Showing posts with label Transportation. Show all posts
Showing posts with label Transportation. Show all posts

Tuesday, February 11, 2014

What I learned from a sabbatical year

I spent 2013 'overlanding' through South America with my partner. 1 year, 1 continent, 1 simple car, 2 people, 13 countries, 40,000 km. After moving from Canada to the UK 5 years ago, and setting up a new life there, we gave up our jobs, salary, friends and all the comforts of life in one of the greatest metropolis in the world. A lot to let go, but we gained so much more.

Above all, I learned how little I need to live on to be happy, material-wise. We converted the back of our little van into a bed, so we slept in it a lot of the nights. Wild camping at some bizarre and cool spots, like 24-hour gas stations and garages, road-side somewhere in the country, cliff edge by the sea, a lot of central plazas and town squares, in front of police stations (with permission), and once within a secure military compound. The living was rough, and it took some getting used to. I had very few possessions; I was happy; and my eyes were filled with wondrous things throughout the year.

Communities kick ass in supporting overlanding travellers of all modes, by car, motorcycle, bicycle, uni-cycle or even by donkey(!). A few hundred people gathered on a Facebook group were the best near real-time information providers. Almost all overlanders are super eager to share information with each other and help, because we've all known a few hard moments on the road. Most people have never met each other in the cyber community, but are ready to answer questions when asked.

One can have too much of a good thing. I love travelling, and still do. 60+ countries later, my imaginary list is still quite long. Doing a year of pure travel is super fortunate, and I almost don't dare to utter that sometimes I found it hard to drag myself for the 11th time in 3 months to drive through yet another beautiful wine country with breath-taking alpine scenery, or more Andean mountain villages, or serene beaches... etc.. Managing the trip is a huge challenge, but I also missed work a lot, missing the other challenges. So, in the evenings I:
  • brushed up on R and some Machine Learning techniques through Coursera (awesome!)
  • learned something new, OctavePython, more Machine Learning techniques
  • read a lot of blogs on ORanalytics and data science
  • wrote a few blog articles here (definitely neglected when I was working a busy job)
  • thought long and hard about what I want to do when I get back

A bunch of random stuff I learned a bit about:
  • Navigating in places I've never been before. "Don't listen to the British lady (aka the GPS voice), she's never been to Venezuela", and she's leading us down a dead-end.
  • Spotting and dodging potholes, rocks, livestock, cowboys, donkey carts, tree stumps, burned tires (12 day riot aftermath), flying fallen ladder (kid you not from the truck 15m in front at 90km/hr), alignment-breaking and bottom-scraping grooves in the road from heavy Brazilian trucks ... ...
  • Making it Swimming through potholes the size of a swimming pool, with muddy and seemingly endless bottoms, with a 2x4 car that had 6" clearance (nope, didn't get stuck even once! 4x4 is not a necessity for everyone)
  • Fixing cars and dealing with mechanics, and their other-worldly Spanish
  • Playing with the police to always avoid paying bribes (wasn't too often)
  • Finding out just how friendly people are (lots of home-stay invites)
  • Playing the Quena (Andean flute) is way harder than it seems - sticking with my uke instead
  • Optimising the journey in Travelling Sales Man fashion (had to return to the origin to sell the car) - yes, Operations Research is useful in every walk, or drive, of life
  • Optimising decisions under uncertain conditions
  • And of course, learning Spanish, with all sorts of accents and idioms, and the 13 countries' history, culture, landscape, food and people (P.S. mechanics and old country farmers are really hard to understand)

Having finished the year-long journey over a month ago, I was inspired to write this article after reading "Why I put my company on a year-long sabbatical". This is not a PR article, but one to say that anyone can do this sabbatical thing, and you will learn a ton. You don't need the best car all decked out. You don't need to be young. You don't need to be retired. You don't need to be without kids (met a lot of families, with kids from 6-months to 17-year olds). You don't need to have a partner. You don't need to be rich (our all-in costs: £10,000 per person, assuming 2 people sharing). Actually, you will learn how little you need at all. All you need is a bit of discipline to save some money, a bit of gut to throw yourself at it, some luck and common sense to be safe, and a lot of curiosity to explore.

In case you are inspired to consider a sabbatical year, here are some great overlanding resources:

2014 is going to be great. I am never more ready.
First step, land an awesome job.

Sunday, July 31, 2011

An Alternative Way to Fly (as long as expectations are managed)

The purpose of this post is to share the discovery of an alternative way of operating an airline (flight schedule and route wise).

No matter how airlines degrade their service standards these days in the West, I think it's fair to say that most of us still believe that most airlines *intend* to:
  • Take off on-time
  • Land on-time
  • Fly us from A to B as the ticket says, without surprise stops
  • (Oh, and have toilets, of course)

On a recent trip to Ethiopia, we have been shown a rather different way of operating an airline. It contradicts with all of the above, but it works. We took 4 internal flights.

Here is how we experienced them first hand:
  • 1 left on time as per the ticket, and even got us there early (bonus!), because...
  • None of the 4 flights flew the original path it said it would: stopovers were skipped to go direct instead, or the direct flights got stopovers added onto it last minute
  • None of them arrived late, because...
  • Some of them took off earlier than stated
  • Additionally, the air stewardesses were lovely, and they gave passengers snacks and drinks (*gasp* what novelty!)
  • To their credit, they did try to inform passengers of the changes a couple of days ahead of the flight (in our case by email, which we only read after we got back to London).
  • They also tell passengers to double check the flight times a couple of days before, to be aware of any late changes.
(For your curiosity: the international flights from London to Addis Ababa was quite standard. The only oddity was that they weighed everyone's carry-on luggage at the gate, because it's apparently a popular flight to take lots of stuff with you!)

IMHO, an airline would play this game, because: (we suspect - unconfirmed)
  • It wants to minimise costs - mainly fuel in this case.
  • It has 1-2 planes that fly in circles to cover off a handful of popular destinations.
  • As the airline gets more and more requests for seats through the form of purchased tickets, it is faced with an optimisation problem to fly all its customers to their expressed destinations with minimum cost. The best way to do this is probably through re-shuffling the schedule. For instance, if a plane is hopping from A to B to C in sequence, where B is closer to A than C is, and if we discover 2 days before the flight that the plane is filled with 2/3 passengers going to C, and 1/3 going to B, then flying A->C->B is cheaper than A->B->C. What if there are customers wishing to go from B to C? We hear that the airline is known for cancelling flights as well. Luckily, we didn't experience this.
This way of operating an airline is possible, because:
  • It is a monopoly.
  • The number of flights are few, so it's easy to manage change.
  • Customers expect it and adjust flying behaviour accordingly (i.e. always check the flight times before the day of flight, and always leave wiggle room before and after the flight).
  • For foreigners who are used to the typical western airline service (i.e. expect it to take-off and land on-time and fly the route it says it would), the price justifies it and shuts people up from complaining, and instead people will have a laugh (or write a blog post!) about it.
  • It doesn't call itself "Precision Airline" (the Tanzanian airline), and can afford to deviate a little. 8-)
P.S. If you are planning to visit Ethiopia, and intend to fly within the country, you may want to consider buying the tickets within the country rather than online. It is significantly cheaper due to price control. This is true as of spring 2011, so double check this before you travel.

Wednesday, October 13, 2010

Oyster Card Optimisation

Transportation is an industry where a lot of Operations Research is practiced. In the following article I would like to share an example of optimisation that I have noticed in the fare pricing system on the London Underground.

Public transportation in London, England has a convenient and efficient means of collecting fares from travellers. Introduced back in 2003, the Oyster Card is the size of a credit card and is pre-loaded with money by the traveller. On each trip they take, the traveller touches the oyster card to a reader, registering their journey with the system which deducts payment from their balance. Each single journey is charged at a different rate depending on the origin zone, destination zone, and time of day.

A daily capping system is in place such that you will never pay, in a day, more than the price of a day-pass covering all of your journeys for the day. For example, in a day where you only travel in zone 1 off-peak your journeys will cost £1.80, £1.80, £1.80, £0.20, £0, £0 and each journey after that is free, as you essentially now have a day-pass on your card when your daily cap has reach at £1.80*3 + £0.20 = £5.60.

A Canadian friend of mine, currently residing in Australia, visited me here in London the other weekend. Knowing the ease, convenience, and price-capping guarantee, I recommended that he get an Oyster Card. He loaded it up with £10 at Heathrow and came into town to drop his bags at my place. After a short jet-lag nap he headed out into the core to see the tourist sights, travelling frequently on the underground. At the end of the day he reported that his Oyster Card credit had run out and that he had needed to top up the balance. This surprised me, so we worked out his journeys and payments:
  • Zone 6 (Heathrow) to Zone 1 at Peak - £4.20
  • 6 x Zone 1 Off-Peak - £1.80 each

Because he travelled from Zone 6 to Zone 1 at peak, his cap for the day was £14.80 even though had he bought a Zone 1 day-pass at Heathrow he would have only paid £5.60 + £4.20 = £9.80. So the Oyster Card is convenient and comes with a price capping system, but there are holes in that system. In this case it cost him £5.00 which is about an hours work at minimum wage in the UK, so not trivial.

Any individual travelling on a public transportation network wants to perform an optimisation. In this case, they want to minimize their total cost by selecting the most efficient combination of fares to cover all of their journeys. This problem presents itself as a classic optimization problem; Subject to constraints, like the requirement to purchase tickets to cover all journeys, the goal is to minimize total cost, a function of the decisions to buy tickets. An optimisation problem like this can be formulated mathematically and solved by computers using a discipline called integer programming, one of the tools in the Operations Research practitioner's toolbox.

If this problem can be solved by computers, why doesn't the Oyster Card system provide a lowest price guarantee rather than the evidently imperfect price-capping system? Consider for a moment the requirements of the system:
  • Daily ridership of around 3 million
  • At the end of their journey, users must be told almost instantaneously what the cost was and what their remaining balance is

Optimisation problems of this nature are not always fast, easy, or even possible to solve optimally. The computers of today are fast, but there's plenty still beyond them. The tube system isn't even using the latest technology. I've been told that some Underground components still use punch cards! Every time a customer makes a journey this optimisation must be calculated and that must be done 3 million times a day and that is unfortunately too much.

When an optimisation problem is too big or too complex to solve directly and perfectly, analysts use something called heuristics to come up with near-optimal solutions. There are commonly used methods, but depending on the problem, customised heuristics can be developed, using the unique structure of the problem in question to produce a near-optimal result. That is exactly what the price capping system is; It is a heuristic used to make a good approximation of the lowest price.

There are effectively only two types of tickets in the system: single tickets and day passes. Day passes are the only way to save money. It is rarely worthwhile buying two separate day passes. It follows naturally that a simple rule of thumb for cost optimisation is to compare your daily total of single trips to the price of a day pass covering all those journeys and choose the lower option. The conditions that I list at the start of this paragraph are essential consequences of the structure of the problem, and we can exploit them to arrive at our simple heuristic, the same one that the oyster cards use.

In a future article I hope to look into formulating the optimisation problem of the London Underground and consider alternative heuristics.