Advertisement

Are trams the correct answer?

Oct 24, 2013
An Adelaide Metro bus. Photo: Nat Rogers/InDaily

An Adelaide Metro bus. Photo: Nat Rogers/InDaily

South Australia’s transport plan is betting heavily on trams. They’re going to be the panacea to all our ills – they’ll increase residential density, activate city streets, and shorten commute times. But they’re also much, much slower than trains, and much more expensive than buses. Has the State Government backed a horse running in the slow lane?

Currently Adelaide’s public transit network relies on about 1000 buses to transport more than 80 per cent of its passengers. That’s set to change under the transport plan, announced by Premier Jay Weatherill earlier this week.

“If you talk to public transport economists, they’ll say a city like Adelaide should concentrate on buses because you can deliver a lot more bang for your buck than trams”

He’s spruiking a new network backbone based around five new tram lines radiating in a spoke out from the CBD and down nominated development corridors. Parts of the existing bus network – which currently ferries people from across Adelaide into the city – will be reconfigured into feeder services which will take people from the suburbs to the trams.

The switch away from buses may at first glance be welcome to commuters who have grown tired of the State Government’s struggles to get the bus network to run on time. But it’s not that simple.

Buses make a lot of sense to transport economists. They’re really cheap (something which both economists and governments approve of) and because they can run through multiple streets they have large catchment areas – a single bus can collect passengers from many locations.

“If you talk to public transport economists, they’ll say a city like Adelaide should concentrate on buses because you can deliver a lot more bang for your buck than trams,” says University of South Australia public transport expert Dr Andrew Allan.

“Buses are cheaper to providers, there’s probably bigger economies of scale, you can run it on the existing road network, you can do it on the cheap.”

So do trams make sense?

 Former South Australian Transport Department head Derek Scrafton, now based at UniSA, is a hard-headed bus advocate. He believes a city like Adelaide is still best-served by a bus network.

“The efficient element of the public transport system is the buses. But we’ve squeezed the buses to the point where we can’t squeeze them anymore,” Scrafton said.

Scrafton also questions whether commuters will be happy taking feeder services that ostensibly take them sideways rather than to their destination.

But buses make less sense as a city develops – as the State Government is hoping Adelaide will.

Density is the governing factor in public transport, says Allan. The more people living in a given area the cheaper and quicker public transport becomes because it doesn’t have to run as far to collect passengers.

Transport economists put density on a sliding scale. Areas with low density are best served by buses. As density increases, trams become viable. At areas of both high density and high distance from the city centre, trains are the preferred transit mode.

So do trams make sense?

The Transport Plan's map of the five proposed tram routes

The Transport Plan’s map of the five proposed tram routes

Currently Adelaide’s one tram line runs only through zones of high residential density – that might be the secret to its success.

But the planned tram lines will not run into such fertile territory.

The outer halves of the northern and southern tram routes run along areas of low residential density, as does the inner half of the western line.

The Port Adelaide line is perhaps the most poorly-placed on this measure – nearly its entire route runs through low-density areas.

Interactive: Adelaide’s urban density, 2011

Perhaps the biggest advantage of trams is the impact they have on the area they run through. As the transport plan notes, tram lines are key drivers of increased land values, development and densification – all goals of the State Government for the inner city.

Why is this? Allan speculates it has something to do with the permanence of a tram track; a developer can look at it and know their development will have prime transport links for at least the next 20 years. The same cannot be said for a bus stop.

“Trams support walkable communities and transit-oriented development very well.

“Buses, they don’t seem to attract developers. They don’t seem inspired to increase density on the basis of bus routes, because it can disappear so quickly.”

Allan estimates trams in the inner suburbs wouldn’t be able to run more than 25 km/h, up to maybe 45 km/h in the middle and outer suburbs. That compares to an average operating speed of about 70 km/h for a train.

But the plan’s reliance on trams to move people long distances, a role traditionally given to trains, is questionable.

Trams are generally used for short distances, where their high frequency and regular drop-off points balance their slow speed. They typically have stops every 300 to 700 meters, and in normal use run at speeds between 15 and 70 km/h.

Train lines transport people longer distances faster because they have fewer stops, allowing them to reach and maintain high speeds.

“Light rail is really designed to move lots of people at short distances, rather than lots of people over long distances – that’s the role of heavy rail,” says urban planner Daniel Bennett, who is currently working on Sydney’s tram rollout.

Scrafton and Allan both agree.

“Trams, they’re very good for short to medium haul distances, but when you’re talking about long-haul distances they’re not fast unless you give them dedicated right-of-ways they would be running on the existing road network,” says Allan.

Allan estimates trams in the inner suburbs wouldn’t be able to run more than 25 km/h, up to maybe 45 km/h in the middle and outer suburbs. That compares to an average operating speed of about 70 km/h for a train.

“At the end of the day, your average operating speed isn’t going to be much better than road traffic.”

as with anything political, it may be politics – and not pure policy – that ends up shaping the finished result.

What that means, says Allan, is the Glenelg line is probably the maximum distance you could sensibly operate a tram at.

While the plan’s proposed east, north and south lines would all be shorter than the Glenelg line, the western line would be of a similar distance and the Outer Harbour line (which would be converted from the existing train line) would be significantly longer.

One option for offering high-speed tram services would be running a double-track, allowing for one line to operate express. But the transport plan invisages trams running down existing major roads; two tram lines plus platforms would leave almost no room for cars.

Even with a single line, retrofitting trams to Adelaide’s busiest roads also poses problems. For example, Unley Rd would struggle to accommodate a tram line – including regular stop platforms – without the narrowing of sidewalks.

“You put in a stop, you need more room, and you’ve got to push other things out of the way,” says Bennett.

Every transport expert spoken to for this article praised the actual existence of the plan; a plan of course being better than no plan at all. And we still don’t have enough detail on the specifics to draw truly informed conclusions. But from an early vantage point in the process, the plan looks bold and well-intentioned, if not  without its problems to solve. But of course, as with anything political, it may be politics – and not pure policy – that ends up shaping the finished result.

Local News Matters
Advertisement
Copyright © 2024 InDaily.
All rights reserved.