To get our cities moving again, we need a new kind of urban professional

In this extract from my new book The 30-Minute City,  I argue that in designing our cites, we need ‘Urban Operations’ experts who can straddle the realms of both strategy and tactics. Reprinted from Foreground

Access is the driving force behind how cities were built – which is to say, cities developed with the goal of making it as easy as possible for people to reach the opportunities and activities contained within them. In the contemporary city, though, the professionals tasked with designing and developing our cities for access can often seem to be working at cross-purposes.

Our engineers are trained in engineering school to ‘do it right.’ They are trained intensively in calculations to make sure the math works out. This is very important: structural engineers do not want to misplace a negative sign or they would build the bridge upside down. In contrast, our planners retort to the engineers ‘do the right thing.’ What are the right values? And that’s really important, too. Meanwhile, our public citizens say: ‘do the right thing right’, synthesising this apparent conflict.

30-minute-city
The 30-minute City: Designing for Access, David Levinson

In designing and managing our cities for access, we need to think about both strategy and tactics. We need to think about ideas and implementation. For instance, at train stations with entrances on only one end of the platform, the objective of enabling people to leave the station is supported, but not the broader objective of enabling them to reach their destinations in the least amount of time. Traffic signals presently are timed to minimise delay for vehicles, but not for people, and fail to count vehicle occupancy (buses wait in the same traffic as cars) or pedestrians.

“Traffic signals presently are timed to minimise delay for vehicles, but not for people” – David Levinson @trnsprtst

 

A Nihilistic Theory

I’m going to introduce a ‘nihilistic’ theory of transport and land use: everything is ‘pointless.’

Transit facilities are pointless. A station is not a point, it is a place.

Junctions are pointless. A junction, or intersection, is not a point, it’s a space. It has conflict points, which are also spaces, but it takes time to traverse, and those traversing it take up space.

Cities, too, are pointless, and yet planners often abstract away important details – as in the Greater Sydney Commission’s Metropolis of Three Cities plan, which, like so many regional plans, has dots on maps to represent whole communities.

Everyone working in the urban sphere should recognise this ‘pointlessness.’

Just as small spatial relations matters, so too does time. Do small amounts of time savings matter? Yes! Absolutely!

A traffic engineer proposes a change that will save somebody five seconds, and someone inevitably retorts that nobody cares about five seconds. But we can never get to larger time savings (or accessibility gains) when we’re always talking about how unimportant the small changes are. There is no way to save 15 seconds if you don’t save five seconds. There is no way to save 30 seconds unless you save 15, or one minute unless you save 30 seconds, or five minutes unless you save one minute.

Trips comprise many time elements, and use many bits of the transport network, and we are not going to save time all at the same place or with the same project or process. So the better practice is to take the gains that are possible, as they will accumulate over time. Saving time, or increasing speed, increases the area that can be covered in the same amount of time, and since accessible area increases with the square of the radius, time savings have disproportional effects on accessibility.

This argument applies to all modes. The traffic signal engineers use it to justify their signal timings for automobiles. The potential flaw here is not in saving time, but in doing so at the expense of pedestrians and the neighbourhood at large.

There is the argument that time, unlike money, cannot be ‘saved’, as there is no way to store it. And of course there is an element of truth there. But I would argue that time can be used for things that are valued more highly than standing at an intersection waiting to cross – which is to say, anything else. The time not spent waiting at the intersection might be spent in a more pleasant environment, or walking or riding farther to a slightly better or higher paying job, or a shop with somewhat better goods, or from a slightly better or less expensive home. These are the trade-offs people make all the time, and by increasing the area that can be traversed in a given amount of time, we increase opportunity and choice.

A profession that is interdisciplinary in real time – or, doing the right thing right

To do the right thing right, we want to forge a new profession that is interdisciplinary in real time. Planners create long-term plans covering large areas – they, at least in theory, aim to optimise for all of society. Analysts develop policies over large areas, which have a shorter-term time horizon, and also should at least consider all of society. But the local-looking professions – engineers, architects, urban designers, and technicians of various kinds – whether they are involved in building for the long-term or managing and operating the system in the short-term, by definition optimise locally, for the site, rather than the city. How the site interacts with the city is neglected.

We need a profession not of more urban planners, nor of more transport engineers, but urban operators – people engaged in today’s city, not tomorrow’s, but who can optimise for the system as a whole (that is, by thinking about accessibility) and not just their small piece of it.

The world is changing ever-faster. Yet strangely, today’s professionals undertake and celebrate very long-term plans where they acknowledge the existence of a problem (i.e. congestion), and technology (i.e. autonomous vehicles), but don’t acknowledge that anything changes.

Instead, we should forge new urban operators as a strong alloy of planning, engineering, economics, and design. Urban operators take ideas in real time and solve today’s problems with resources on-hand, rather than solving imagined problems that bring distant dangers near. We have enough problems today. We also have solutions available to us today, and we don’t implement them. And yet people are employed to work on 40-year plans.

“We need a profession not of more urban planners, nor of more transport engineers, but urban operators – people engaged in today’s city, not tomorrow’s, but who can optimise for the city as a whole” – David Levinson @trnsprtst

Today’s disciplines are excellent for admiring and nurturing today’s problems, but not nearly so adept at solving them. Engineers and planners are so focused on the long term, their jobs effectively require them to build it and then abandon it. Operating and maintaining the system is someone else’s responsibility. Once they have made their design they hand it over to a contractor for construction, who then hands it over to the client.

And then we have people who are making microscopic decisions without thinking about the big picture. Where do you put the bus stop relative to the train station? This affects accessibility, but the decision is made based on what is convenient for the bus operator rather than passengers, or worse, to minimise delay for cars.

As Bill Garrison argued, we want people who can bridge the hard and the soft – the hardware engineering of infrastructure and vehicles and the software of management, control, and financial systems.

Bridging or merging the soft and the hard would vastly improve policy and policy-making processes. We should be able to simultaneously think of engineering and policy, not be restricted to engineering or policy. Those of us in the transport field should identify as transportists – not transport engineers or transport planners or transport economists. The problem must come before the mechanism of solution.

We want people who can bridge the site and the city. People who think about the position of a train platform in the greater context of the metropolitan area, so that people living on the south side of the platform can easily reach it, rather than semi-circumnavigating the train station to its only entrance on the north.

We want a fusion of planners and engineers who would focus on the ends not on the means, who can think in multiple scales and multiple time horizons.

The goal of the 30-minute city aligns with travel time budgets and human behaviour. We know that, historically, land developers and the railway builders were keen on the idea of a feasible commute, and they were keen on this idea when they deployed tram and train networks and concomitantly subdivided large tracts into lots and built homes that were within a 30-minute commute of the central city.

Lower case ‘d’ design

Architects are famous for BIG design ideas. But cities are not amenable to big designs any more. They grow (and should grow) incrementally, not comprehensively. So instead let’s talk about what I will call “lower case ‘d’ design,” the humble design decisions about where to put bus stops relative to station entrances, and how to time traffic signals. These are small urban design decisions that don’t get sufficient attention.

There are many things that we can do that involve rethinking the details – like adding train station gates to both ends of platforms to expand catchment areas, and thus patronage. Details like stop spacing and location, practices like all-door boarding, payment before boarding, optimising timetables and frequency, may just squeeze a few seconds per stop or minutes per route out of the existing configuration, but collectively they greatly expand people’s accessibility.

More strategically, this requires thinking about transport and land use balance. Offsetting today’s imbalance can give us growth without additional travel or commuting-related congestion. To achieve a 30-minute city, cities need to put new jobs in housing-rich areas and new housing in job-rich areas systematically as a way of growing. This contrasts with local government’s desire to focus employment in the central city, and developers who will tend to put more housing in the outer suburbs where there are many fewer jobs.

And we need to design for the cities we want, not ‘predict and provide’ for the city we forecast. Our future cities cannot be delivered by the same disciplinary thinking that created the cities we have.

This is an abridged extract taken from David Levinson’s book The 30-Minute City: Designing for Access, available here in PDF format and here in print.

Levinson joined the School of Civil Engineering at the University of Sydney in 2017 as Foundation Professor in Transport Engineering. He conducts research on accessibility, transport economics, transport network evolution, and transport and land use interaction.

Moving Forward Framework (take 2)

The previous version of this post was eaten by WordPress.

Moving Forward Framework: For the People
Moving Forward Framework: For the People

A reader writes: “The U.S. House [Transportation and Infrastructure Committee] came out with its pre-election transportation policy: The Moving Forward Framework, and access measures made it into what is otherwise a high-level policy document (with no hint about how they plan to pay for their wishlists.)”

On Access to Jobs:

It’s infrastructure investment that is smarter, safer, and made to last – with a framework that:

  • Ensures a transportation system that is green, affordable, reliable, efficient and provides access to jobs

and

Modernizes Project Planning – Requires States and MPOs to prioritize transportation access and to consider during the planning process all system users, job access, connections to housing, and creation of transportation options in underserved communities.

On Fix-It-First

Revamps Existing Formula Programs

Amends core highway formula programs to prioritize investments and improve program implementation:

Fix it First – Prioritizes maintaining and improving existing infrastructure and bringing it up to a state of good repair, including roads, bridges, tunnels, and ferry systems.

On Road Pricing

Tackles Congestion Equitably – Institutes tighter standards around tolling and congestion pricing.

Tests the Viability of New Transportation User Fees

Transforms revenue collection and distribution by authorizing a multi-year national pilot program to test revenue collection to ensure the future viability and equity of surface transportation user fees, including a vehicle-miles travelled fee.

 

It’s almost as if it were written by a reader of this blog.

The 30-Minute City: Designing for Access

The 30-Minute City by David M. Levinson
The 30-Minute City by David M. Levinson

Now available for purchase: The 30-Minute City: Designing for Access.

The book reads fast, with just over 20,000 words, and contains 50 images and 6 tables.

About

This book describes how to implement The 30-Minute City.  The first part of the book explains accessibility. We next consider access through history (chapter 2). Access is the driving force behind how cities were built. Its use today is described when looking at access and the Greater Sydney Commission’s plan for Sydney.

We then examine short-run fixes: things that can be done instantaneously, or nearly so, at low budget to restore access for people, which include retiming traffic signals (chapter 3) and deploying bike sharing (chapter 5) supported by protected bike lane networks (chapter 4), as well public transport timetables (chapter 6).

We explore medium-run fixes that include implementing rapid bus networks (chapter 7) and configuring how people get to train stations by foot and on bus (chapter 8).

We turn to longer-run fixes. These are as much policy changes as large investments, and include job/worker balance (chapter 10) and network restructuring (chapter 9) as well as urban restoration (chapter 11), suburban retrofit (chapter 12), and greenfield development (chapter 13).

We conclude with thoughts about the ‘pointlessness’ of cities and how to restructure practice (chapter 14).

The appendices provide detail on access measurement (Appendix A), the idea of accessibility loss (B), valuation (C), the rationale for the 30-minute threshold (D), and reliability (E). It concludes with what should we research (F).

Table of Contents

  • Preface
  • 1  Introduction 15
  • 2  The 30-Minute City: Then and Now 19
  • 3  Traffic Signals 25
  • 4  On the Four Paths 29
  • 5  Bikesharing 35
  • 6  Timetable 37
  • 7  Rapid Bus 39
  • 8  Interface 45
  • 9  Gradial: Or the Unreasonable Network 51
  • 10  Job-Worker Balance 55
  • 11  Urban Restoration 59
  • 12  Retrofit 69
  • 13  Greenfields and Brownfields 75
  • 14  A New Profession: Urban Operations 81

Appendices

  • A  Theory 89
  • B  Accessibility Loss 93
  • C  Access Explains Everything 95
  • D  Why 30 Minutes? 97
  • E  Reliability 99
  • F  Research Agenda 101

FEATURES

  • 114 pages.
  • 50 Mostly Color Images.
  • ISBN: 9781714193660 (Blurb Paperback)
  • ISBN: 9781714193486 (Ingram Trade Paperback)
  • ISBN: 9781714193561 (Ingram Hardcover)
  • ISBN-10:  (Amazon)
  • ISBN-13:  (Amazon)
  • Publisher: Network Design Lab

PURCHASE

Commute Mode Share and Access to Jobs across US Metropolitan Areas

Recently published:

How much of the variation in transit mode share is attributable to accessibility is not well understood, despite its significant policy implications. It is hypothesized that better transit accessibility leads to higher transit mode share. This paper explains block-group level transit mode share using transit accessibility in a logistic model for 48 major US metropolitan areas. Transit accessibility alone explains much of the variation in transit mode share for all 48 regions despite their geographical differences (adjusted R2 0.61, potential accessibility); models for individual cities have stable and interpretable parameters for transit accessibility. The models better explain mode share in cities with higher person weighted transit accessibility and larger populations; an adjusted R2 of 0.76 is achieved for New York City with transit accessibility as the only explanatory variable. Additional automobile accessibility and income variables modestly improve model fit. Time-decay functions fitted to accessibility measures better explain mode choice than the isochrone accessibility, and suggest the catchment area affecting transit mode choice to be within 35 minutes. This work contributes to the understanding of transit mode share by solidifying its link with accessibility, which is determined by the structure of the transport network and land development.

Boston30

How Transit Scaling Shapes Cities

Recently published:

Transit accessibility to jobs (the ease of reaching work opportunities with public transport) affects both residential location and commute mode choice, resulting in gradations of residential land use intensity and transit (public transport) patronage. We propose a scaling model explaining much of the variation in transit use (transit commuters per km2) and residential land use intensity with transit accessibility. We find locations with high transit accessibility consistently have more riders and higher residential density; transit systems that provide greater accessibility and with a larger base for patronage have proportionally more ridership increase per unit of accessibility. All 48 metropolitan statistical areas (MSAs) in our sample have a scaling factor less than 1, so a 1% increase in access to jobs produces less than 1% increase in transit riders; the largest cities have higher scaling factors than smaller cities, indicating returns to scale. The models, derived from a new database of transit accessibility measured for every minute of the peak period over 11 million US census-blocks, and estimated for 48 major cities (MSAs) across the United States, find that jobs within 45 minutes most affect transit rider density. The findings support that transit investment should focus on mature, well-developed regions.

Scaling Coefficients for Transit Commuter and Working Population Density (dot sizes corresponds to residential density); Between-cities scaling (pooling 48 cities) shown with the solid red dot; All cities above the red diagonal line
Scaling Coefficients for Transit Commuter and Working Population Density (dot sizes corresponds to residential density); Between-cities scaling (pooling 48 cities) shown with the solid red dot; All cities above the red diagonal line

Transport Accessibility  Manual Working Group

The Committee of the Transport Accessibility Manual will meet at the Transportation Research Board Annual Meeting in Washington DC in January:

final_cbsa_35620Transport Accessibility Manual Working Group (SAM20-0007 AP050)
Tuesday, Jan 14, 2020  8:00AM  9:45AM (US Eastern Standard Time)

We will be discussing the first (preliminary) draft of the document, which will be distributed to mailing list members before the meeting. Contact me if you would like to be added to the mailing list.

Gradial: Or the Unreasonable Network

The reasonable network adapts itself to the world; the unreasonable one persists in trying to adapt the world to itself. Therefore all progress depends on the unreasonable network.1

The physical location of network infrastructure is one of the most permanent decisions cities make. The Cardo Maximus in the old city of Jerusalem is still a main north-south shopping street, constructed when Emporer Hadrian rebuilt the city in the 130s CE.

The 30-Minute City by David M. Levinson
The 30-Minute City by David M. Levinson 

A street right-of-way, once created is seldom destroyed. A segment of that infrastructure is designed to be optimal at a moment of time, with a particular land use (either the realized development of today or an imagined place of tomorrow), enmeshed within a particular network context of all the other nodes and links, compatible with a particular technology. That it functions at all when land use, networks, and technologies change radically, as they do over centuries, is testament to the general flexibility inherent in networks. But the implication is that if it is optimal for the world in which it was designed, it is unlikely to be optimal as that world changes.

Some adaptations do occur. Streets designed for horses were adapted for streetcars (trams) and bicycles and cars and buses and pedestrians.

Still, it may be the best that can be done. Embedded infrastructure, the dictionary example of sunk costs,2 cannot adapt much to the world around them. Instead we expect the world to adapt to the infrastructure.

Following Shaw, we might say such infrastructures are `unreasonable’, in that they cannot be reasoned with.

Many, if not most, planned cities have been laid out with a network of streets “with the sombre sadness of right-angles,” as Jules Verne, quoting Victor Hugo, described the American grid in Salt Lake City, of streets at 90-degree angles to each other, in his classic road trip story: Around the World in 80 Days. Street grids don’t plan themselves, so while all street grids were planned, not all plans result in street grids.

Organically developed3 cities are often more naturalistic, radial cities, with streets feeding the city from the hinterlands, allowing more than 4-directions of entry. All roads lead to Rome, as the saying goes. The Romans themselves were a bit adverse to this organic radial system once they got their own growth machine going, laying out encampments and new settlements on the grid system. The radial system leading to and from the town would bend once it reached the town gates. But as cities themselves were generally not conceived of as whole, but rather themselves emerged, often as conurbations of smaller settlements, towns, and villages, there are often radial webs centered on town A overlapping radial webs centered on town B. Rome was famously built on seven hills, which can be read as meaning Rome is a conurbation of seven earlier villages. (See Elements of Access, Chapter 3.3)

Each of these networks typologies has its advantages and disadvantages.

DCMetro
Washington DC Metro. The center is a space, not a point. A `triangle’ is formed by L’Enfant Plaza (Yellow/Green with Orange/Blue/Silver), Metro Center (Red with Orange/Blue/Silver), and Gallery Place (Red with Yellow/Green)

 

We observe that radial networks are optimal to maximize access for many-to-one types of movements (suburbs to central city). So rail transit networks, which serve the high loads demanded by, and making possible, high density city centers tend toward being radial. But when they are large they are usually not so radial that all the branches meet at one junction. From a network design perspective, intersecting more than two lines at a station can lead to other types of conflicts, and many systems are designed with triangular center to avoid overloading a single transfer station. Washington DC’s largely radial Metrorail system, shown in  the first figure, illustrates this design. Cities are spaces, not points.

In contrast, the 90-degree grid is reasonably well-suited to maximize access for scattered trips, what network analysts would call a many-to-many pattern. We see this especially in dispersed point-to-point (suburb to suburb, within city to within city) flows that are enabled by and reinforce the grid. This is the network for the automobile. The Los Angeles freeway grid, the famous Milton Keynes arterial grid, and numerous other  late twentieth century cities have been designed in a grid-like way (though not so orthogonal that Victor Hugo would object). Even though the topology is not as efficient from a distance perspective as say a 60-degree mesh, by remaining out of the city core it can keep speeds higher.

But in response to the landscape that emerged with the automobile, transit planners like Jarrett Walker (2012) have called for more grid-like transit networks, so people can move, via public transport, from suburb to suburb without going through the city centre. This is relatively easy to reconfigure for buses, the very definition of  mobile capital, while very difficult for the more capital intensive rail networks with their physically embedded infrastructure.

Still, core radial lines will always be the backbone of transit systems so long as at least one important center justifies a disproportionate amount of service.

So how can we grid the radial, or square the circle, so to speak?

A better network topology might be the 60-degree, hexagonal pattern. (Ben Joseph 2000) But remaking street grids for existing cities is tough-going, as property rights are well established, and requires efforts like those of Haussmann in 19th century Paris. (Willms 1997).

daganzo
Possible system layouts: (a) hub-and-spoke; (b) grid; (c) hybrid. Source: Figure 1 in Daganzo (2010)

Instead, we have overlapping network topologies, ideally which are grade-separated in some fashion, so trains are radial and don’t intersect streets or motorways, and bus services can be more grid-like, and rapid or express bus networks serve the market niche in-between.

Thus the original street level networks are still topologically grids, but the services running on that grid, while still largely parallel and perpendicular, are compressed near the center, so the bus lines, for instance, bend towards the center, as illustrated in the second figure. The regulatory layer of through streets for automobiles may be constructed to defer to the orientation of bus services.

There are no optimal network configurations independent of the enveloping land use pattern or the technological regime. Similarly there are no optimal land use allocations independent of the network pattern or technology. Finally, there is no optimal mode independent of the land use or network. All three of these systems are interlocking. Moving one requires adapting the others.

The unreasonable network forces the land use pattern to adapt to it, such that relocating network elements is more costly than keeping them in place. Similarly, in many ways the network, designed for a given technology, is very hard to adapt to a different technology. That doesn’t stop people and cities from trying, the misfit we see with the automobile in the urban core is the product of failing to acknowledge this unreasonableness. But as the number of European cities restricting cars in the city center are showing, the unreasonable network wins out over technology too.

The Grid/Radial Gradial network is also Gradual. These systems seldom change all-at-once, instead they gradually evolve over decades, centuries, and millenia.


Notes:

1. This is an adaptation of a famous George Bernard Shaw quote.

The reasonable man adapts himself to the world; the  unreasonable one persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man.

2. The economist’s adage that “sunk costs are sunk” means that once something has been built, and that money spent, it no longer factors into benefit-cost analysis about how prospective decisions should be made, except to the extent it changes the costs of various options. Logically, you shouldn’t go to a concert just because you bought tickets if you don’t want to go, though if you are considering going to a concert or a bookstore after you bought the tickets, you don’t need to account for paying for the tickets again. You might also consider the `opportunity cost’ of going as the loss from not scalping the tickets. You shouldn’t throw good money after bad. But the sunk infrastructure cannot be unbuilt.

3. Organic development is often largely systematically unplanned, though obviously some degree of planning often goes into laying out a street, even if it is disjoint from any other decisions. When we think of `planning,’ we are generally referring to longer-term more strategic type spatial plans, that consider interactions between prospective decisions, rather than short-term tactical plans that optimize a single decision alone decontextualized from the rest of the city.

Access Across Australia Interview

I was interviewed about our Access Across Australia report by Jane Slack-Smith. It was a really good interview and got into the connections between access and real estate prices. The interview is posted to Facebook, for those of you who use the platform:

Access across Australia: mapping 30-minute cities, how do our capitals compare?

Reprinted from The Conversation.

Accessibility – the ease of reaching valued opportunities such as jobs, workers and shops – is the whole reason cities exist. There is no reason to locate anywhere but to be near things, far from things, or to possess things. Access measures this.

Locations with better accessibility to urban opportunities generally have higher development density and more expensive real estate. This is because places with higher accessibility are more productive, so their workers earn higher wages. And modes of transport that reach more opportunities – that is, provide access to places where people work, live, shop, and more – tend to have higher market share.

Our new report, Access Across Australia, for the first time generates a set of consistent maps and graphs of 30-minute access to jobs and workers by each transport mode for each of the eight capital cities. This covers around 70% of the nation’s resident workers and employment opportunities.

The full report compares 10-minute to 60-minute accessibility to both employment locations and to workers’ homes by four modes of transport – car, public transport, walking, and cycling – for each city. It also reports the overall job-worker balance, comparing how many workplaces can be reached to how many competing workers want to reach those same workplaces.

The accessibility measures take into account the effects on travel times of traffic congestion and the walking and transfer elements of the public transport mode.

Accessibility captures the combined effect of land use and transport infrastructure. The faster and more direct the network, the higher the access. The more opportunities (people and places) that can be reached, the higher the accessibility.

This value varies across and between regions. For this article, we show this in maps for Sydney – the full report has maps for all four transport modes, for both jobs and labour (resident workers), for all eight cities. In the table, city-level accessibility numbers are reported as a metropolitan average, weighted by the number of people who experience that accessibility (population-weighted accessibility), to best represent the experience of the working population.

Population-weighted 30-minute accessibility to jobs; cities ranked by the size of employment opportunities. Hao Wu and David Levinson

The rankings in the table are discussed below for each mode.

Cars

Cars have higher accessibility than public transport, walking, or cycling. Perth has the greatest number of jobs and workers reachable by car within 30 minutes.

At time thresholds of 40 minutes and longer, residents of Sydney and Melbourne have higher accessibility than other cities. During the morning peak period, Melbourne has moderately better car accessibility than Sydney, despite Sydney being larger and having more opportunities overall. This indicates that roads in Melbourne are faster than those in Sydney.

30-minute job accessibility by car in Sydney. Hao Wu and David Levinson

 

Public transport

Public transport accessibility incorporates time to reach transit stops and station on foot, and equals the minimum of walking and transit times between an origin and destination. It remains at a significant disadvantage compared to car travel, reaching between 12% and 18% of the urban opportunities accessible by car under a 30-minute threshold.

Public transport accessibility tends to be high in city centres and low in other places. The disparity with cars peaks at 20-30 minutes’ travel time.

Sydney and Melbourne have the best public transport accessibility among Australian cities, followed by Perth and Brisbane. It could be higher still with better-located station entrances and exits.

30-minute job accessibility by public transport in Sydney. Hao Wu and David Levinson

 

Cycling

This report identifies cycling as a viable option for improving accessibility. Assuming cyclists are willing to ride on the street, people cycling can reach about twice as many jobs as people on public transport within 30 minutes in all eight Australian cities, and around one-third of job opportunities reachable by car (except for Perth, which is 16%). Sydney and Melbourne have the highest cycling accessibility.

Of course, it should be recognised that many potential bicyclists are extremely uncomfortable riding in traffic. Their accessibility on a more limited network of residential streets and protected bike lanes would be much reduced.

30-minute job accessibility by cycling in Sydney. Hao Wu and David Levinson

Walking

People walking cannot travel as fast as those on other modes, particularly over longer distances, where public transport and cars can travel at much higher speeds. Not surprisingly, walking has the lowest accessibility of all four modes. The presence and timing of traffic signals that give priority to cars significantly reduces walking accessibility.

Walking accessibility is closely related to urban density. City centres, especially those in larger and denser cities, tend to have better walking accessibility.

Among the eight major Australian cities, Sydney and Melbourne have the best walking accessibility. Hobart and Darwin have the lowest.

30-minute job accessibility by walking in Sydney. Hao Wu and David Levinson

Job-worker balance

The job-worker balance of a place is measured dynamically as the ratio of jobs and resident workers reachable within 30 minutes. City centres have superior accessibility to both jobs and workers, and less pronounced advantage in car accessibility compared to other modes. Higher jobs-to-workers accessibility ratios in city centres show that, in general, jobs are distributed closer to and better connected with city centres than residential locations.

The job-worker balance is a potent indicator for identifying urban centres and for measuring the strength of centres.

Ratio of 30-minute job accessibility to worker accessibility by car in Sydney. Hao Wu and David Levinson

Conclusions

This research gives us a baseline accessibility measurement using the best available data for 2018. Repeating this analysis over time will enable long-run tracking of accessibility as a performance measure.

This will enable us to answer questions such as: is accessibility by a particular transport mode rising or falling? Is that due to congestion, network contraction, new infrastructure, or changes in residential or employment density? Are policies working to expand accessibility for the population as a whole, and for areas within cities? Which investments give the most accessibility “bang for the buck”?

Some of the results are surprising – in particular, the observation that the speed of Perth’s freeway and street network more than compensates for more limited scale in producing 30-minute car accessibility.

But this result is just an indicator of broader accessibility, which includes additional relevant opportunities, more times of day and more information than is presently at hand. This is likely to become more widely available in an era of big data if governments choose to actually implement the open data claims they advertise.