This case study of rapid transit in the Molonglo Valley shows that corridors for vehicular traffic and light rail may have something in common, but public transit corridors are poorly suited for a cycle highway (transit). Cycle networks are different.
Genesis
A case study for rapid transit in the Molonglo Valley (Molonglo: A case study in transit-friendly suburban structure, Human Transit, Jarrett Walker, 2011), was sent to canberra.bike by Ryan Hemsley, Chair of the Public Transport Association of Canberra (PTCBR). This case study outlines the design principles behind the Concept Plan for the Molonglo Valley. The 2004 Canberra Spatial Plan identified the Molonglo Valley as a Future Urban Area. Public transport was recognised around this time as an important part of the future transport network, which led to the introduction of the “rapid” bus network and light rail. The curved John Gorton Drive is optimised for rapid transit.
Mechanics of rapid transit
Rapid transit is public transit at speed. The presumption of rapid transit is that distances are large and not walkable. Rapid transit seeks to lure people out of their cars and into buses and the light rail instead. Rapid transit must be fast so that travel times are competitive with driving a private motor vehicle.
For rapid transit, travel time depends on both route distance and service frequency. We are all familiar with waiting for the bus. The waiting times are shorter if the service frequency is higher. During periods of low service frequency, such as on weekends, we can wait a long time for the next bus. Walking to or from a bus stop adds further to the travel time. The walking time is reduced when more people live closer to rapid transit stops, and the wait time reduced by a more frequent service.
ACT Transport is a complex operation. A balancing act between service, infrastructure, personal, and commercial considerations. There are limits to the number of buses that can run. Transport Minister, Mr Chris Steel, stated recently to the Molonglo Valley Community Forum that every single bus available is running during peak periods. More buses could be purchased, but every bus needs a driver and a bus depot to keep it operational. There are other restraints. It costs money to buy and run a bus. As with cars, we can consider the total cost of ownership over the asset’s life. The more buses you have, the greater the cost. Alternatively, we could have better buses, but run them more regularly rather than have them stand around. The demand for a bus service varies with the time of day and day of the week. At peak periods, ACT Transport does not have enough buses, and at night too many.
Other ways to improve service frequency are less obvious. The easiest way is to decrease the total route distance and have the existing bus fleet travel these routes more frequently. The network is redesigned from having many short routes, to fewer routes that service a large portion of the population more regularly. Most are now better off, but those living on the edge of Canberra may be disappointed.
Rapid transit works best if the population lives closer to the routes. The concept is ill-suited to a sprawling city (low density housing), but works well with medium density housing that is built close to the rapid transit corridor. This is not typical for Canberra, where low density housing prevails, but we will see this along John Gorton Drive.
Molonglo C-shaped corridor
The concept plans for the Molonglo Valley were shaped by the characteristics of rapid transit. The location of the Molonglo Valley, west of Canberra, suggest that people will travel north to Belconnen, south to Woden and east to Civic. A direct route to the Parliamentary Triangle was discarded early in the planning as unworkable.
The Molonglo Valley is clearly segregated by the river into north and south sections. The rapid route to Civic starts in the north of the development, rather than from the district centre. Effectively, Molonglo Valley is built along a north-south corridor connecting Belconnen with Woden.
The rapid transit route through the Molonglo Valley is a C-shape between William Hovell Drive, in the north, and Tuggeranong Parkway, in the south. It is part of a large loop from Civic to Woden and returning through the Molonglo Valley, and back to Civic. Rapid transit would run in both directions at regular intervals, and works best when the majority of the population lives close to the corridor.
It might seem strange that we travel first to Woden or towards Belconnen to go to the city, but, due to the mechanics of the rapid transit, the route permits a more frequent service and avoids the wait times from having many scattered routes.
The explanation why John Gorton Drive is a C-shape
If you are thinking like a motorist, this is silly. Why would we carry people to their destinations by the most direct possible route, which in many cases would be east-west? The answer: because transit travel time includes the waiting time imposed by frequency, and to maximise frequency, we need to run the fewest possible route miles of rapid transit service. The more distance we need our lines to cover, the less frequently we can afford to run them.
Approaching only via the ends of the C means that our transit lines can run along the spine of the C, serving many parts of Molonglo without having to branch. That means, in turn, that our frequency remains concentrated, instead of being dissipated as branching would require. In short, you may have to travel a slightly longer path than you would go if you were driving, but only with this patter can we ensure that you will have services coming whenever you need it.
Molonglo: A case study in transit-friendly suburban structure, Human Transit, Jarrett Walker (2011), 202.
Impact on cycling
The C-shaped design route for the Molonglo Valley makes sense for rapid transit. Driving the extra distance may not bother the commuting motorist with high travel speeds of 80 km/h. The Molonglo Valley is not that far from Civic or Woden, so a circular route is workable.
Cycling is different. A cyclist may achieve an average speed of 20 km/h. The average speed depends on many factors, including the quality of the paths, the frequency of road crossings and, to a lesser extent, the hilliness of the terrain. At low gradients, the hilliness of the terrain is not as important as one would first think, as the time lost riding up a hill is recovered riding down. The most important factor to shorten cycling travel times is directness.
The C-shape design of John Gorton Drive is not ideal for cycling, as the route to Civic is longer. Assuming a direct distance of 10 km, the circular route would be 15.7 km – 57% longer. The travel time increases accordingly from 30 to 47 minutes. Compare this to driving at 80 km/h with an increase in the travel time from just 7.5 to 11.8 minutes. The time savings with a direct route is only 4 minutes by car, but 17 minutes by bicycle. Except at peak periods, a bike is disadvantaged by C-shape designs.
An indirect route could be made sustainable with electric vehicles – both buses and cars – and the travel time will be about the same. Bikes, however, are human powered and there is no way to shorten and quicken travel times other than making the route more direct.
Rapid transit routes are circular. Cycling networks are hub and spoke, or grids.
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Congestion
Driving 15.7 km to the city will take longer than 11.8 minutes predicted due to congestion. In Canberra, the average commute to work is less than 10 km[1] and the average time commuting to work was 51.5 minutes in 2017.[2] Cycling helps reduce congestion, as it frees up roads. However, it is hard to make cycling attractive to people, despite all its benefits, without direct routes that are safe and of a perceived good quality. Canberra’s cycling infrastructure is currently inadequate – due to both design flaws and years and years of neglect. Back in the 70s and 80s, we made a good start, but the 40-year-old infrastructure is no longer fit for purpose. While the roads have improved, the cycling infrastructure generally has fallen behind.
The premise of rapid transit is that a bus can travel at high speed over the length of the route. Without dedicated bus lanes, a bus will only be as fast as the rest of the traffic. Do we then prefer to sit in a car or a bus? The car is more private and comfortable, but also more expensive. The bus is cheaper but slower overall, when we factor in the walking to the bus stop and wait times. Without bus lanes, public transport is unlikely to be the first choice of many motorists, who have not grown up as regular users of public transport.
Canberra light rail is a rapid transit option, providing a high speed service on dedicated infrastructure. Referring to the light rail as a tram is incorrect, as a tram shares the road with the cars and ends up stuck in congestion.
[1] ACT and Queanbeyan-Palerang Household Travel Survey, ACT Government, 2018, <https://www.transport.act.gov.au/about-us/planning-for-the-future/household-travel-survey> [accessed 7 July 2021].
[2] Wilkins et. Al., HILDA, Melbourne Institute, 2019, 79.
Marginalisation of cycling
Cycling is marginalised by the dominant thinking of our city planning. Cycling, as transport, is sidelined in place making as it could conflict with pedestrians. Place making is about making desirable destinations. Schools, shops, and town centres are destinations, and we would like to ride to them.
Cycling is also seen by some to be at odds with motor vehicles. Bicycles are permitted on roads (as a vehicle), but the cyclist is a vulnerable road user, too. A cyclist travels much slower than a motor vehicle and is hard to see on a busy road due to cognitive limitations. Collisions between a high speed motorist and a cyclist will almost certainly lead to serious injuries to the cyclist, and possibly even death. Cyclists do not seem to belong on the road, either.
This article reveals that the design principles of rapid transit are at odds with the cycling transit networks. Rapid transit networks for future urban areas, such as Molonglo, will be different to that required for a good cycling transit network.
Cycle corridors are rapid transit routes for cyclists. Cycle highways are trunk routes for commuting cyclists between town centres. To be able to build them, we must reserve and preserve cycle corridors. The cycle corridor is the foundation of a plan that may take decades to build.
Designing cycle corridors
We would conclude that if direct routes do not work for rapid transit but, on the other hand, rapid transit meshes with an arterial road network, that road and rapid transit corridors could be combined. Here we must conceptually separate the idea of sharing a corridor and sharing infrastructure. Light rail will always have facilities designed for it, as will cars have facilities designed for them (roads).
Similarly, within a suburb, Local Community Routes (LCR) may be shared by pedestrians and cyclists – but may still have separated paths (facilities), depending on the urban context, and the speed of movement.
Commuting cyclists, who travel greater distances between town centres, must have dedicated bike paths to cover the distance quickly and economically. Cycle corridors need to be reserved and preserved for the construction of cycleways for high speed cycling. Cycle highways are at the top cycle route hierarchy and require their own infrastructure. Corridors optimised for cars and light rail will most definitely not do.
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