Tuesday, June 30, 2020

Panic buying or inflexible systems?

Early on in the coronavirus pandemic, the shops ran short of supplies.

There was no sanitiser gel to be had for love or money. Of course, there was wall to wall messaging about how important hand washing was, and how you should use sanitiser if you couldn't wash. Shortage of supplies in the shops means that people were paying attention.

Basic food supplies - pasta, flour, and the like - were scarce. Everyone looked at what was likely to happen, decided that the likelihood of needing to feed themselves at home without being allowed out was pretty high, and put an extra item or two in their basket.

I'm not quite sure how much toilet roll people thought they needed, but being stuck at home means you're going to need more.

I think there's fairly widespread understanding that the the term panic buying was completely misleading. This was (and there will always be the odd exception) a simple adjustment to changing circumstances.

Or, rather, a couple of changes.

The first is that being at home more means that you need more of almost everything. More food, more household supplies. Less petrol in the car, at least for most of lockdown.

Of the 100 days or so we've been locked down, we would normally have been on holiday or a trip for something like 7-10 days. And we would probably have gone out to a pub or restaurant for a meal 5-10 times in addition to that. So that's between 10 and 15 days that we wouldn't have been at home - eating or using other materials. (The Cambridge Beer Festival would have added a whole extra week to that, but that's a slightly exceptional event.) Just because of that, our weekly supermarket spend is going to be up 10-15%.

Other people won't necessarily have the same specific changes, but a lot of people eat out, use takeaways, get schools to feed their children one meal a day, or grab food on the go. So the idea that demand on supermarket supplies in general might be up 10-15% seems plausible.

Recently, Tesco have reported about a 10% increase in demand, which aligns with this. Of course, pubs and restaurants are seeing the other side, with a precipitous drop in income. The overall amount of food required doesn't change, it just gets into peoples stomachs via a different supply chain.

And the supermarket business is pretty cutthroat. The supermarkets have spent years optimising their supply chains to stay competitive. None of them have the slack in their systems to cope with a sudden 10% uptick in demand - if they kept that much headroom in normal operation they would get wiped out in short order.

The second change is in when people shop. We always used to shop twice a week. This is good, you get fresher produce and each shopping trip is more manageable. But now, and this seems to be general, we're making fewer - but obviously larger - shops.

The shift from twice a week to once a week means there's going to be an initial surge. That first shop will have half a week's extra stuff in it, and you end up with everyone having half a week's worth of additional supplies. And just the knowledge that you can't (or won't) simply nip in if you run out means that you're obviously going to have to stock up a little earlier. So there's this sudden surge to add 3 or so days worth of food. Once it's stabilised, of course, it goes back to normal.

We haven't gone for online shopping yet, for the main shop anyway. The supermarket is only a few minutes walk away so it's pretty silly for us. What we have used online ordering for is some of the more specialist items that the local supermarket doesn't carry - the luxury of being able to visit multiple stores is one we've avoided for now.

Longer term, I think it's going to continue in the current state for a while. I really can't see a widespread shift back to pre-pandemic behaviour. People will go out, of course - if only because they're a bit stir crazy - but the idea of going out will soon lose its charm. The hospitality sector is probably going to have to reinvent itself entirely.

The changes we've seen didn't result in the overall volume of demand changing, just in where and how it appeared on the demand side. We have the prospect of the ongoing Brexit fiasco disrupting the supply side, stressing the system again.

Sunday, May 31, 2020

On being under lockdown

A while ago I wrote about On working from home.

Of course, the recent COVID-19 crisis has meant that a lot more people are working from home. Although we have to be honest and say that this isn't the normal working from home, it's having to try and work in isolation away from the office because of the pandemic.

Even for those of us used to working from home, this isn't normal.

When I decided to work from home, one of the things I had to consciously think about was how to manage the process. Without the need to leave home and interact with other human beings that comes with working in a shared environment, getting out of the house and going to lots of events was key - museums, talks, meetups, and the odd beer festival. Pretty much all of that has gone out the window.

It's unfortunate timing too. As a general rule things are quiet in the winter months, the weather and lack of light don't help. So I was just looking to come out of mini-hibernation when the pandemic comes calling.

I'm fortunate that the actual work part doesn't change much. The at home has been quite different. Mrs T has also been stuck at home, so I don't get the house to myself during the day. I mean, I like her around, but she has been getting underfoot a lot. (Not to mention the occasional call for IT support.)

Far more so than myself, she's gone online to socialize in a big way. We professionals might turn our noses up at Zoom (and expecially its security) but you have to concede that it's ideal for consumer chat. Even better, and unlike pretty much everything else, it works great on my old retired iPad, which has been heavily used. She's done quizzes, wine tastings, cocktail classes, cookery demonstrations, singalongs, dancing(!), afternoon teas, and just general chat.

Shopping has changed. We're fortunate in that we have a big supermarket just round the corner. Rather than the traditional minor shop twice a week, we've switched to a major shop every 8-10 days. Slightly oddly, as there's more in each shop, we now walk there and back (Mrs T does the shop, I walk over later to help carry it). The cars are basically gathering dust.

Where we are on the outskirts of Cambridge is fairly quiet anyway, but is now even quieter. The buses look empty, the roads are quiet. We go out for walks for a bit of fresh air and don't have to worry about keeping clear of crowds of people. (I'm a bit limited in this, hay fever discourages me from going outside too much.)

The Cambridge Beer Festival was cancelled. That's another major social event gone. Not to mention the volunteering time (minor for me, rather major for Mrs T). And the beer, and the food - especially the cheese! The festival organized a number of online events through the week, and we got in a good stock of cheese (I can strongly recommend Shepherds Purse, especially if you're a fan of blue cheese), found some good beers (or cider) online, and raised a glass at home.

Looking to the future, it's going to be a long time before anything approaching normality returns. There are always going to be those who just can't be bothered with the restrictions put in place, but I'm likely to be a hermit for a while yet.

Sunday, March 01, 2020

Free buses?

One thing that is absolutely clear in the battle against congestion and pollution is that modal shift away from the private car is essential.

The fundamental issue is space-efficiency. Cars are horrendously inefficient users of the precious limited space available in urban environments. It doesn't really matter what alternative mode is used - whether walking, cycling, bus, tram, or train - changing the mode is always a big win. No, self driving cars don't help, and may make matters worse. Electric cars don't help either, you still have to get the power from somewhere, and they still have significant particulate emissions.

For larger cities, trams or rail are key. There's still work to do to drive the cost down in smaller towns and cities, but things running on rail solve the particulate emissions problem. The problem is that, while efficient, they provide more transport capacity than smaller conurbations can take advantage of. In addition, it takes years to develop a rail network.

Which leaves buses. Not ideal in the long term, but available right now. How do we get people to move onto buses - and drive up ridership on public transport to justify investment in better solutions?

What about making public transport free? After all, Luxembourg has done it. Clearly adds to the attractiveness, but can we afford it?

Consider Cambridge. The city has a population of about 125,000; with the surrounding area we might consider a quarter of a million people are in scope.

Giving that many people free public transport will cost a fortune, and we can't possible afford it. Correct?

Not so fast. The MegaRider ticket is £15 for 7 days travel. Let's round that and say it's £2 per person per day. That's a charge at which the current bus service is profitable.

What's a reasonable estimate of the number of users? Not the whole quarter of a million. Pensioners already have bus passes. Some walk, some cycle, some are already close enough to a railway station. Some, for work purposes or for special needs, will be unable to use public transport. Let's say we're targetting 100,000 people 5 days a week. That's £1million a week, or £50 million a year.

OK, that's a fair amount of money to you or me. But the CAM project (Cambridge Autonomous Metro) is talking about an eye-watering cost that may reach £4billion. Instead of funding CAM, we could fund free bus travel for everyone in Cambridge for 80 years. The Greater Cambridge Partnership was talking about a £1billion investment for the City Deal. The recent A14 "upgrade" was over £1billion.

In those terms - and in terms of many of the other projects being proposed - funding free bus travel is a bargain.

We're not done yet.

Increased ridership means fuller buses, so utilization goes up. So the cost per journey goes down.

Increased ridership justifies a denser mesh with more routes, leading to greater efficiency, driving down unit costs.

Modal shift reduces congestion, cutting journey times, so you don't need as many vehicles or as many drivers to provide the same service, driving down costs even further.

Not charging means a massive reduction in boarding times, which as I've talked about before is a major contributor to delays and inefficiency.

It's not hard, within the city, to see journey times cut in half through this process. And maybe utilization can almost double. Which means that the actual cost goes from £50million a year to £20million a year. The CAM could fund that for 2 centuries.

And that's the fundamental thing. Pretty much every single transport project currently being floated costs more - often many times more - than simply making buses free. There's a downside here - providing free buses may be sufficiently successful in the short term that it could kill off the prospects for the better long term projects. But it gives us the breathing space to develop the better solutions without destroying our cities and the planet in the meantime.

And that's only covered the direct costs, ignoring the indirect benefits such as: reduced journey times and increased productivity; decreased pollution and better health giving savings for the NHS; cleaer street and a better public realm; and so on.

Perhaps we should be asking not whether we can afford to do this, but whether we can afford not to.

Tuesday, December 10, 2019

The prospect of limiting carbon emissions

I recently went to a meeting hosted by Carbon Neutral Cambridge on developing a Local Transport Plan that would get us towards being carbon neutral.

Quick summary: the measures proposed by local authorities (specifically Cambridge, but I suspect it's not that different elsewhere) won't get us even close to being carbon neutral by 2050, and likely not ever.

Given that, realistically, any hope we have of preventing the worst consequences of climate change means that we need to be carbon neutral by 2030, this is somewhat disappointing.

There was then an analysis of a fairly radical scenario, and even that struggled to just about reach carbon neutrality by 2050.

And, what's worse, both scenarios were pretty optimistic in terms of timescale and takeup of technology. The likelihood is that there will be dithering and delays, pushing it back even further.

(And there's the incorrect assumption that switching to electric vehicles will reduce carbon emissions. On its own, it won't, it requires the world to move far faster to renewables or nuclear than we are right now.)

The other thing that isn't immediately obvious is that, right now, the carbon footprint of moving people about is the same as that for moving goods about. You have to solve both.

We then broke up into focus groups. I hate this (it's just me) - the chances are that either nobody will have anything to say so you spend the time twiddling your thumbs, or there's so much you don't even scratch the surface. On this occasion, we didn't even really get started. It's a huge topic.

But our group (although we did have Peter Dawe sidetrack us with his CitiPod) thought about a couple of priority areas:
  • For people: reduce the need to travel, and the use of remote working
  • For goods: move long distance traffic to rail, and have local distribution hubs
What is clear, though, is that we need significant modal shift from current transport systems to more energy efficient ones. Yes, this means getting rid of cars in their current form. Difficult, given the rather dire state of public transport and the lack of investment in it (although they can always find a few billion to build roads to induce extra demand and cause more congestion and pollution), but necessary.

Friday, December 06, 2019

The effect of passenger boarding on bus services

We all know the saying "you wait ages for a bus, and them 3 arrive at once". But why is this?

The basic reason is simple: once a bus starts to run late, there are likely to be more passengers waiting at stops, slowing it down. Because it's running late, the bus behind it has fewer passengers waiting when it gets to stops, and catches it up. There's a strong feedback loop that drives well-separated buses further apart, and closely separated buses get pushed together.

As a passenger, I noted the characteristics of a number of journeys I took over the summer. These were during the day, so avoid the rush hour.

Very roughly, what I see is that on a 24 minute journey between home and the centre of Cambridge, we spend typically:

  • 12 min actually moving
  • 6 minutes boarding
  • 5 minutes stopped due to traffic/lights
  • 1 minute unboarding

This doesn't account for the unboarding at my destination stop (terminus).

The boarding is much higher than unboarding for the simple reason that you just get off. When you board, you have to pay, show your ticket, or may have queries.

What was also true was that the distribution of boarding times isn't simple. The majority of passengers board quickly in the 10-20s range (there are two peaks, those who've prepaid and are just showing their card or ticket, and a somewhat slower group who have to pay). However, there's a long tail: a small number of passengers have much longer than average boarding times. I've seen some take several minutes - maybe they don't know where they're going, they don't have the right change, they don't understand the system.

The traffic lights are also rather variable. If you get caught by the lights, you can get a wait of several minutes. (The junction at the Catholic church in Cambridge in particular can cause large delays.)

Unlike a train, which pulls into a station, opens its doors for a fixed time, and then goes, a bus stops as long as necessary to let its passengers on or off. This, coupled with the traffic delays, means that wait times are highly variable.

This also means that the predicted arrival times as shown on bus stops by the real time traffic displays simply can't be terribly accurate.




I knocked up a quick model of my bus journey with the observed distribution of boarding and wait times, and (as expected) it comes back with results that aren't dissimilar to the characteristics of actual journeys:
  • Just allowing for the fact that the number of passengers on the journey is random gives a variance of +/- 3 minutes
  • Allowing for the feedback of delays early in the journey causing longer queues later gives a variance of +/- 4 minutes
  • Allowing for the previous bus as well gives a variance of +/- 5 minutes
Given this variability, it's hardly surprising that adherence to the bus timetable is notional at best.

One way to deal with this is to add waits to bring the bus back in line with the timetable. (You have to add waits, you can't remove time unless you have a time machine.) And my 24-minute journey is allowed 30 minutes, so we routinely stop 2 or 3 places along the route. But having to build in this extra wait time is pure waste.

What you can also see is that if the bus were to be full (in other words, taking on 60 people) then it's not entirely unreasonable to require 15 minutes for everyone to board. Those who have stood in a queue in the city centre on a busy evening or a Saturday afternoon will have seen the buses stationary at the stop for this sort of time. Even with the slop in the schedule, it's almost impossible to keep to the timetable if the bus is full. (Especially as those tend to be times when the roads are more congested.)

What if you could reduce boarding time? This gives you a double win: less boarding time makes the journey quicker, but also gives less variability, so you need to build in less slop. It's better for passengers, who get quicker and more reliable journeys, and it's better for the bus operators who make much better utilization of their buses and drivers.

Looking at my journey just to be specific, optimization of loading could almost halve journey times and double efficiency. At busy times on short routes having a second staff member check tickets - rather than forcing the driver to do so - is obviously a win. (This doesn't have to be a conductor, who would check or sell tickets while the bus is moving after everyone has boarded. It could be an inspector at certain stops who validates tickets of those in the queue. When I was living in Toronto some of the busier bus stops were closed interchanges, you paid as you entered the system and didn't need to be checked at the point of boarding at all.)

Eliminating charges entirely would have a similar effect. People just walk on without having to stop. Again, the system is far more efficient as a result.

One of the other minor issues with buses in Cambridge is only having one door. Those wishing to board have to wait for everyone who wants to get off to do so; many other systems have separate doors allowing boarding and unboarding to operate in parallel.

The actual process of issuing tickets has improved, I think. Smart cards and contactless payments are much quicker than the old cash and paper tickets.

But what's interesting here is that improving the efficiency with which passengers board a bus does have the potential to significantly improve journey times, reliability, and the efficiency of the bus system.

Sunday, March 31, 2019

Brexit isn't S.M.A.R.T.

If you've been through an annual performance evaluation in a large company, chances are the HR department has introduced you to the notion of setting SMART goals.

For those unfamiliar with this horror, a SMART goal is:
  • Specific - you have to avoid meaningless waffle
  • Measurable - otherwise how can you prove you've achieved it
  • Attainable - there's no point trying to do something impossible
  • Relevant - the goal must match a requirement
  • Timely - you have to be able to achieve the goal within the reporting period
How does Brexit stack up against the S.M.A.R.T. scheme?

  • Specific - Brexit is vague, undefined, or has multiple definition, possibly meaning something different to every Brexit supporter. Characterized by the vacuous slogan 'Brexit means Brexit'.
  • Measurable - fails again, largely because you can't measure something that isn't even defined. But on any objective measure, Brexit fails on every single measurable test - it won't bring more sovereignty, it won't bring more trade, it won't make us richer
  • Attainable - again, you can't attain something that isn't defined, but looking at most of the individual options for Brexit, most are simply outright impossible - they're simply incompatible with international law, or violate various UK or EU treaties
  • Relevant - for most of the individual issues that people claim to be concerned about, Brexit is an irrelevance, it's UK government policy that's the cause of the problem, not EU membership
  • Timely - claims that we would have all our trade deals rolled over and ready to go have proven false, the reality has proved that any form of Brexit is neither easy nor quick, and if we go ahead with it it's going to tie up and paralyze UK politics for a decade or more
Of course, apart from being vague and unspecified, Brexit also suffers from the fundamental problem that it shouldn't be considered as an objective in its own right - Brexit isn't something you should aim to achieve, it's rather a process by which other objectives are achieved. And when you look at those other objectives - such as sovereignty, prosperity, trade, immigration - it's clear that Brexit is at best irrelevant and most likely plain incompatible with achieving those goals.

Brexit just isn't the S.M.A.R.T. thing to do.

Saturday, November 25, 2017

Left hand Park, right hand Ride

There's been a lot of controversy in Cambridge over the parking charge for our Park and Ride service.

A few years ago, the council introduced a car parking charge. To say it didn't go down well is a bit of an understatement. Locals were outraged, not only by the charge, but the pain and complexity involved in paying for it.

Recently, a plan has come about whereby the charge would be scrapped. Essentially, the Greater Cambridge Partnership would use some of its funds to ensure Cambridgeshire County Council wouldn't take such a financial hit if the charge was removed.

Now, I'm opposed to the charge, but I'm not convinced by the solution.

I regard the charge a a symptom of the dysfunctional transport system we have around Cambridge. For background, consider this Venn diagram from Edward Leigh of Smarter Cambridge Transport:

Let's be clear. That's the abridged version. It doesn't include parish councils, MPs, national government, transport operators, or many other interested parties.

Looking at the structure, is it any surprise that our transport is an inconsistent and disorganized mess? There's no evidence of joined up thinking, and essentially every transport project is a point solution blind to the wider picture.

To my mind, the parking charge is evidence of this disconnect. It shows that rather than running a Park and Ride system, we have some car parks run by the council, and a completely separate bus service run by the bus companies. That the buses actually stop at the car parks is a fortunate coincidence; the whole thing isn't part of a coherent plan.

It gets worse, as the Park and Ride system is distinct from the general bus service. Special buses, special routes, special tickets. Again, an isolated point solution that isn't run as part of a larger plan.

So while I agree that the charge is bad, I also strongly agree with Edward Leigh when he asks whether subsidising parking is the best use of £1.1m? (It's not. You're subsidising cars and a private bus company.)

So what is the answer? Ultimately, you need to get the system sorted out. We need a coherent transport infrastructure rather than everyone pulling in different directions.

To the specifics of the charge, the pain point is paying twice. It's not the direct cost, it's the extra hassle. So pay once. Either have free parking and have the bus ticket cover the cost, or pay to park and make the bus free.

A deeper question is whether the Park and Ride system is actually useful and whether alternatives such as Travel Hubs might work better; or whether it might actually make sense to run bus services to where people live so they don't have to drive at all.

But my bigger concern about the discussion of parking charges is not just that it's leading to bad answers, but that in looking at it in isolation we're ignoring the fact that we're answering the wrong question.