Why frequency is key for metropolitan transit
Metropolitan transit is the opposite to all the above. For a start trips are shorter, cheaper and thus more frequently made. Travel time predictability is essential as travel may be to time-sensitive jobs, school lessons or appointments. But finish times can vary so the system must also be robustly amenable to changes of plan.
Want all the above in on a public transport network? Good frequency on as many routes as possible is key. If you don't have it then the network isn't very useful as waits can easily exceed travel times. Yesterday I devised the 'five smileys' diagram below that I think summarises this neatly.
Prevalence and user experiences of various service levels
Melburnians loathe 40 minute frequencies yet they plague our bus network, including on some of our most productive routes in western and northern Melbourne. I have no doubt that 40 minute frequencies cause much of the deserved low regard that buses are held in. Key train lines to destinations like Wyndham Vale, Sunbury, Broadmeadows, Coburg, Epping and Greensborough are also only every 40 minutes, notably Sunday mornings but sometimes other times as well. The short-changing of the north is very obvious in the frequency map presented last week.
40 minute headways lack the 'memory timetable' that services every 60, 30, 20, 15 and 10 minutes have. Perhaps their only merit is that they harmonise with trains every 20 minutes, as typical in Melbourne's west, north and outer south-east. Hence 40 minutes is a very common off-peak frequency for bus routes, even though the patronage on some in areas like Tarneit, Point Cook and Craigieburn would easily justify a 7 day 20 minute service.
Every 30 min
30 minute frequencies are what make our SmartBuses not so smart on weekends and most of our rail network inconvenient for evening and occasionally also daytime travel. Even trams have half-hourly gaps on Sunday mornings and evenings. Like with every 40 minutes, a 30 minute wait due to a just missed connection, can double travel time for most trips.
Still there's one thing worse than 30 minute waits and that's the abovementioned 40 minute gaps. Getting this to every 30 min is a small but worthwhile improvement. And it's super-cheap. This is because a 30 minute frequency is four trips every 2 hours versus three for a 40 minute frequency, you just need to add one return trip per two hours to boost the service.
Even better would be one additional earlier return trip to cut the earlier 70 minute gap (before 7:56am) to 40 minutes. That's a lot of value for just two extra return trains per week. Similar Sunday morning gains are possible for at least parts of the Sunbury, Upfield, Craigieburn, Hurstbridge and Sandringham lines with a combined total of 12 return trains per week. That's about 24 trips each way, or about 100 per month. For context Metro runs about 64 000 train services per month (November 2019 figures), meaning an increase of just 0.16% in monthly services.
That's tiny in the whole scheme of things given it would get almost our whole rail network from a maximum 40 to a maximum 30 minute wait for 18 hours a day / 7 days a week. It does not speak well for the planning, leadership and internal advocacy capabilities of DTP that Secretary Paul Younis has been unable to win government support for even these minor upgrades implemented across the rail network.
Every 20 min
I have seen 20 minutes referred to as a 'check and go' frequency - in other words you are still looking at a timetable but it does not require the sort of detailed planning that you might do for a 30, 40 or 60 minute headway.
The roll-out of much more 20 minute service was proposed for metropolitan rail lines and bus routes in 2012's Network Development Plan (Metropolitan Rail). This plan wasn't much favoured by the following government. Still, Werribee, Williamstown and Frankston train lines gained maximum 20 minute waits in the good but undersold 2021 rail timetable change. And before then quite a few bus routes gained 20 minute service.
20 minute service is not something that people are begging politicians to implement. It's less saleable than every 10 minutes in that regard. But it's also vastly cheaper to do over multiple lines if your starting point is 30 or 40 minute service. The fine print of the diagram lets you compare the relative cost of upgrading to the next higher frequency in terms of extra trains, trams (or buses) per hour.
As noted before, a boost from 40 to 30 minute is the same as going from 3 to 4 return train trips every 2 hours. That 0.5 extra trips per extra hour of improved service.
The next step, of going from 30 to 20 minutes maximum waits, needs an additional return train trip per hour to be added. That's a bit dearer but is still a bargain when it is recalled that most of rail's costs are fixed. Also you've shifted the whole perception of the rail network from 'at worst bad' to 'at worst neutral' by halving maximum waits from 40 to 20 minutes.
These gains hugely aid reliability, build network robustness and cut travel time variability, especially when rail replacement buses operate. A similar 30 to 20 minute upgrade would also assist our popular SmartBus routes, which with few exceptions run their frequent service on weekdays only.
The better you make something the more people use it. Thus upgrades to this and even higher frequencies induce higher patronage, especially during off-peak times. With rail you could get a lot more 20 minute service with a small increase in monthly service.
To use round numbers, the Melbourne rail network averages about 2000 trips per day. A 1% increase is about 20 trips, or 10 return trips. Adding one return trip on 10 lines with 30 minute evening service would give an extra hour where services are every 20 rather than every 30 minutes. Go for a 3% increase and the maximum evening wait falls from 30 to 20 minutes until about 10pm network-wide. The point is that you can do a surprising amount with just a 1 to 3% increase in monthly train services, with about a 5% rise needed to finish the job.
Buses would need a bigger percentage increase as they're usually less frequent to begin with, especially on weekends. But trams would need a much smaller increase as their timetables are already every 20 minutes or better except for early and late on Sundays.
Every 15 min
15 minute frequencies are largely confined to a few lucky train lines in the east and some weekday buses (notably premium SmartBuses). Many trams have 12 or 15 minute off-peak and weekend frequencies. 15 minutes is about what many people start to consider as turn-up and go for a single trip. It's only one extra trip per hour compared to 20 minutes and two extra trips per hour compared to 30 minutes so is fairly economical.
While an improvement on all the previously discussed frequencies, 15 minutes is still not great for trips involving a change. This is because waiting could still amount to 30 minutes of total travel time in the worst case. An unreliable 15 minute service is also poor as the cancellation of just one train opens up a half hour gap, with similar issues possible for delayed main road buses stuck in traffic. This you might have 15 minute service as a top tier service in a small to medium sized city but a large city requires something better.
Every 10 min
This is proper turn up and go service suitable for key suburban lines in a major city. It requires 2 extra trips per hour compared to 15 minutes and 4 extra trips per hour compared to a 30 min frequency. Thus you don't go running 10 minute service on every back street bus route.
Still a 10 minute frequency makes the network vastly more transfer-friendly, encourages sympathetic transit-oriented land use and lifestyles and makes road time and space re-allocation (including traffic light priority and bus lanes) more justifiable. All this induces even higher patronage. And scope exists for bus network reform to deliver 10 minute frequencies on key corridors in parts of Melbourne that really need them (eg around Northland and Highpoint shopping centres).
Widespread 10 minute frequencies were a major service aim in 2012's Network Development Plan (Metropolitan Rail). That plan also specified it for trams and top tier bus routes in its multimode coordination framework. Reference to this framework was regrettably omitted from the Victorian Bus Plan released 982 days ago today.
Nevertheless there has been some progress towards more weekday routes every 10 minutes, notably the Route 202 Melbourne University shuttle and routes 235 and 237 in Fishermans Bend (which provide a welcome precursor for a tram unlikely to be built soon).
Other cities and expectations
The above is a Melbourne perspective. Those from large Asian, European and even some Canadian cities expect far higher frequencies than typically run in Melbourne. A Melburnian would very happily accept a 9 minute wait for a 10pm train while a Torontonian or Vancouverite would grumble.
Even Sydney's expectations would be higher. In contrast, Brisbanites would set their sights a little lower than us, with most Canberrans, saddled with embarrassing 120 minute weekend bus headways, a lot lower.
What do we want from our network?
Then there are more objective measures such as what you want the network to do. If it's to provide a versatile all day service for a multitude of trip types and destinations then there is going to be more interchanging (at all hours). Passengers have a certain 'interchange time and inconvenience budget' for each trip they make. If the network imposes anything beyond that they people will either drive or not travel at all.
Day and night high frequency is a necessary condition for the versatility the network needs to grow its role and patronage. Official understanding and responsiveness has varied over time.
Understanding probably peaked during several decades between which the rail network was primarily regional and goods focused (late 1800s) and when it became a more extensive electrified but narrowly suburban commuter service (post 1950s). During this early to mid 20th century 'sweet spot' the trams, trains and even some buses were double their current frequency, especially at night, albeit on a smaller network than now.
Suburbanisation, electrification extensions and core area off-peak service cuts followed. Interest in frequency narrowed to become solely as a means to maximise peak capacity rather than as a benefit in itself. The peak of this narrow commuter thinking was probably the 1970s when the City Loop was under construction (for the commuters) but evening timetables were savagely cut in 1978. Not unsurprisingly public transport reached historic patronage and mode share lows around 1981 (when Melbourne was losing prestige to Sydney and jobs were suburbanising).
Subsequently patronage recovered (albeit in a larger city) and some service frequencies were restored. Indeed day and night services on the politically marginal Frankston line are now more frequent than they've ever been. Ideally we'd have continued with NDP Metropolitan Rail frequency upgrades in tandem with bus reform that was then accelerating. Unfortunately this basically stalled with everything going on infrastructure builds instead.
Of these the Metro Tunnel is a better project than the one-trick City Loop. Similar could be said about the Suburban Rail Loop, though one might still quibble about timing, design decisions and costs.
The huge borrowing for these and other projects (including roads) may make it easier for government to say there's no money for service, given rising interest payments. Still, that's not what the Metro Tunnel banners say.
Let's hope they're right and its opening heralds a renewed realisation in the power of frequency that we've waited too many decades for.
Index to Timetable Tuesday items here
3 comments:
You're missing a sixth smiley: 💩 Every 60+ min
Night Network trains, the Stony Point line, and the vast majority of buses after 6PM and all day Sundays.
Even the 703 has a 60-minute gap on weeknights at around 10PM despite being a SmartBus, and its Saturday timetable finishes at all of 8:30PM forcing hourly Night Bus services to start well before midnight.
Of course, the Victorian Government in all its infinite wisdom also made sure that Night Network services don't apply to public holiday timetables or special events (e.g. Australian Open matches finishing at 2AM+) unless the following day happens to be an actual Saturday or Sunday. Forget public transport on a Thursday or Sunday night during a long weekend.
Could you do A Post about route 400 sunshine to laverton via the prisons?
The area around the 400 is discussed here, notably the 2014 reformed network. That has a link to a research paper that discusses 400 in more detail. https://melbourneontransit.blogspot.com/2019/07/5th-anniversary-of-reformed-brimbank.html
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