Following on from my post a few days ago on light rail being preferred to the airport – which has been one of the most commented on that we’ve ever had – by far the most common concern is around the speed of light rail, particularly on the section along Dominion Rd.
I’ve taken a look in the past at what other cities who have built similar light rail systems to what AT are proposing and I found that a number of them are capable of the speeds suggested. But of course they aren’t Auckland so I thought I’d take a quick look at some of the things we know that AT are proposing that will help ensure light rail will be quick and reliable along this important corridor.
Fewer stops and more direct route
Buses along Dominion Rd between the Southwestern motorway and the centre town have almost 30 stops to pass along the way. There are of course bus lanes along a lot of the route but they stop short at key intersections which can cause delays. Before light rail came along, AT had planned to lengthen these bus lanes right to the intersection to help speed up buses further. The current timetable shows travel times between Denbigh Ave close to the motorway and the city taking between about 23 minutes and 41 minutes depending on the time of day.
With light rail Auckland Transport plan to significantly reduce the number of stops along the route with just eight on Dominion Rd itself and only 10 to get to the same point in town. Of course one down side to some residents is it means they may have to walk further to get to a stop. For light rail it appears they’ve effectively picked one stop in the main centres along the route with intermediate stops between them.
You can see the difference in the two in the map below. Fewer stops means vehicles can travel faster as they’re not constantly accelerating or braking.
Buses can also suffer from dwell time issues from boarding and alighting passengers. It is possible to address some of these, such as restricting cash payments, allowing all door boarding which could speed up buses a bit but off line ticketing and fast boarding are a fairly standard feature of light rail so provided that AT implement it properly that will help compared to the current situation people compare to.
In addition to fewer stops, you can see from the map above that light rail takes a more direct route to the city and so has fewer intersections to negotiate.
Buses currently are at the mercy of traffic lights and at the big intersections with long cycle times this can slow them down and cause buses to bunch. When bus frequencies get too high it results in there almost always being buses waiting to get through lights, which is often a leading cause of them bunching and is not good for operations or passengers.
One reasons we heard AT were for looking at light rail on Dominion Rd in the first place was that it allowed fewer but much larger vehicles to run. The advantage of that is it allows for signal priority to be effective and so depending on how it is set up, it could mean the light rail never has to stop at Intersections other than at its stations. Again that could end up being a significant time saving.
On a related note, we know that light rail will be able to skip one major intersection with AT have suggesting that they will tunnel under the K Rd ridgeline as part of building that part of the line. I believe this is mainly for operational reasons – removing a steep part of the hill – but it will also benefit travel times.
Centre running protected route
Running light rail down the centre of Dominion Rd means it won’t get held up by cars turning left into side streets or driveways, parking to run into the shops or drop someone off/pick them up. Cars would only be able to turn right at specific intersections and not when a light rail vehicle is around. It is also common for the light rail corridor to be protected by a raised kerb to prevent cars from accessing the tracks or using them as a median, in much the same way that kerbs are used to stop people driving in cycle lanes. Examples include the Gold Coast as shown below and Seattle.
A raised kerb can also be seen in some of the concept images AT have released in the past such as this on of Ian McKinnion Dr
When you combine all of these elements it means that light rail is able to travel down Dominion Rd pretty much completely unimpeded by other traffic and only needing to stop a few times along the way. The speed limit for light rail would almost certainly still be 50km/h but even if it could average half that, it could travel the 7km between the centre of town and SH20 in just 17 minutes. As a quick comparison, in the same timeframe leaving from Britomart would be at about Ellerslie – although admittedly we expect AT go get that time sped up a bit.
Once the route reaches SH20 the LRT route appears to be almost completely separate from traffic with the exception of a small section in Onehunga and so for most of it could easily travel at up to 100km/h if the vehicles and tracks were designed to do so – and that has been suggested by AT in the documents they’ve produced so far.
This gives me confidence that for LRT at least, the times AT have suggested are realistic but I’d add that a lot depends on just how well they implement everything.