not seen as useful.

In Human Transit, Walker describes himself as a plumber.

We don’t expect plumbers to tell us how to run our cities and our lives; unlike (say) priests, politicians and talkback radio hosts. They may hold values but cannot choose them for their clients. But they might be able to advise on the consequences of particular decisions; for instance the cheap quick fix versus the dearer but enduring repair. And they might point out that any option chosen must respect basic laws, like water flowing from high to low, for the system to work effectively.

City planners and developers deal the hand with which transit planners must work. Some decisions, notably with respect to density, are controversial. Walker, more than Mees, sees density as conducive to higher patronage. However he adds, correctly in my view, that location and geometry are equally critical when designing neighbourhoods for direct and efficient transport routes. To Walker these factors are public transport’s equivalent of the plumber’s basic laws. If disobeyed an area may never be easily or efficiently served by good public transport.

Transport networks themselves can be optimised to favour patronage or coverage goals. Networks that optimise patronage generally have direct, fast, frequent but more widely spaced routes, whereas a coverage-oriented network sacrifices directness, speed and frequency for short walking distances. Walker insists that transport authorities set a resource allocation policy between ‘patronage’ and ‘coverage’ routes.

Only after such priorities, and thus available resources, are known can the service planner design the network.

The book is a mine of simple but often neglected insights that would make public transport better. All are applicable to Melbourne. For instance the trade-off between directness, frequency and legibility on the one hand, and requiring that people change for some trips. We’re used to road maps having different thicknesses for different types of road, from lane to freeway, so why not do the same with transit maps, highlighting our most frequent,and thus most usable routes? And, on busy roads, the contribution of the humble pedestrian crossing to improving access to bus stops and the impetus it provides to gradually increase an areas’s walkability (and thus transit access).

Human Transit does what its title suggests. It forces the reader, from layperson to transport planner, to sharpen their thoughts and ask the right questions. I highly recommend it.

Human Transit is published by Island Press and is available via the link below.

Aural Timetables: A new tool for connectivity analysis?

A key topic here is transport timetables, especially where there are opportunities for legibility, frequent service or service co-ordination.

Those needing to make a connection typically have to juggle two printed timetables, or, more recently, use an internet journey planner which does a similar thing after comparing alternatives.

In both cases arrival and departure times are presented in visual format.

The visual approach is good for planning specific trips. It could be numerical (eg calculating connections from two columns of times, often in different booklets) or graphical (as used in train graphs, and I think proposed by Tufte).

However I'm unaware of anyone converting timetables to sounds and analysing the result by listening.

Yet aural timetables could offer some fresh insights. For example it provides a way of comparing multiple timetables simultaneously for patterns; something the eye is poor at as it can only look at one time at a time and make a subtraction.

The possibility of aural timetables has evolved from earlier analogies made between some audio/musical concepts (eg resonance, harmonics, time, beat and pulse) and transport timetabling (at least for timed transfer systems). The term 'harmonised headway' hints at this relationship.

More recently I built a drone machine as used by electronic musicians. This is a bank of variable tone generators that can make many interesting sounds and beat notes. I then saw the possibility of audio frequencies being determined by bus and train times at a particular interchange, unwittingly turning service planners into composers.

Such an instrument would be more advanced than my simple drone machine, most likely having a master oscillator and dividers to accurately provide for specific service frequencies. You would also need to shift the start and finish times for each route to reflect actual timetables.

Another approach is to do without special electronics and simply use an audio editing program. I used Audacity which features an audio tone generator just right for this purpose.

The video below explains the concept.

Unlike future videos this one is based on a hypothetical location to introduce the concept of a multi-route aural timetable likely to be useful for connectivity analysis. It starts off with a train arriving every 15 minutes. To this is added a feeder bus every 30 minutes, then another every 60 minutes. At this point the local network is harmonised and the rhythm is distinctive. Then a non-harmonised 50 minute frequency route is introduced and the rhythm (and regularity of connections) is upset. The per second pulse is restored when this service is rescheduled to run every hour. For passengers this means predictable waiting times and an effective frequency for trips involving connections no worse than that of the least frequent route.

You may need to replay this several times. First listen to tones of the same frequency to discern their interval. Once these are identified, listen to the intervals between tones (easiest at lower frequencies, eg 50 or 60 minutes).

Most significantly, note is how the 50 and 60 minute headway services start as being far apart, then arrive at once in the middle, then space further apart near the end. These actually follow a long cycle based on the lowest common multiple (ie a cycle length of 300 seconds here or 300 minutes in the real world).

Such cycles are too long to discern aurally, but a further speeding up may be required to pick this up. Conversely slowing down might help with higher frequency services.

The speed of playback affects how the mind sees these noises; either as individual beeps or rhythms different for each combination of service frequencies. This is similar to Morse code. At slow speeds (eg 5wpm) one must count dots and dashes whereas at higher speeds (eg 20wpm) each letter has a distinctive sound. The advantage of this is increased by the mind's limited memory (or persistence) of sound and memorised rhythms require less effort to distinguish and decode than counting dots. It is painful for a person proficient in the faster speed to return to the lower speed method of decoding.

The same applies to timetables converted into sound. Particularly marked is that the harmonised timetable example (15/30/60/60 minute frequencies) is easier to listen to than the non-harmonised example (15/30/50/60 minute frequencies). I think this is because the harmonised pattern has a cycle recurring every 60 minutes (1 second) whereas the non-harmonised pattern's cycle only repeats every 300 minutes (5 seconds). A series that repeats every second is easy for the brain to sync to, whereas a 5 second long rhythm would be much harder.

What are the strengths and weaknesses of listening to (rather than looking at) timetables?

For precise connections between particular services I still think that either one of the visual approaches are better. However when it comes to examining headway compatibility at stations or interchanges, the aural approach has advantages. Here we are examining the state of connectivity by literally taking its pulse.

Government database content and getting to work

The Victorian State Government has made available data on a range of topics. It is hoped that this will encourage entries in the App My State competition.

There are two data sets that directly concern public transport. Transnet is a database containing stop data and timetable information for most public train, tram and bus services in Victoria. It is maintained by Metlink. In addition another file contains stop data only. It is important to note that both files are frequently updated and there's a chance that what you download today may not necessarily be the latest version. Nevertheless it will still be useful for competition purposes.

The format of the above information may be unfamilier to those whose computer experience is limited to basic Word and Excel use. You will need to be into databases to get most benefit from this data.

Other information provided also has relevance for transport. An example is Suburbs in time for which data is presented in Excel format.

Suburbs in Time data is a bit old, based on the 2006 census, but is still interesting as there is a census question related to travel to work. For example, in 2006 20% (574/2661) of employed Glenhuntly residents took the train, versus barely 3% for Frankston (450/14898). And for Frankston just 5 more people took the train in 2006 than 1996, compared to a 221-person increase for Glenhuntly.

While there are differences such as Frankston Station's large catchment and the possibility that some Glenhuntly residents would board the more frequent service available at either Elsternwick or Carnegie, it does indicate that even mature suburbs can generate high patronage growth. Brunswick, another suburb attractive to city workers, has shown even more impressive growth, but for tram rather than train. As an outer growth area, Hoppers Crossing would have expected high patronage growth, and it did get some, but at least up to 2006 its growth has been modest relative to the high population growth. This is likely due to the distance of most local employment areas from railway stations, limited bus services (soon to be increased) and high car and parking availability.

The proportion who walked is another interesting stat. Walkable suburbs have a high proportion of walkers whereas less walkable suburbs do not. For example in 2006 202 Werribee residents walked to work (compared to just 74 who got the bus). Still a small proportion of the 16251 employed. Inner Werribee (both north and south) is a long-established and walkable area.

Hoppers Crossing is less walkable but has a similar workforce and proportion of walkers to Werribee. Possibly this could be attributed to Werribee Plaza (actually in Hoppers Crossing), which is a major employer and is walkable from some residential areas.

In 2006 Rowville had the same number employed as either Werribee or Hoppers but only 148 walked, about 25% less than either Werribee or Hoppers. It's a pedestrian-hostile neighbourhood and the largest employer would be Stud Park Shopping Centre. This is not walkable from most of Rowville and is smaller than Werribee Plaza. Rowville also has higher incomes and more multi-car households than Werribee.

Reservoir is another large suburb with similar numbers of employed persons as Werribee, Hoppers Crossing and Rowville (about 17000). Though there are some pedestrian-hostile intersections, much of the suburb is a walkable grid. The number of walkers to work here was 246, ie about 25% higher than Werribee and about 70% higher than Rowville.

While detailed knowledge of workplace locations would be desirable for further research, the above numbers indicate that suburb walkability does have some bearing on the numbers of people who walk to work. However given that work trips are often longer distance than other trips such as shopping and recreation, and this would work against walking, the extent to which non-work trips are made by walking is also important for a true idea of walking's share, and one not answered by the census data.

Two items about service planning

1. Transport revolution to get city moving foreshadows a plan to rethink road space to more efficiently move people and goods on existing roads. It could also be of interest if it applies a 'network thinking' approach to roads, as it may provide useful insights for public transport planning as well.

Until this latest document comes out, it might be worth looking at 2007's Guidelines for Network Operations Planning provided via the City of Stonnington website for some background.

2. Another good read is the TCRP Scheduling Manual. Produced for the US Transportation Research Board, the research for it was led by an Australian, Phillip Boyle. Phillip will be known to those who attended the recent Melbourne bus review workshops in some areas. If you're short of time, just read Chapter 3 for a good 'how to' introduction to scheduling.

Network Design for Public Transport Success - Theory and Examples

An academic paper from Nielsen & Lange covering many of the service planning topics such as legible routes, pulse timetables and timed transfer networks discussed here. A 'must read'.

Quantifying the benefits of transit improvements

A recent research monograph featuring the Perth-Mandurah railway provides some useful ways to quantify the benefits of public transport infrastructure and service improvements.

Spacial Network Analysis of Multimodal Transport Systems: Developing a Strategic Planning Tool to Assess the Congruence of Movement and Urban Structure from Dr Jan Sheurer and A/Prof Carey Curtis has a long title and is an even longer read. While heavy going for the general reader, the effort spent on it will be well rewarded, with a method and insights applicable everywhere.

Examples of analysis techniques from the paper include:

* The concept of impediment values for movement between centres. Fast and frequent train services have the lowest impediment values while slow and less frequent bus routes have the highest
* A network analysis based on service frequency between suburban nodes, considering transfers only where services are every 15 minutes or better.
* A measure of relative public transport accessibility from various suburban centres (based on population reachable within 30 minutes travel time)
* 'Degree Centrality' or the average number of transfers required to reach other areas

A few practical messages from the paper:

* 'The network effect' where improving transport serving one area (in this case southern suburbs and Mandurah) benefits access across the entire network, not just the area in which the line is built
* New lines can speed travel, not only for CBD trips, but also, if operated in conjunction with improved buses (as happened in Perth), for cross-suburban trips as well.
* The importance of locating major trip generators next to (not 1-2km from) railway stations. The number of people within a 30 minute contour is 376 000 at Murdoch Station compared to only 177 000 at Murdoch University. Similarly Joondalup Station is accessible to 164 000 people, versus just 28 000 for the Joondalup campus of Edith Cowan University (both universities are just outside the respective station's pedshed). For Melbourne this method shows (i) how poorly accessible the proposed Craigieburn Town Centre (also just outside a station's pedshed) will likely be compared to the station itself and (ii) the benefits of a station at Southland Shopping Centre.

Sheurer and Curtis have produced an excellent paper of significant practical use. Leave your thoughts on it as a comment below.