Disclaimer: This is a post about a research project I led at work. My policy is not to blog about things that I’m working directly on, but in this case the research has already been reported elsewhere. All facts and figures in this post are drawn from a summary of my research and some related work that was presented to the City Centre Advisory Board.
Since I started working in the Auckland city centre in early 2012, I’ve noticed big increases in the number of people walking around the city centre. During the midday peaks, many footpaths are now filled to the point of overflowing. And there are increasing numbers of people walking around until late in the evening. This isn’t just a figment of my imagination: the available monitoring data confirms that the footpaths are getting busier.
This is good economically (more people walking around means more retail opportunities) and good socially (busy areas are generally safer and more interesting). So viva walking.
It’s also worth noting what hasn’t happened over the same time period. The number of cars entering the city centre during peak times has basically held flat since 2000, meaning that public transport has catered for all of the growth. This means, in turn, that the ratio of people on foot to people in cars has significantly increased.
There are a lot of places in the city centre where people in cars and people on foot must interact. Intersections, for instance: Signal timing dictates how much time cars must wait for a green light, and how much time pedestrians must wait for the green man.
The common (but not universal) practice in New Zealand is to make decisions about signal timing based mainly on minimising delay for vehicles. People on foot are accommodated, but they aren’t necessarily prioritised. In a lot of contexts, this isn’t totally crazy – there are a lot of cars and not a lot of pedestrians, so you’ll get an approximately optimal outcome that way.
But in a busy city centre environment where there is a high and rising ratio of pedestrians to cars, you have to ask whether this is the right way to make decisions. On Queen St, there are around four times as many pedestrians as vehicles. On High St, there are around 13 times as many pedestrians as vehicles.
That’s what we tried to do in this research. We found that people weren’t counting delays to pedestrians at busy city centre intersections. So we set out to count pedestrians and pedestrian delay at two city centre intersections – Queen St / Victoria St and Upper Queen St / Karangahape Rd.
The Heart of the City’s pedestrian counters provide a great source of data on trends in pedestrian volumes, but they’re not granular enough to know what’s going on at individual intersections. For instance, there are a lot of people walking along Queen St immediately north of Victoria St – an average of around 38,000 per day in 2016. But how many of those people cross the intersection when they arrive at it, and how many turn onto Victoria St?
So we went out and gathered some data on what was happening at these intersections. On a sunny February day during the busy pedestrian hours (noon-1pm), we set up a few video cameras to record how people were using these intersections – ie whether they were crossing the street or going in a different direction. Here’s what we found for the two streets:
We then estimated the average delay per pedestrian based on data on signal phasing, cross-checked against measured pedestrian behaviours. We assumed that:
- People who arrive during the traffic phase must wait until the next pedestrian phase
- People who arrive during the pedestrian phase with enough time to safely cross will simply walk across, with no delay
- People who arrive near the end of the pedestrian phase, with too little time to cross safely, must wait until the next pedestrian phase.
We found that:
- The average person walking through the Queen St / Victoria St intersection was delayed by 27 seconds relative to the ‘free flow’ walking conditions that they would experience in a shared space or pedestrianised environment
- The average person walking through the Upper Queen St / K Rd intersection was delayed by 38 seconds relative to ‘free flow’ conditions.
To conclude, we estimated annual pedestrian delay outcomes using the Heart of the City’s pedestrian count data and applied the NZ Transport Agency’s Economic Evaluation Manual parameters to estimate the equivalent monetary value of wasted pedestrian time. The figures added up quite rapidly:
- People walking through Queen St / Victoria St experience annual delays of 161,000 hours, which ‘costs’ around $2.2 million per annum
- People walking through Upper Queen St / K Rd experience annual delays of 40,000 hours, which ‘costs’ around $0.7 million per annum.
We also extrapolated our findings out across the entire Queen St corridor based on pedestrian count data and information on signal timing. The results were interesting – we found that delays at successive intersections, all with relatively high pedestrian volumes compared with car volumes, added up quite quickly – to perhaps $12 million in cost of delay per annum.
I’d like to make three points about our findings.
The first is that pedestrian delays in the city centre can have ramifications for Auckland’s transport system as a whole. The city centre is a major public transport destination, but it’s also an essential transfer point between services that serve different parts of the city. People transferring between services must often cross major intersections, where delays may cause them to miss a bus or frustrate them to the point of skipping PT and driving instead. (As highlighted in Shan’s great posts on Wynyard Quarter connections.)
But there’s also an opportunity. Building light rail down Queen St and creating a pedestrian mall up and down its length will significantly reduce delays for people walking on the corridor. Our analysis shows that reduced intersection delay for pedestrians could make a significant contribution to the benefit-cost ratio for the project.
Second, while it may be challenging to reduce pedestrian delays to zero, due to the need to let vehicles through many intersections, we can significantly reduce these delays with relatively simple changes.
For instance, we had information about recent changes to signal timing for the Queen St / Victoria St intersection. At the moment, there’s only one pedestrian phase per signal cycle. If you get unlucky, you will have to wait for both northbound/southbound traffic and eastbound/westbound traffic, which can take a minute and a half or more. But prior to changes made to ‘optimise’ city centre traffic flows, there were two pedestrian phases per signal cycle. The old signal phasing cut pedestrian delay by around one-quarter.
Reducing the cost of delay by 25% with one simple change: seems like a good opportunity.
Third, I was amused to see how these results were reported. For instance, here’s the headline in Stuff:
Auckland’s poor pedestrian flows cost $186m every year
Packing in pedestrians costing Auckland $186 million a year
These headlines are not accurate. As shown in the above figure, our estimate was that the annual cost of pedestrian delay on Queen St intersections was around $12 million. The discounted present value of delays over a 40 year period was estimated to be around $186 million. (This assumes no future growth in pedestrian volumes, so it’s likely to be a conservative figure for the present value of delays.) Furthermore, these delays aren’t necessarily an economic cost. Delays will affect some people who are on the clock (walking to meetings, delivering parcels), and some people who are out shopping or walking to work.
I guess this goes to illustrate how “cost of congestion” studies are reported in general – there’s a tendency to seize upon the largest number, ignoring relevant caveats about that figure!
What do you think about pedestrian delay in Auckland?