Making postal collections

Something curious happened towards the end of 2014.  We are fortunate that there is a letter box at the end of our road, about 100 metres from our house.  For non-UK readers, mail is collected by Royal Mail vans from letter boxes, taken to a central sorting office and sent to its destination.  Letter boxes are emptied at some time every day except Sundays.  There is a sheet on the front of the box to indicate the time when the box will be emptied.

Until quite recently, "our" box was emptied (according to the sheet on the front) at 6:30pm daily, except for Saturdays when it was emptied at 12:30pm.  Then, the sheet was changed.  It now reads 9:00am daily and 7:00am on Saturdays.  This sudden change caught us by surprise.  A note on the sheet says that there is a later daily collection at our hospital, about ten minutes' walk away, at 4pm.  There is a general caveat that the box may be emptied later than these times.

We looked at another letter box nearby; its sheet had been changed in the same way.  So I went onto the Royal Mail website and discovered that this has been part of a nationwide change of procedure.  Mail in the UK is now going to be collected from many letter boxes at the same time as it is delivered in local roads.  In other words, the vehicle used for delivering the mail will also take mail away from the boxes where this change has occurred.  This was normal practice for many rural letterboxes - and often people in the countryside would leave their mail at the door for the deliveryman (postman in the UK) to take away, though this was never official procedure. 

The website went on to explain that letter boxes such as the two that we looked at have been judged to have low usage.  Across the country, all such boxes will now be emptied by the delivery vehicle.  This will save costs, but I doubt whether the price of mail will fall as a result.  The website also mentioned a survey of users of the mail who were content with such a change. 

It looks as if there has been some O.R. modelling here.  Someone has looked at the marginal cost of collecting mail from a box which only has a small number of letters and asked the question "What if? ... What if we did away with that box in the late collection?"  And the conclusion is that sending one vehicle to the letter box near my house during the day is cheaper than sending two. 

Now, what about the user's perspective?  Only a very few of the letters that I send in the 21st century are time critical.  Nearly all of them can be prepared and posted one day earlier than would have been my practice before the change.  And that is probably true for most of the people who use that letter box.  However, I may need - occasionally - to write a letter and post it the same day so as to be in the mail by the evening.  And here is where the O.R. has slipped up.  The letter box at the hospital is probably the nearest to me with an afternoon collection, but it is not the most convenient to use.  The "What if?" study hasn't fully explored the "What will users do if they want to catch an afternoon  collection?"  They will not necessarily go to the closest letter box with such a collection; they will probably behave in a different way.  And for the local letter box, they will go:
 (1) where they can park easily (the hospital car park is generally very full, there are high parking charges, and the area is patrolled so that the risk of being fined for parking without paying the charge is quite high);
(2) where they can combine posting mail with another errand, e.g. shopping.  (I don't need to go to the hospital at the same time as posting mail)

So, dear friends doing O.R. for Royal Mail, when the sheets of collection times are being prepared, ask postmen with local knowledge about the accessibility and advantages of several local letter boxes, and list more than one on the information sheet.  After all, O.R. is not just about the mathematics of vehicle routing, not just about the economics and costing of a scheme, not just about statistics of performance, but also about the psychology and behaviour of all those affected. 


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