This chapter summarises what I have learned with regard to the art of Transport Planning. This is really about making choices and in so doing reflecting some underlying values, principles and features; including: connected grids, modes, value of time, fares, the importance of service frequency in urban areas, coverage vs ridership, service and network legibility and the implications of post Covid working patterns.
In this chapter I cover:
- 12.1 My Transport Planning journey
- 12.2 Choices and compromises – especially ridership V coverage
- 12.3 Value of time (and Quantum Physics)
- 12.4 Public transport grids, networks and segregation
- 12.5 Service frequency
- 12.6 Transport modes
- 12.7 Network legibility & simplicity
- 12.8 Post Covid, flexible working & transport demand
- 12.9 Fares and subsidies
- References
12.1 My Transport Planning journey
When I started my Metro journey in 2010 I had little formal knowledge or experience of Transport Planning as a professional discipline nor of the academic work and research that underpins it. I had little experience of transport modelling, multi criteria appraisal and WebTAG and WelTAG were unknow to me. I had been driven by my own personal assessment of the transport related economic development issues and opportunities in the wider Cardiff Region, based on what I had seen and observed in other places – in effect my own personal qualitative socio-economic benchmarking. I describe my approach to Transport Planning in 15.3 Mark Barry’s transport planning
Despite over ten years working in this space, I certainly don’t consider myself an expert in the art, or is it science of, transport planning; I lack the objectivity, attention to detail and patience of transport planners, and planning and regeneration professionals. What I will say, is that I have learnt a great deal – mostly by picking up and learning from experts in the field[1]. This includes those hard-pressed officials I have worked with in southeast Wales; from within Local Authorities, Welsh Government and the major consultancies operating in the area , WSP, Mott McDonald, Aecom, Atkins, Capita, Arcadis, etc), as well as smaller local players (e.g., The Urbanists, Robert Chapman & Co).
I can’t overlook the academic experts I have worked with at Cardiff University and especially The School of Geography and Planning[2]. I also have to acknowledge the increasing expertise and capability of TfW and its Planning and Development Directorate[3] under the leadership of Geoff Ogden. I have also leant heavily on the work of internationally recognised practitioners; for me most notably Jarrett Walker[4] and his famous blog site, Todd Litman of the Victoria Transport Planning Institute[5] and academics like Robert Cervero[6]. I recommend reading all; Jarrett Walker’s Book Human Transit[7] is, I think, an essential read for all Transport Planning students and practitioners. Whilst nearly twenty years old the HiTrans series of guidance[8] for transport systems, networks, etc is also a hugely valuable source of insight.
What I wanted to present here is a summary of the key lessons and observations that I think deserve a broader public airing with regard to Transport Planning in Wales and especially the Cardiff Capital Region. So below, I have taken and updated and expanded the section of the CCR Rail Passenger Vision[9] I prepared in 2021 and in further blogs on my WordPress site.
12.2 Choices and compromises – especially ridership V coverage
When developing schemes and business cases, transport planners have to weigh up and assess a wide range of costs and benefits and reflect the needs of current and potential passengers, as well as the needs of operators and governments. Contributory factors include decarbonisation, congestion, demand (actual and latent), capacity, Persons of Reduce Mobility (PRM) compliance, station design, integration, service frequency and costs (both capital and revenue) as well as broader considerations such as economic development and regeneration. There are few “right answers”, only choices and implications thereof, shaped by policy priorities and, as Jarrett Walker set out, values.
Nor can we ignore the constraints and limits of available funding – there is never enough money. This includes both capital funding (capex) – so what we need to build more infrastructure like new routes and/or provide more capacity, and operating costs (opex) – what is needed to actually run and operate public transport services to cover things like vehicle maintenance, track maintenance, fuel and staff costs. It’s the latter over the longer term that is often the more insoluble funding challenge. Collectively these all influence our choices, for example:
- Services that aim to maximise coverage (and so serve as many places as possible), especially where demand is low, can add to opex per passenger and overall subsidy and so with limited resource result in lower service frequency
- Services that maximise passenger numbers – ridership (serving the most populous places with the most services) typically result in higher service frequency, lower cost per passenger & more efficient operations, but may not serve everyone at all times (See Figure 161 Figure 162) I recommend the work of Jarrett Walker[10] who expertly and simply set out the ridership V coverage challenge in his blogs, books and videos.
- Service with “turn up and go” frequency (typically at least 4tph), especially where local catchment is high can increase demand and reduce opex per passenger; however, in areas of lower total catchment or off peak, can add to opex and increase costs per passenger
- Services with free, low or subsidised fares can attract more demand but make incremental service expansion (that may be needed to satisfy the increased demand) more costly
- Segregated operations (via rail, bus lanes, etc) which may have high capex, enable faster more reliable & attractive services (so higher demand & fares) with lower opex.
Choices always have to be made, and transport planners do their best to develop affordable schemes and business cases that deliver most value to most people whilst also addressing their values and priorities. In so doing they have to work with people across organisations and consider spatial & economic geography, transport planning process and political realities.
Figure 161 Credit Jarrett Walker, “Human Transit” (Island Press), Ridership Vs Coverage
Figure 162 Credit Jarrett Walker, “Human Transit”(Island Press), Ridership Vs Coverage
Transport planners are also increasingly grappling with how to ensure equity and inclusivity as well as effective engagement in appraisal and decision making; something that has become more important in Wales as a result of the Well Being of Future Generations Act[11].
In respect of some of the broader social and equity considerations, Todd Litman published two insightful papers in 2021 that help provide a more systematic basis for addressing some of these questions. His September 2021 paper[12] explored the role for more equitable public transport in a post Covid world; his December 2021 paper[13] expanded his earlier work to provide a more robust basis to include distributional impacts in transport planning and makes the case for more effectively and fairly apportioning external costs (including measures like road pricing), and how we serve disadvantaged groups and address social injustice.
Transport planners also have to objectively assess a range of alternative measures to deliver the same outputs. This is what WelTAG[14] (Welsh Transport Appraisal Guidelines) tries to achieve. This can be more an art form than a science, although the increasing application of sophisticated transport models is helping with decision making.
However, it is also worth noting, whilst Transport Modelling is a valuable tool in helping support decision making, one should be cautious. As Paul Chase at TfW once advised me, “one should view the output of a transport model as one might treat a weather forecast; it may promise sun, but I’ll pack my coat just in case”. Paul was responding to an article by Matt Lowrie[15] which contained a relevant warning “…the issue of why the transport profession has abdicated responsibility to transport models so much.” I’ll pack a coat just in case.
For a more academic history of the development of method, models and theories underpinning travel forecasting over the last seventy years, “Forecasting Urban Travel”[16] is worth a look.
Today, more important than processes or tools, perhaps the primary consideration to acknowledge, especially given the decarbonisation challenge (now overtly referenced in Llwybr Newydd – The Wales Transport Strategy[17] and Net Zero Wales[18] ) is that we need to develop a transport network and services that can attract some of the approximately 80% of people who pre-Covid chose to use their cars. There is clearly a large untapped market for public transport, so we need a better product designed more around what those not currently using public transport want and perhaps less so those already using public transport.
Almost equally important is an urgent need to improve urban air quality which has been degraded by excessive car use(not just tailpipe emissions) As set out earlier, given these pressing challenges, I think the case for Demand Management measures (including road pricing ) is overwhelming and has to influence how we “plan” transport.
Finally, I would add that in my experience, in 80% of cases the interventions needed are (for me at least) pretty obvious. Frustratingly we sometimes apply the transport planning tools, methods and process best suited to the more complex and less clear 20% of situations to the less controversial schemes adding unnecessary time & cost.
12.3 Value of time (and Quantum Physics)
A cornerstone of transport planning and modelling is a metric called “Value of Time”. The DfT[19] have set out that values of travel time reflect:
the amount of money a traveller is willing to pay to save time; and the benefit a traveller would receive from being able to put ‘saved’ time to alternative uses following a transport investment.
Travel time savings typically account for a large proportion of the benefits of major transport infrastructure. For this reason, they play an important role in policy making and investment decisions.
There are different value of time metrics used in different circumstances as described for example in a market research report for the DfT[20]. In fact, transport modelling can get very complex, very quickly and using VoT guidance, sometime small numbers can get amplified into big ones. This is appropriate in many cases, but not all and can sometimes lead to poor decisions.
As a metaphor I want to illustrate perhaps some of the failings of aggregating many small changes in this way.
A long time ago, I studied Physics in Manchester, and first encountered the non-intuitive nature of Quantum Physics. I didn’t really understand it then, read some books after University and thought I did…but didn’t. In fact, the whole subject is perhaps best described by Nobel Laureate, Richard Feynmann, who is purported to have said, “If you think you understand quantum mechanics, you don’t understand quantum mechanics”.
It really runs counter to our common sense understanding of the world. Anyone who has grappled with the implications of the double slit experiment, non-locality and spooky action at a distance, will concur and that’s before we get to Schrodinger’s dead and alive cat. Yet the mathematics wrapped around Quantum Physics provides us the most accurate tool to understand a sub-atomic world that would otherwise remain hidden from human exploration.
Many have tried to apply some of the implications of Quantum Physics to new age interpretations of the world…most of which I view as woo. Despite that, I’d like to use one aspect of Quantum physics as a metaphor for an issue impacting transport planning and especially the treatment of the “value of time”.
First, let’s focus on the Photoelectric effect; and the theory set out by Einstein in the years that followed Planck’s [21] (the originator of Quantum theory) bombshell revelation that electromagnetic energy could be emitted only in quantised form. Simply put electromagnetic energy can only be a multiple of an elementary unit (later called photons) where the energy E = hv where h is Planck’s constant and ν is the frequency of the radiation.
This insight also had to complement the clear evidence of the wave like characteristics of electromagnetic radiation and so manifest the essential wave/particle duality of EM radiation which is a key feature of Quantum physics.
This then brings us to Einstein’s[22] insight into the photoelectric effect[23]. The photoelectric effect is the emission of electrons when electromagnetic radiation, such as light, hits a material. Electrons emitted in this manner are called photoelectrons.
The revelation Einstein introduced was that the ability of incoming light to generate photoelectrons (so a current) from a suitable material depends, not on the number of photons (so the intensity of the light), but of the frequency of that light and so the energy of individual “particles” of light. That energy had to be of a sufficient level to “dislodge” an electron from the material. No matter how many photons (or intensity or their aggregate energy) no photoelectric effect will be observed until the frequency and so the energy per “photon” reaches a certain level. Einstein also observed, building on Planck’s insight that the emissions of such electrons were quantised and not on a spectrum.
Now let’s look at Transport Planning and the Value of Time[24] (VoT). Very roughly, when transport planners are estimating the transport user benefits of a transport intervention, they normally multiply the journey time savings by a VoT metric. There are different values to be used in different circumstance, and transport models do accommodate different elasticities of demand in some circumstances. However, we are sometimes left with counter intuitive outputs from VoT calculations. For example, the WG were recently obliged to assess (using HMT Green book guidelines) the economic impact of the 20mph limits now in place in Wales.
Over 60 years that formally produced a disbenefit of over £4Bn[25] based on the table in Figure 163
Figure 163 Table from Senedd explanation note re WG 20mph limits
One can see that the total impact is made up by aggregating 000s of very small changes, over 60 years, of less than two minutes to journey times. The question is, in the real world, is the calculation and output value in any sense “real”. In most circumstance, I think not.
For me this is like 000s of photons whose frequency is not sufficient to generate an electron via the photoelectric effect. I assert that a small change to a big number generally does not in fact have any meaningful impact on people’s choices. There ought to be a threshold (absolute and as a proportion) above which the impact of the change in journey time does have an impact – but below it does not?
Look at this, what is in aggregate the biggest impact?
10 people being able to go 20 minutes faster on a journey that used to take 60 mins (a 33% reduction in journey time) – so 10*20mins = 200Min
OR
200 people able to go 1 min faster on a 60-minute journey (3.3% journey time saving) – again so 200 *1min = 200mins.
I assert that whilst the maths gives the same number for the aggregate benefit, it is only the first example that has a meaningful impact on people’s behaviour and choices. And it does not matter how many people save 1 minutes on a one-hour trip (there could be 10,000 people) there is still no impact.
This is a common criticism of transport planning and appraisal where big numbers are often generated like this, by aggregating thousands or even millions of small incremental values over years and even decades. This is how most roads schemes were approved.
So, like the photo electric effect, we need to perhaps modify our approach and recognise the “quantum” effect, and the minimum required “change” in journey time sufficient to actually have an impact on people’s choices and behaviour. Now I don’t know what that “value” is or should be. However, without this factor, we have used (in my view) a flawed methodology that has resulted in us building 000s of miles of roads and degrading our public transport (let alone failing to capture and quantify the many wider benefits of public transport use.).
I think this is the Value of Time catastrophe – something physicists will understand[26]
As a final point, we need to remember that Quantum Physics is based on statistical probabilities that can be (very) accurately modelled. In contrast, economics and transport planning are based on much more unpredictable human behaviours; yet we use transport models and supply & demand curves as if they were also describing underlying and predictable features of a physical science.
We need to be careful that decisions on major public investment are not overly swayed by mathematical interpretations and presentation thereof, that in some circumstances, have limited real-world merit.
12.4 Public transport grids, networks and segregation
Today in Wales (and anywhere outside London – apart now from Greater Manchester) our transport systems have and are being run by multiple operators planning and managing their own networks, often on a hub and spoke basis, with no real attempt to connect/integrate these networks and services. In fact, competition regulation is specifically designed to prevent uncompetitive integration[27]. This is one of the legacies of bus deregulation in the UK in the 1980s and rail privatisation in the 1990s – albeit there is more central control and regulation in the rail industry.
This fragmented offer is confusing for passengers, generally results in less coverage, adds to vehicle miles operated per passenger and increases opex and subsidy per passenger. In the latter case, sometimes public subsidy ends up supporting competing suboptimal services, especially rail v bus. For urban bus networks the hub and spoke model often leads to an oversupply of services on some routes and an undersupply on others.
Is there a better way?
Yes, there is value and efficiency to be gained by developing public transport services in urban populated areas using integrated multi-modal grids of rail and bus with high quality interchanges. I am not being prescriptive, there are many forms a grid can take (vs the more simplified manifestation below Figure 164). It really is about enabling more coverage for PT and more efficient operations thereof, using interconnected multi-modal services that minimise interchange penalties through high quality interchanges and high frequency component services.
The more efficient grid approach is simply illustrated in Figure 164 Figure 165 below. In urban areas grids are more efficient to operate as typically fewer vehicle miles are required to serve a larger population. However, to secure a positive passenger experience grids need high quality interchanges between component services; this also means that such component services have to be of sufficient frequency so that “wait” times are minimised and do not deter patronage. Typically, this means at least four services an hour and often more in densely populate urban areas (Anyone who has used the London underground will understand this type of grid service). As set out earlier the HiTrans guidance for network planning[28] is an excellent source of insight, as is Jarrett Walker’s book, Human Transit.
The challenge for each of Wales’s regional transport and/or Metro projects[29] (and perhaps most especially in the Cardiff Capital Region given the larger and more dense population), is to develop interconnected and integrated (esp. fares and ticketing) multi-modal grids of rail and bus which appear to the passenger as a single network.
In fact, it should be explicitly stated that many of the bus service improvements (via network redesign, BRT, bus lanes, fares/ticketing, etc) being developed for Wales post Bus Reform world, also require rail frequency enhancement so that they have something to “integrate with”.
For example, this is why it is important to enable “turn up and go” rail services of at least 4tph (and ideally 5 or 6 tph) vs the 2tph now on the City and Coryton lines in Cardiff (and so commensurate with the local demographics and potential demand).
Figure 164 Service from everywhere-to-everywhere Vs Grids V Hub & Spoke
The key features of a more efficient grid approach (so operating fewer vehicle Kms and with higher passenger numbers – PAX) include:
- Strategic network of integrated “arterial” rail and bus/BRT services
- Mode agnostic – so the right mode for the right corridor
- Network designed with interchanges (rail, bus and active travel)
- Component services with a minimum frequency of 4 services per hour (ideally 5+)
- Local Bus “capillary” services integrated with the strategic regional network
- Integrated multi-modal fare and ticketing AND capped PAYG
- High quality “last mile” AT access to network stations
Figure 165 The multi-modal integrated grids we need for our Metros in Wales
It is also worth emphasising the importance of segregated public transport services through the provision of infrastructure, road or rail, that limits interaction with other modes, especially cars, and prioritisation over other road users.
The ability to operate faster on segregated alignments (via bus lanes/BRT as well as fixed rail) reduces opex whilst at the same time providing the passenger a more reliable, quicker and attractive service so increasing demand and fare box. Put simply, if you can double the average speed of a bus service you only need half as many buses to deliver the same service frequency; offering a very significant operational cost saving whilst increasing ticket revenue through the delivery of faster and more reliable services that attract more passengers. To be clear increasing the average speed does not mean that buses have to travel any faster than they do now in urban areas, it means we remove the pinch points that slow them down or result in buses being caught in congestion so we can increase the average speed of a route/service.
For example, in Wales, with the work ongoing to enhance and integrate our bus ecosystem, one of the quickest and easiest things we can do is introduce a lot more bus lanes and bus prioritisation; Swansea, Newport and Cardiff should lead the way. With braver local politicians this simple measure applied on a more ambitious basis could help transform the public transport offer, especially, as is planned, when integrated with more strategic regional Metro rail services.
The application of the grid concept must also change how we think about specific stand-alone schemes, especially in respect of demand analysis and transport user benefits. For example, narrowly defined business cases and demand analysis for say a cross-valley link between Ystrad Mynach and Quakers Yard or the Coryton to Radyr connection in Cardiff, may, when assessed narrowly, only generate relatively minor additional transport user benefits based on historical flows.
However, both these sections can play a fundamental part in delivering a “regional Public Transport grid”, as they can support trips to/from a far higher number of Origin/Destination (O/D) points across the region Vs those just along the route. This is the network effect and can generate much higher increases in patronage than is often predicted using current guidance.
The earlier mentioned HiTrans network guidance also noted that the network effect can deliver elasticities of up to 5 vs the more commonly used 0.5 to model incremental changes more common in the rail industry Figure 166.
The same network principle applies to the package of further stations TfW have proposed for the Core Valley Line (CVL) network following the completion of the current transformation in 2023/24.
This is why it is sometimes more effective and efficient to develop business cases for larger packages of interdependent interventions Vs many smaller individual schemes.
Figure 166 From HiTrans Guidance re Network effects from “Planning the networks
12.5 Service frequency
Anyone who knows just a little about Transport Planning, passenger behaviours and the geography of urban areas, will appreciate that offering a service every 30 minutes for trips of probably less than 15 minutes, is not going to attract many passengers. Whilst people are generally happier to wait longer for longer trips, so up to 30 minutes perhaps for a journey of an hour or more, they are less inclined to do so for shorter trips. There are plenty of papers and articles out there[30] supporting that assertion.
A recent study by the Institute of Transport Economics[31] in Norway is instructive, including the impact of a number of interventions on demand, including service frequency. They assessed the Public Transport (PT) service characteristics that need to be in place in order to achieve certain PT market share levels among persons with access to a private car; ranging from a strongly competitive alternative to the car to a bare minimum service, which mainly serve those without a travel alternative.
They found for Norwegian cities other than Oslo (Oslo results were similar with overall higher PT shares):
- PT shares over 30 percent: The travel time ratio between PT and the car needs to be 1.5 or lower. In addition, there must be no interchanges, high service frequency and short distances to stops/stations
- PT shares between 20 and 30 percent: This is achieved with a travel time ratio below 1.5, maximum one transfer and high frequencies (more than 4 service per hour). This should be the target for urban PT services in Cardiff itself
- PT shares between 15 and 20 percent: Travel time ratio can be between 1.5 and 2.5, maximum one transfer and medium frequencies (approximately four departures per hour) This should be the target for PT services in the wider Cardiff Capital Region
- PT shares between 5 and 15 percent: Travel time ratio between 2.5 and 3.5, 1–2 transfers, lower frequencies and long walking distances to stations
- PT shares below 5 percent: Travel time ratio over 3.5, several transfers, low frequencies and long walking distances to stations.
Transport planners will be very familiar with the use of elasticise to try and predict demand based on increases in service frequency. However, evidence suggests that in some circumstances demand elasticities vary depending on the service frequency; for example, a TRL based study in 2005[32], found:
“Service frequency also has a strong impact on public transport demand elasticity. Elasticity for low frequency services is greater than for high frequency services. Cheung (cited in Booz Allen Hamilton 2003) found elasticities for lower frequency services were up to four time greater than higher frequency services”
A recent paper by Todd Litman[33] also noted the variability in elasticities,
“The elasticity of transit use with respect to service frequency (called a headway elasticity) averages 0.5. There is a wide variation in these factors, depending on specific conditions. Higher service elasticities often occur with new express transit service, in university towns, and in suburbs with rail transit stations to feed”.
In summary, from the data and studies I have seen, elasticises can range from less than 0.5 (for minor incremental changes to an already high frequency service) to as much as 5.0 (when network effects and interchange are considered) Figure 167.
Figure 167 Range of demand elasticities vs context
This data from Cardiff is instructive as it seems to reflect the analysis above in that there is clearly a link between station patronage (PAX) and service frequency. Noting that the Office of Road and Rail (ORR) Station PAX data is not always the most accurate method to measure station patronage as it’s based on ticket sales which often don’t correspond to actual trip origin and/or destination points.
Figure 168 Selected Station 2018/19 PAX in Cardiff
Just picking three stations helps emphasise the point:
| Station | Service Frequency now/planned with Metro | 1km catchment pop. | Approx annual PAX (pre-Covid) |
| Llandaf | 6tph / 10tph | 12,250 | 600,000 |
| Birchgrove (Coryton Line) | 2tph / 2tph | 14,000 | 70,000 |
| Waungron (City Line) | 2tph / 2tph | 13,750 | 100,000 |
What one can infer from the above is that:
- 1Km catchment populations around the urban stations in question are all broadly similar at 13,000 +/- 3,000 and with similar socio-economic characteristics
- Those stations with at least 4tph, average over 3 times the PAX than those with just 2tph
- There is clearly an opportunity (re-enforced when one also considers the academic data above) to secure much more PAX at those stations in question if their services could also secure a frequency of at least 4tph
Given this, I suspect traditional modelling and calibration thereof, understates the potential demand at some Cardiff stations significantly. I think in more granular situations such as this, then socio-economic benchmarking can be a more accurate guide to demand than a pure transport modelling approach.
The reality is that in densely populated urban areas, without an attractive public transport offer many people will almost certainly get into their cars instead; the importance of service frequency to attract passengers in these circumstances cannot be understated.
For us in the wider Cardiff region we really ought to be targeting “turn up and go” service frequencies of at least 4tph and ideally 5 or 6tph – especially in the urban core of Cardiff. As a comparator, the Manchester Metrolink offers at least 5tph at most stations and more at those serving multiple routes. Similarly, the Newcastle Metro is also planned around services every 12 minutes (so 5 an hour). The experience from the Bury-Altrincham line on the Manchester Metrolink when it opened in 1991/92 is that that patronage on the new higher frequency and faster LR service was over double (over 14M passengers with the biggest increases in the off-peak) the pre-Metro heavy rail service (which was about 7M passengers per year).
This further insight from Jarrett Walker is also instructive (and relevant in Cardiff) re frequency.[34]
The conceptual problem is that as long as our rail bureaucracies understand the peak commute to be their primary product, they will continue to care about running time more than they do about frequency. Running time matters more than frequency only for relatively long trips (because we tolerate longer waits to go longer distances) and for rigidly scheduled trips such as classic commutes (because we select a particular schedule trip to use). Everywhere else — throughout the inner city all day, for example — people experience frequency as maximum wait time, and are not willing to wait long to travel short distances. Even a 15-minute frequency is on the outside of tolerable if you’re just going 3 km or so.
Finally, this graphic Figure 169 , again from HiTrans, which I have annotated, illustrates the issue in Cardiff: A planned oversupply of service at Llandaff and an undersupply on the City and Coryton Lines. Overall, in summary:
- We need less focus on peak time demand at one station
- Look at overall network design and operation throughout day
- Opportunity with higher frequency connected grid to increase off peak demand
(cf experience in Manchester where biggest change post Metrolink was in off-peak demand) - Urban Metro System best practice-minimum service frequency of 4tph (more often 5tph)
Figure 169 Annotated illustration from HiTrans Guidance to exemplify Cardiff “Metro” services
The issue of service frequency is one the WG/TfW and the South Wales Metro will need to address in ongoing work – especially for services in Cardiff (See 15.5 Cardiff, the Cardiff Capital Region and Crossrail).
12.6 Transport modes
I often get dragged into the rail v bus and which is best debate, as if it were an evangelical choice. It really isn’t one can make an informed decision based on an analysis of “the numbers”.
In the following examples, I illustrate five main modes of transport:
- Traditional high-capacity Heavy Rail (HR) seen on most of the UK urban rail network (with vehicles in SE Wales that can typically hold 300-500 people and often more). To note: steel wheel on track is more energy efficient than rubber on road
- Traditional Light Rail (LR) like Metrolink or Tyne and Wear Metro in the UK and now on the South Wales Metro with Tram-train operations (with vehicles that can typically hold 200-400 people if operated in double sets)
- Bus Rapid Transit (BRT) Figure 170 with off vehicle ticketing, segregated operations and a LR type service offer, as is common in many African and South American cities (with vehicles than can typically hold 75-200 people)
- Traditional local and fixed bus routes generally using shared road space (with vehicles than can typically hold 50~75 people)
- Demand Responsive Transit, so bus local routes that change in response to real time demand (e.g. the new Fflecsi service from TfW) (with vehicles that typically hold less than 50 people), DRT can also include local taxi
- Active Travel, so cycling and walking.
Perhaps the primary data set we need to consider at the outset is population and population density – these are material facts when engaged in transport planning. Academic data (examples[35]) suggests that fixed segregated public transit (so HR, LR and BRT), typically needs a minimum population of 200,000, a density 22 people per hectare (pph), and a planning system that encourages employment as well as residential development along transit corridors; especially within 800m of transit stops. These though, are just guidelines and I look to demographics and more detailed local transport demand modelling and benchmarking to inform transport planning and decision making .
In areas with sufficient population density and demand to support fixed services, the choice of Bus, Bus Rapid Transit (BRT), Light Rail (LR), Heavy Rail (HR) is, in general terms, determined by the local demand and long-term revenue and operating profile of the system, as well as the initial capital costs (which are often a barrier for fixed segregated systems – especially rail). The biggest component of operational costs typically relates to numbers of vehicles and staff required to move a fixed number of people.
Figure 170 Segregated BRT in Quito with “stations” & off-vehicle ticketing (credit ?)
As an example, Figure 171 it is operationally more efficient to move 1000~2000 people an hour between two points on segregated infrastructure in 2~ 4 trains (of 300~500 people) or 4~6 Light Rail Vehicles (of 200~400 people) instead of 15~25 buses (of 50~75 people).
Remembering that each bus needs a driver and that a larger number of vehicles has a higher overall operational cost than a smaller number of LRVs; also, if such bus services are not segregated you will not achieve the same reliability or journey times either.
At 100~200 an hour then perhaps 3 or 4 buses works better than one train or LRV, remembering that a frequency of 4 services an hour is generally regarded as the minimum required to deliver a “turn up and go” services able to attract most passengers.
Figure 171 An Illustration of mode applicability Vs demand
Factors to consider when assessing mode options:
- Capital cost (capex), operational cost (opex) and passenger demand
- Segregated operations as much as possible for high demand corridors
- In urban areas “turn up and go” frequencies of at least 4tph
- Maximise utilisation of existing infrastructure to minimise further capital expenditure.
So, broadly, the bigger the local demand (and this is often related to local population density) then fixed segregated rail (HR and LR) and BRT solutions are most efficient, for lower demand then local bus services can be most efficient. For much shorter journeys of up to up to 3km, then Active Travel is best irrespective of population density.
To note: for the South Wales Metro the new Stadler Tram-trains can hold up to approx. 250 people and when operated in double sets 500 people; the Flirt Tri-modes can hold up to approx. 450 people.
For higher demand corridors, segregated BRT can be developed with potentially lower costs than rail if there is sufficient road space able to be easily allocated to fully segregate bus operations. As stated above, segregation allows bus operators to maintain a particular service frequency with less vehicle miles and so less opex.
With the increasing interest in BRT, we also need to avoid the mistake of only providing segregation for bus operations where road space is “easy” to reallocate. However, for efficient and reliable operations the entire route needs segregation. One single pinch point can and will impact the operational efficiency and the reliability and attractiveness of the entire service, as exemplified by the problems experienced by the Delhi BRT scheme[36]; similar issues have impacted BRT systems in Bristol, Boston, Seattle and Portland. The best “local” BRT we can learn from is perhaps the Glider in Belfast[37].
So, we need to be mindful of the “80/20 rule” of a poorly developed BRT system vs a fully segregated LR system, in that the BRT attracts 80% of the capital costs but only 20% of the benefits of a LR solution.
There is a role for segregated bus services and some comprehensive Bus Rapid Transit (BRT) across parts of urban Newport, Swansea and Cardiff where rail capital costs for new build maybe prohibitive and where road space maybe “easier” to allocate to segregate bus operations (E and NE Cardiff for example).
Similarly, segregated bus services can play a role across the urban valleys where redesigned bus networks can be developed to integrate with rail services. Where we already have rail infrastructure in urban areas then enhancing it to enable it to support at least 4tph is the optimal approach Vs trying to replicate or duplicate with more constrained unsegregated bus operations that will deliver fewer benefits. This can result in a subsidised suboptimal bus service competing with a subsidised suboptimal rail service – which pre-Metro is true in some parts of southeast Wales.
Outside the core grid of arterial rail and BRT services, the opportunity is via development of and integration with AT, capillary local bus services and, in areas of low demand (including many rural areas), “demand responsive transit” like Fflecsi.
In contrast to high-capacity PT, trying to move 1000~2000 people an hour in 500~2000 cars are always the least efficient and most environmentally damaging. Autonomous and/or electric vehicles or “pods” can’t change the basic physics and geometry of the question – primarily road space required per passenger and energy costs per passenger. Figure 6. The car industry greenwash trying to persuade us that this is not the case is deeply depressing (See The Climate Emergency and car dependency).
Figure 172 Road space: car V bus V AT (Source Cycling Promotion Fund, Canberra 2013)
12.7 Network legibility & simplicity
One of the legacies of the Welsh Government and Transport for Wales Metro procurement, is the over complicated Train Service Requirement (TSR) that has resulted in services planned from Merthyr, Treherbert and Aberdare to both Cardiff Bay and Central (although not Rhymey as was originally set out by Welsh Government in 2017[38]). This is an unfortunate legacy of my work in Welsh Government in 2015 on the original draft TSR which has been manipulated over time and is now a millstone getting in the way of a more efficient and legible network.
The best Metro networks offer clear legible, high frequency services with good interchange at multiple stations. No-one using London Underground, Manchester Metrolink Figure 173, Newcastle Metro Figure 174, etc expects to be able to get direct services to everywhere from every station. That is just operationally too complex and costly and would increase risk to service reliability. A confusing network actually suppresses demand as passengers cannot easily see how the network functions.
Figure 173 Current Manchester Metrolink network
Figure 174 Newcastle Metro
We need to make some tough decisions to simplify our planned CVL network to create one with fewer higher frequency service groups that enable easy interchange at multiple locations. This will result in an easier to understand, lower cost and more reliable network.
Perhaps the best explanation of the benefits of network legibility and simplicity are set out in the HiTrans Guidance[39] which I have referred to on multiple occasions. The individual services will have to be of sufficient frequency (at least 4 tph) to minimise any interchange penalties (See – Immediate priorities for Cardiff: Crossrail phase 2 to 2028/9 for my suggestions).
This approach will result in a network and services that are:
- Easier to understand
- Easier to plan and operate
- Less prone to perturbation impacts
- And with no change or even an improvement to generalised journey times
Figure 175 From HiTrans Guidance “Network Planning”: basis of high frequency network
Figure 176 From Hi Trans Guidance “Network Planning”
12.8 Post Covid, flexible working & transport demand
The legacy of Covid is clearly impacting future transport planning – especially as we have seen demand for public transport return, but with a very different profile[40].
Furthermore, despite some arguing that we don’t need as much PT in our post Covid world, even with more local and home working, there is still a need for more public transport given the very high levels of car use (~80% commuting mode share).
The adoption of more flexible working presents an opportunity as it appears to be reducing the “peakiness” of public transport demand. Converting the better allocation of work across most employees into a more even demand profile on transport systems, can help address one the biggest issues facing transport operators and governments in supporting and subsidising public transport. That is the stark reality that transport services and infrastructure are typically designed to support demand that is generally in one direction for 2-3 hours, twice a day; often much of the rest of the time trains and buses are moving around with lower loadings. The same applies to the road network with most congestion occurring in the morning and evening peaks.
What we have observed and what we need to encourage, is less demand for travel at pre-Covid peak times and more off-peak weekday trips as well as “leisure” related trips at weekends. This is presenting a challenge to the public transport industry, especially rail, given how much fare revenue was linked to peak time commuting (and so less to “off peak” and weekend leisure trips).
This is forcing many in the PT and especially the rail industry to rethink how it markets and sells its services to the public. This needs to be focussed on those that do not use public transport and less on those that are already users. In this regard surveys of bus or rail users are less useful; we need insight from people in cars and what they need to see in place to persuade them to use PT.
The PT industry would benefit from some insight and expertise from other sectors (e.g., retail) to help address this fundamental question. There is also some data that suggests, that even with better sales & marketing of better PT services, the most effective tool to reduce car use is fiscal and so some degree of Road User Charging (RUC).
Whilst we may develop effective strategies in the next few years, we run the real risk now of exacerbating a challenging problem by responding to the Covid reduction in farebox revenues by making further cuts to subsidies for PT. This will result in a reduction in the number of services and or coverage/frequency thereof. The unvirtuous cycle is a real risk and can only be addressed through strategic response that acknowledges that PT will need more capital and revenue if we are to deliver the kind of mode shift required by our Net Zero targets. The discussion related to RUC cannot be divorced from this stark reality.
One clear opportunity that is presenting itself as result of Covid is perhaps an emerging preference for more organisations to be based in city centres and PT connected paces – and less in car based out of town office parks (less costly to deal with reduced office space in city centres, than office space and the associated car parking space that is costed into the leases of out-of-town office occupiers). So, companies may need less floor space in city centres, but if we can help incentivise further re-locations back to town and city centres and PT connected places, then we deliver both a regeneration and a reduced car dependency benefit. The opportunity to develop a strategic TOD response is very real (See Why we need Transit Oriented Development (TOD)).
12.9 Fares and subsidies
Finally in this section I want to touch briefly on the complex issues of fares and subsidies. We often hear that we should make public transport free. Well, this is not as straightforward as it sounds. In the UK it is also a challenge (less so in Europe) given that for 50 years the burden of operating costs has increasingly fallen more on the passenger and less on the taxpayer. This for me, reflects the long-term systemic undervaluation of the importance of high quality, accessible public transport in the UK. The more generally held European view of public transport as essential economic infrastructure is also manifest in the availability and range of services available to passengers – and capacity. This more enlightened view is not shared by Westminster.
So, in principle I favour the idea of free public transport given all the wider external benefits, which are many. So more and free public transport is a “no-brainer”?
Well, maybe not; there are challenges and choices. Public Transport is not free to operate, it has a cost, and for most bus and train services, farebox revenue has to be augmented with public subsidies (which given the above benefits is reasonable). However, there are also always limits on how much money can be allocated to subsidise public transport. And remember dropping fares can attract more demand, and so we also need to be able to provide more capacity to carry it.
More relevant is that given our Net Zero targets we need 40% more PT capacity by 2030 and at least a doubling again by 2040. There are clearly very significant capital costs to implementing the additional infrastructure required, but perhaps more challenging is finding the revenue to support the increased operational costs of running all these extra services. The additional incremental operational cost of introducing that additional capacity cannot be ignored.
Let’s take a simple example. Imagine a simple bus network that costs £10M each year to run but needs £5M in public subsidy to add to the £5M ticket revenue to cover its costs. Let’s assume it is pretty much full all the time (so no spare capacity) and we know there is local latent demand for more services.
If we have an extra £5M subsidy, do we:
“A” – Make the existing bus service free?
OR
“B” – Keep the price/fare the same but double the capacity by funding a doubling of the frequency and/or adding a new route, so doubling the number of passengers?
Both the above examples result in a total public subsidy of £10M. However, “A” now has no ticket revenue, so is fully subsidised and carries no more people, so the subsidy per passenger has doubled.
“B” also receives £10M in subsidy, but also attracts another £5M in additional ticket revenue (so now £10M farebox in total) from the extra passengers attracted to the additional services/capacity.
Whilst “B” now costs £20M to operate, it carries twice as many people as “A”, so helping deliver our Net Zero mode shift targets. This additional capacity will also require additional staff providing a “job creating” economic benefit as well as more of the wider benefits I set out above. More challenging perhaps, to double the capacity of “A” so that it carries as many passengers as “B”, would take a public subsidy of £20M (Vs just £10M for “B”)
However, I know in the real-world buses are not full all the time and lower/free fares will attract more PAX, and doubling capacity will not necessarily double passenger numbers. This is a simple example to exemplify the stark choice. With limited resource, do we make the current services and capacity thereof free, or do we invest to increase the capacity and reach of public transport?
The former may present opportunities for political sound bites, but it is the latter that delivers on the wider benefits.
I support lower and more equitable fares, but not free, primarily for the reasons above. Our priority has to be more capacity and integration across rail and bus, with a common fare structure via a low capped multi modal PAYG (“pay as you go”) system.
Furthermore, in broad terms, making anything free tends to reduce its “value” in the mind of the user of such services and sometimes generates unintended consequences.
In bus terms we can see the unintended consequences of free bus fares for older people. Many bus companies have optimised their networks to carry more concessionary fares which they can claim back, and so perhaps are less focused on more economically valuable services that are more farebox dependant.
Similarly, I also think the calls for free parking, even for hospital staff, should be resisted as it just encourages more car dependency with all the negative wider impacts alluded to above; much better use of public funds is to enable more bus services.
So, I favour re-allocating some of the subsidy for free bus travel enjoyed by older people (and I am 61 now) to young people, for whom travel costs can often make up a very high proportion of their disposable income. Illustratively for short trips, perhaps a flat £1 charge for older people and young people and £2 for everyone else, with a capped daily amount for multiple trips (Capped PAYG)?
Given the clear benefits to health budgets (both short term through lower RTAs and long-term improved health from more AT), perhaps Government (inc. WG) need to allocate some of those savings from the Health Department to the Transport Department.
Also, worth noting some recent research which suggest in some circumstances that making PT free does necessarily reduce car use, and that in some circumstances the resulting mode shift is from walking and cycling to PT with little impact on car use[41].
This is why I favour a multi-facetted approach. So, in addition to any reduction in fares for PT use, we also need a complementary reduction in the car use discount (See The Climate Emergency and car dependency) which will help provide the resources needed for the additional PT capacity we also need.
More generally, as part of the serious fiscal overhaul we need[42], more tax should be applied to things we use and buy (and in so doing present consumer prices that properly reflect any negative externalities).
Another consideration that directly impacts how many services we can operate is the unit cost of operating such services and the overall subsidy requirement. This will particularly affect the new Metro Tram-train services where we need to operate higher frequencies to attract passengers. Most LR systems in the UK, as stated earlier, operate with very different T&Cs to the National Heavy Rail network. Trams don’t have guards and operate with Driver Only Operation (DOO). Having extra staff on such vehicles adds to unit costs and can make the subsidy required to operate more services a barrier. If the unit costs are minimised, then such services (as is the case in Manchester) can operate without any further subsidy as the farebox covers the operational cost. I am not sure that will be the case under current plans for the South Wales Metro. This is something we will need to revisit.
Much to ponder…
References
[1] My thanks for help and support over the last 14 years goes to (in no particular order):
Stuart Cole, Simon Gale, Roger Waters, Andrew Gregory, Paul Carter, Jason Dixon, Clare Cameron, Clive Campbell, John Duddridge, Gareth Newall, Jonathan Day, Ken Poole, Simon Nichols, Emma Reed, Sheila Davies, Paul Matthews, Paul Orders, Richard Crook, Kellie Beirne, Matt Price, Clare Moggridge, Neil Hanratty, Dewi Rowlands, Alison Thomas, Helen Bowkett, James Ardern, Dave Thomas, Andrew Jones, Luke Albanese, Roddy Beynon, David McCallum (who now has a lead role at TfW), Stephen Lawrence, James Brown, Chris Sutton, Robert Chapman, Ben Pritchard, Daniel McCool Claire Falkiner, Andrew Jenkins, Gavin Lewis and the many others who have helped me on my transport planning journey…
[2] Including at Cardiff University Kevin Morgan, Dimitris Potoglou, Gill Bristow, Brian Webb, Neil Harris, Justin Spinney, Francesca Sartorio, Oleg Golubchikov, Calvin Jones, Andrew Potter, Calvin Jones, Adrian Healy and many others
[3] TfW and people like Geoff Ogden, Lee Robinson, Catriona Lloyd, David McCallum (who keeps cropping up in this book), Rob Jones, Ben George, Ruth Wojtan, Paul Chase, Tom Alcock, Amy Nichols, Huw Morgan, Ian Cater, Tracey Kearns, Gethin George, Gareth Potter, Matt Gilbert, Alison Walker, Mark Casey, Andrew Sherrington(now back in the bus industry), Andy Holder, Steve Whitely, Steve Ward, Andrew Gainsbury, and many others…
[4] Jarrett Walker, 2024, “Human Transit” The professional blog of public transit consultant Jarrett Walker.
[5] Victoria Transport Planning Institute, Victoria Transport Institute – Main Page (vtpi.org)
[6] Robert Cervero, Berkeley Institute of Transport Studies Robert Cervero | Institute of Transportation Studies
[7] Jarrett Walker, Urban Transit, Human Transit — The professional blog of public transit consultant Jarrett Walker.
[8] HiTrans European Commission, 2005, Development of Principles and Strategies for Introducing High Quality Public Transport in Medium Size Cities and Urban Regions | TRIMIS (europa.eu)
1- Public transport & land use planning
2 – Public transport – planning the networks
3 – Public transport & urban design
4 – Public transport – mode options & technical solutions
5 – Public transport – citizens’ requirements.
[9] Mark Barry, Cardiff Capital Region 2021, “Rail Passenger Vision” CCR-passenger-rail-vision-english.pdf
[10] Blogsite of Jarrett Walker, “Human Transit”: The professional blog of public transit consultant Jarrett Walker.
Basics: The Ridership – Coverage Tradeoff — Human Transit
Chicago: The Ridership-Equity Tradeoff, a Video — Human Transit
[11] Welsh Government, 2015, Well Being of Future Generations, Well-being of Future Generations (Wales) Act 2015 – The Future Generations Commissioner for Wales
[12] Todd Litman, VTPI 2021, “The Business Case for Post Covid Public Transport” bcpct.pdf (vtpi.org)
[13] Todd Litman, VTPI 2021, “Evaluating Transport Planning Equity” Evaluating Transportation Equity (vtpi.org)
[14] WelTAG, Welsh transport appraisal guidance (WelTAG) | GOV.WALES
[15] Matt Lowrie, Greater Auckland, 2020 Is transport modelling junk science? – Greater Auckland
[16] David Boyce, Huw Williams, EE Elgar, 2015, “Forecasting Urban Travel”
[17] Welsh Government, 2021 Llwybr Newydd: the Wales transport strategy 2021 | GOV.WALES
[18] Welsh Government, 2021, Net Zero Wales | GOV.WALES
Policy 32 – Increase trip mode share of public transport from a current estimated proportion of 5% to 7% by 2030 (a 40% increase) and 13% by 2040
Policy 31 ‒ Increase trip mode share of active travel from a current estimated proportion of 27% to 33% by 2030 and at least 35% by 2040
Infers a reduction in car mode share from 68% to 60% by 2030 and down to 52% by 2040 and nearly three times as much PT use by 2040
[19] DfT, 2015, Values of travel time savings and reliability: final reports – GOV.UK (www.gov.uk)
[20] Arup for DfT, 2015, Provision of market research for value of travel time savings and reliability Report (publishing.service.gov.uk)
[21] Max Planck – Biographical – NobelPrize.org
[22] The Nobel Prize in Physics 1921 – NobelPrize.org
[23] Photoelectric Effect – an overview | ScienceDirect Topics
[24] Values of travel time savings and reliability: final reports – GOV.UK (www.gov.uk)
[25] Senedd, Explanatory Memorandum to the Restricted Roads (20 mph Speed Limit) (Wales) Order 2022 EM template for sub leg (senedd.wales)
[26] Science Direct, Black Body Radiation, Black Body Radiation – an overview | ScienceDirect Topics
[27] ORR Notes on 1998 Competition Act, Competition Act 1998 | Office of Rail and Road (orr.gov.uk)
UK Gov 2008, Bus industry: competition law following the Local Transport Act 2008 – GOV.UK (www.gov.uk)
[28] HiTrans European Commission, 2005, Guidance 2 – Public transport – planning the networks
[29] Transport For Wales, “Metro”, Metro | Transport for Wales (tfw.wales)
Mark Barry blog, “Metro Update Feb 2022” Wales’s Metros – Update Feb 2022
[30] Jarrett Walker, Human Transit, 2011, How frequent is freedom? — Human Transit
Greg Jordan-Detamore, Blog 2016, How frequently does transit need to run? It depends on distance (gregjd.com)
Jarrett Walker, Human Transit The Case for Frequency Mapping — Human Transit
[31] Erik B Lunk, N. Fearnley, J. Aarhaug; Research in Transport Economics, 2021, “ Public transport competitiveness vs. the car: Impact of relative journey time and service attributes – ScienceDirect
[32] TRL, The Demand for Public Transport: A practical Guide, 2004 The Demand for Public Transport
[33] Todd Litman, Victoria Transport Planning Institute 2023 Transportation Elasticities (vtpi.org)
[34] Jarrett Walker, Human Transit, 2010, “Australia: Pitfalls of Metro Envy”
[35] David Flannery, Renee Duarte, Barbara Norman, Tayanah O’Donnell, Hamish Sinclair and Will Steffen; University of Canberra; Light rail transit and residential density in mid-size cities Working Paper 5 June 2015
(PDF) Light rail transit and residential density in mid-sized cities (researchgate.net)
Cameron Gordon, University of Canberra, 2011, Planning for Structural transit in low density environments: The case of Canberra, Australia;
(PDF) Planning for structural transit in low density environments: The case of Canberra, Australia (researchgate.net)
Robert Cervero and Erick Guerra, Institute of Transportation Studies, University of California, Berkeley, 2011; Urban Densities and Transit: A Multi-dimensional Perspective qt3mb598qr.pdf (escholarship.org)
[36] Tanvi Misra, Bloomberg, 2016 Why Bus Rapid Transit Failed in Delhi – Bloomberg
[37] Northern Ireland, Department for Infrastructure Belfast Rapid Transit – Glider Introduction
[38] Welsh Government, 2017, “Policy-priorities-for-wales-and-borders-rail-services-and-Metro-operator-and-development-partner-procurement.pdf”
[39] John D. Nelson (University of Newcastle) Corinne Mulley (University of Newcastle) Göran Tegnér (Transek AB) Gunnar Lind (Stratega AB) Truls Lange (Civitas Consultants) Civitas 2005, HiTrans Best Practice – Network Planning Guidance
[40] ORR 2023, Passenger rail usage | ORR Data Portal
[41] Nicole Kobie, Wired, 2022 “The Case for Making Public Transit Free Everywhere”
Andersson, Björklund, Warner, Lättman, Adell; Transportation Research Part F: Traffic Psychology and Behaviour, 2023; The complexity of changes in modal choice: A quasi-experimental study – ScienceDirect
[42] The Environment, Tax and Wales – Mark Barry (swalesMetroprof.blog)