Using technology to reduce queues

Long lines at check out can spoil a shopping trip just as a bad dessert can spoil an otherwise fine dinner. Either can, if you will, leave a bad taste in your mouth. So what can a retailer do besides throw (expensive) bodies at the problem?

As the Wall Street Journal tells it, there are quite a few options. A recent article discussed process changes and new technologies different firms are using to try and reduce customer waits (Retailers Wage War Against Long Lines, May 2). The most interesting to my mind was what supermarket chain Kroger is trying.

Supermarket giant Kroger Co. is winning the war against lengthy checkout lines with a powerful weapon: infrared cameras long used by the military and law-enforcement to track people.

These cameras, which detect body heat, sit at the entrances and above cash registers at most of Kroger’s roughly 2,400 stores. Paired with in-house software that determines the number of lanes that need to be open, the technology has reduced the customer’s average wait time to 26 seconds. That compares with an average of four minutes before Kroger began installing the cameras in 2010.

“The technology enabled us to execute at the front of the store without that additional (labor) expense,” said Marnette Perry, senior vice president of retail operations for Kroger.”It’s remarkable that we’ve been able to improve execution as much as we have without a big price tag.” …

The system includes software developed by Kroger’s IT department that predicts for each store how long those customers spend shopping based on the day and time. The system determines the number of lanes that need to be open in 30-minute increments, and displays the information on monitors above the lanes so supervisors can deploy cashiers accordingly.

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Charging queues

Automotive News recently had a report on driving a Tesla Model S electric car from Los Angeles to Las Vegas. You can find a video describing the drive here. What I found more interesting was the reporter’s description of stopping to charge up the car (A flaw in Tesla’s plan: It’s Chargie McVanish, Apr 8). In order to spur interest in its vehicles, Tesla is building out a network of solar-powered Supercharger charging stations. Their website says they currently have nine but plan to get to one hundred by 2015. One is in Barstow, perfectly positioned for a drive from LA to Vegas.

So what’s a reasonable wait to charge your Tesla?

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Waits at the Beijing airport

All this week I have been traveling in China with a group of Kellogg faculty. It has been a fascinating trip as we have met with officials from several government agencies, executives from a variety of companies, and colleagues from the Guanghua School of Management. I have never been to China before so I have been trying to take everything in as we have gone around Beijing and Shanghai. This sign caught my eye as we were going through the Beijing airport.
I like the way they have chosen to present the wait time information for clearing security. It got me wondering why American airports don’t try reporting similar information. If nothing else, being clear about the targets would help set expectations for how long passengers should expect to be in queue. Of course, in the US, the people running the airport do not control how TSA agents are scheduled. Nor do they determine how many officers are managing the immigration desks (another piece of data on the sign).

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Domino’s in India: Meeting deadlines by turning away business

My colleague Sunil pointed me a neat article on Domino’s Pizza’s Indian operations.  While the chain long ago gave up on an explicit delivery time guarantee, their Indian franchisee Jubilant Foodworks still promises 30 minutes or the pie is free. That is not an easy promise to keep in, for example, an old neighborhood with streets running every which way and no really good maps. Still they manage to hit the thirty minute target remarkably often despite not having a whole of lot time for the actual delivery part of the process (Domino’s deadline to deliver, Financial Times, Jan 17).

With preparation, baking and boxing of pizzas taking 12-13 minutes, Indian deliverymen have 8-10 minutes to ferry their piping hot cargo to its destination – leaving a margin of just a few minutes. Riders cannot race to their destinations either: their motorbikes are modified to restrict their maximum speed to 45kph. That means riders must know every street, pothole, traffic light, choke point, construction site and police roadblock in their sectors of fast-changing, densely populated cities. …

Of all Domino’s deliveries in India, less than 0.5 per cent take more than 30 minutes to reach the consumer. Top managers monitor every store’s late rate closely. Rising pizza giveaways are seen as an indicator that a store is being overwhelmed by rapidly growing business – and that the area may be ripe for an additional outlet – or that local congestion is worsening considerably. “We watch that number like hawks,” Mr Kaul says.

Now there are obviously several steps in making these deliveries happen — from making sure that the kitchen staff is well-trained to scheduling enough delivery drivers. The most interesting part to my mind is the last thing hinted at in the quote above: How does Domino’s think about locating stores — and defining their service areas — so they can hit their delivery window?

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Controlling queues with even-odd rationing

Here at the Operations Room, we love queues and few queues have gotten as much attention lately as the lines of drivers waiting to buy gasoline in New Jersey and New York following the hurricane. Stories abounded about wasted time and why allowing price gouging would actually be good. Of course, neither states cleared station owners to jack prices up. Instead, they implemented Nixonian rationing based on license plate numbers. Those with plated ending in even numbers got to buy on even days and those with odd numbers got to buy on odd days.

Now, the Numbers Guy column and blog at the Wall Street Journal is asking whether it worked (Fuel Rationing Is Hard to Gauge, Nov 16, and Does Odd-Even Rationing Work?, Nov 17). Turns out there is no clean answer on this. On the one hand, studies of when similar schemes were used in the early 70s claim to show they were ineffective but even those studies authors think this time may have been different.

“I’m not sure our analysis transfers directly to the Sandy shortage situation,” said Robert Goldfarb, an economist at George Washington University in Washington, D.C. In a 1983 paper, Prof. Goldfarb and co-authors found the odd-even rationing system could lengthen waits, because people who normally spaced out refills by an odd number of days—say, five days—might move up their regular refills to every four days to avoid running out.

William Huss, co-author of a 1981 paper with a similar conclusion, added that while his model “has a solid mathematical foundation, its assumptions regarding driver behavior are hypothetical and logical but not necessarily based on psychological research.”

I have to admit that I love that last quote since it could equally apply to every paper I have written. 

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The Complexity of Managing the Deceased-Donor Kidney Allocation System

The NY Times (“In Discarding of Kidneys, System Reveals Its Flaws“) had an interesting article on one of the main issues of Kidney allocation:

 Last year, 4,720 people died while waiting for kidney transplants in the United States. And yet, as in each of the last five years, more than 2,600 kidneys were recovered from deceased donors and then discarded without being transplanted, government data show.

The question is why. One may conclude that the system is just inefficient, yet a closer look reveals that this inefficiency is rooted in many important principles, regulations, and incentives, all while attempting to create a fair system.  In order to better understand the issues, we need to understand how kidneys are being allocated in the US: The country is divided into 58 districts. When a kidney of a deceased person becomes available, the system allocates it to the person with the highest priority within that region. This priority is a function of the waiting time, whether a recipient is a child or not, as well as other factors. The system does not consider the projected life expectancy of the recipient or the urgency of the transplant. The allocation is initially local, and only when there is no match, the search expands to other regions. All of that is done while competing against the clock: Kidneys start to degrade after 24-36 hours.  The system is allowed to make offers to only a limited set of hospitals at any point in time, and these, in turn, have an hour to respond.

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The gratuitous iPhone 5 post: Charging to stand in Apple’s queue

In case you have been living under a rock, Apple is releasing a new iPhone and if you stop by an Apple store this Friday you can get one. That is, of course, if you get there early enough. For most releases of new Apple gadgets people line up early and often in order to have the newest device a week before their neighbor. But waiting is a hassle. Or, perhaps, a market opportunity (TaskRabbit: We’ll sell ya a spot in the iPhone 5 line, CNET, Sep 13):

San Francisco-based TaskRabbit has rolled out a new program that lets people in the San Francisco Bay Area, as well as New York, purchase four hours worth of wait time in line at an Apple retail store for $55. That’s more than a quarter of the price of Apple’s entry-level iPhone 5, and $55 more than it costs to pre-order the phone from Apple’s Web site and carrier partners.

Surrogate waiting is by no means a new thing. What kind of neat here is that it is being intermediated on (potentially) a large-scale by a “distributed workforce” company.

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Making fast food faster

How does a quick service chain increase sales when it’s tough to raise price or open new outlets? Process improvements! Or at least that is what the Wall Street Journal says (Restaurant Chains Feel the Need for Speed, Aug 29). The argument is that long lines scare off customers — especially at peak times — so faster  fast food means more sales.

Here’s what they say about Chipotle:

For Chipotle, it’s a top priority. “We’ve come a long way, but there’s still a long line, and there’s people turning away at the end,” said Co-Chief Executive Monty Moran.

Chipotle processed an average of six more transactions during the lunch hour last quarter, beating its 2007 record. The Colorado-based burrito chain is training its staff to be more prepared for the lunch rush, with extra trays of ingredients ready on the sideline, and to be attentive to customers so they don’t have to repeat themselves.

At each of its most efficient restaurants, Chipotle averages more than 350 transactions during the lunch hour—about one every 11 seconds.

A customer every 11 seconds is pretty impressive and certainly faster than I would have expected. Note that Chipotle’s approach makes sense since their service is very much human paced as orders are filled by scooping fillings and rolling burritos. The article reports that they have tried having a second register but found it generally made no difference. That they even tried that makes me wonder if whoever proposed that has ever eaten at a Chipotle since payment is clearly not the bottleneck.

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The ethics of jumping the queue

I must admit that I am generally not a fan of the New York Times Magazine’s The Ethicist column. Often the letters hover between whining and  overly specialized or the response is too preachy but this week there was a very intriguing question (Impatience Takes a Number, Aug 26).

Returning my cable box at the Time Warner store, I arrived to find 30 people ahead of me in line. Begrudgingly, I took a number (as you do at the deli counter) and waited. A woman turned around and told me she could no longer stay. She offered me her ticket, five numbers away from being called. At first I said no — it wouldn’t be fair to everyone else who was waiting — but she insisted. I took her ticket, returned my cable box and walked out of the store while everyone else kept waiting. Was it right to take the ticket? ALEXANDRA, NEW YORK CITY

So that’s just a great discussion starter. This is not merely about line cutting, which is flat-out rude and we all know is wrong (although, as Gady has proven, it may not only be socially efficient — it can be supported in equilibrium!). The letter writer is not setting  out to beat the system; she is being gifted a chance to discreetly shorten her wait.

What makes this even more interesting is that just last week, the same newspaper ran an essay emphasizing that what really matters in queuing systems is fairness (Why Waiting Is Torture, Aug 19).

Perhaps the biggest influence on our feelings about lines, though, has to do with our perception of fairness. When it comes to lines, the universally acknowledged standard is first come first served: any deviation is, to most, a mark of iniquity and can lead to violent queue rage. Last month a man was stabbed at a Maryland post office by a fellow customer who mistakenly thought he’d cut in line. Professor Larson calls these unwelcome intrusions “slips” and “skips.”

The demand for fairness extends beyond mere self-interest. Like any social system, lines are governed by an implicit set of norms that transcend the individual. A study of fans in line for U2 tickets found that people are just as upset by slips and skips that occur behind them, and thus don’t lengthen their wait, as they are by those in front of them.

So what is the right answer here?

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Running supermarket checkout with a single queue

Way back in the early days of this blog, Gady had a post about queuing innovations at Hannaford Supermarkets, a regional chain of markets serving the Northeast. One of things Gady mentioned was that they were experimenting with having a single line for those waiting to checkout. Having now visited Hannaford’s relatively new store in West Lebanon, NH, I can show you what that looks like:

As Gad’s original post notes, a single checkout line is not a completely new idea for supermarkets. Indeed, Wholefoods’ Columbus Circle store has gotten all sorts of press for its single queue system. I would argue that this is a little bit different. At Wholefoods, a single queue is as much about packing many, many registers into a tight space as it is about efficiently moving customers through. That’s not really true in West Lebanon; this is pretty much your standard, large, suburban American grocery store. In West Leb, a single queue is — as the signs suggest — all about reducing customer waiting times.

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