5 ms·

Why UPS drivers don't turn left and you probably shouldn't either

33 points by Anon84 6y ago

robert_foss 6y ago
(in the North America, where you can turn right at will)
- dredmorbius 6y ago
  Generalised: avoid cross-trafic turns.
  - nraynaud 6y ago
    well, in the old world nothing is perpendicular, and all the roads have a different width and single direction without any clear pattern, so not getting lost is already a strong goal, there is very limited BW to optimize for time :)
Jemaclus 6y ago
This is anecdotal, but I've asked about twenty or so UPS drivers that I've met over the years whether they avoid turning left or not, and they all just laugh and say "No, that's dumb." Either they're messing with me, they just aren't following "the rules", this "UPS drivers don't turn left" thing is urban legend. I'm kind of leaning toward the latter. Not so much that it never happened, but more that it was something that some data scientist said was a good idea, but never actually works I practice, and so UPS drivers don't actually follow this. Maybe it's a policy. I don't know. I don't have a list of UPS policies handy at the moment. But of the (admittedly small) sample size I've discussed it with, every single one says they do not follow that policy, or is it something they were instructed to do. Which makes me kind of roll my eyes whenever I see these articles or podcasts or what-have-you. They pop up fairly frequently, but... it feels more like clever marketing by UPS than an actual policy.
- bigbubba 6y ago
  Maybe UPS drivers ignore it, or maybe UPS no longer does it, but it's not an urban legend: https://www.ups.com/us/en/services/knowledge-center/article.page?kid=aa3710c2 https://www.ups.com/us/en/services/knowledge-center/article.... (This link claims they had 55,000 drivers using the system in 2016.)
  - Jemaclus 6y ago
    Fair enough!
- nraynaud 6y ago
  My thinking is that it could be more subtle. (in the US) In very suburban streets in the middle of the day, nobody cares about turning left in an empty street. In more congested and wider streets it could get more delaying. But if the planning has been done by a software before the driver took the truck, the software might have avoided as many left turns as possible without telling the driver, and without having any need to ask the driver to micro-optimize themselves, they just follow the GPS (you probably can't do better), or the most sensical path ca't do better), or do a slight detour to get a snack (unforseeable). Long story short it might be a software policy without being a driver policy, that would be enough to have a significant statistical result, I don't think drivers re-plan their shift.
  - db48x 6y ago
    Exactly, all you have to do is reorder the list of stops to make left turns less necessary. You don't need even tell the drivers about it.
  - garrettgrimsley 6y ago
    >software before the driver took the truck The UPS route-planning system is called ORION. >they just follow the GPS I'd reckon that anyone on a bid route or other route that they are familiar with can do better than what ORION gives us. We aren't taking solely distance into account, that would be far too simple. We're considering other factors too, including hard time constraints like next day air commit times, regularly scheduled pickups, irregular pickups, business hours, and whether we can even physically access the packages [0, 1] that the system wants us to deliver. >I don't think drivers re-plan their shift. We most certainly do, we wouldn't finish the day if we blindly followed trace. [0] https://youtu.be/fMeBkPd8ZJk https://youtu.be/fMeBkPd8ZJk [1] https://youtu.be/Oi4DW04_D5o https://youtu.be/Oi4DW04_D5o
amelius 6y ago
tl;dr: it reduces the chances of an accident and cuts delays caused by waiting for a gap in the traffic, which would also waste fuel.
tomohawk 6y ago
They must have designed the road system in New Jersey - almost no left turns are allowed. Instead, dog legs, roundabouts, and, when there is too much temptation, jersey walls where most states have yellow lines.
jordache 6y ago
UPS drivers turn however they want in my neighborhood. No left turn restrictions.
- bigbubba 6y ago
  As I understand it, their navigation system favors routes with fewer left turns, but there is no prohibition against drivers making left turns.
whalesalad 6y ago
One of my favorite things about living in Michigan is the way we do left turns: https://en.wikipedia.org/wiki/Michigan_left https://en.wikipedia.org/wiki/Michigan_left
ogre_codes 6y ago
This article is a little off base. UPS is solving for "What is the best way to safely deliver packages to 300 addresses". There are a lot of ways to do cover that ground effectively without too much waste. The routes UPS drivers share little resemblance to the way normal people drive. I'm solving for "How do I get to work" or "How to get to the grocery store". I'm taking the highway 80% of the distance, then my work is on the left... do I take 3 right turns to get there circling a potentially large city block? The UPS driver might well have stops on those side streets, I don't. The idea behind this is sound, but it doesn't necessarily apply to the way individuals who aren't driving package routes should drive.
- smaryjerry 6y ago
  Right, you don’t want a delivery driver parking and crossing the street. You want them next to the address, walking less and carrying weight for less time. This is absolutely not applicable to anyone driving in their normal life.
vincent-manis 6y ago
“Never turn left” would be a ridiculous rule on its own, as it ignores the frequency of oncoming traffic, or the existence of left-turn bays (with left-turn signals) or 4-way stop signs.
mattnewport 6y ago
The "prisoner's dilemma" stuff at the end of the article makes no sense. The article starts by explaining why UPS does this - it benefits UPS. UPS doesn't do this to be a "good citizen", it does it because it is more efficient for UPS. UPS doesn't even do it because it's somehow better for UPS overall even though it's worse for individual UPS drivers. If an individual driver could do better by turning left according to their route planning software then it would have them turn left. If this works in general for typical routes driven by individuals (rather than only for delivery routes like a UPS driver is making with multiple stops that don't have to happen in any particular order) then it would make sense for individuals to do it and they could benefit by doing it without needing anyone else to do it as well. There is no prisoner's dilemma here.
syntaxing 6y ago
I always wondered if there’s a dedicated team at UPS of just mechanical engineers (for some reason most process optimization professionals have a MechE degree) and mathematicians just figuring out these sort of problems.
- Jemaclus 6y ago
  I'm sure there are. There's a team at my company (retail, not UPS) whose sole responsibility is figuring out how to optimize getting from Point A to Point B. At least 6 people on the team, probably more involved that I don't realize. At the scale my company and UPS operate in, even minor efficiency gains can add up to gazillions of dollars in savings.
odomojuli 6y ago
I talked to an Uber employee once about a "Zoolander mode" project for drivers so that it only turns right and cannot turn left. The code was pretty simple if you've ever written a maze-solving algorithm. (Hint: What happens if you follow either side of wall for the entire maze?) In theory, this would be useful for truck drivers or prioritizing passenger pickup locations. But now, I use it as an example of overengineering and overoptimization. In practice, the main concern should be reducing cognitive load on the driver. Additional instructions, rules that can be potentially broken, inconsistencies in logic, all of it poses a substantial risk.

33 points by Anon84 6y ago

robert_foss 6y ago

(in the North America, where you can turn right at will)

dredmorbius 6y ago
Generalised: avoid cross-trafic turns.
- nraynaud 6y ago
  well, in the old world nothing is perpendicular, and all the roads have a different width and single direction without any clear pattern, so not getting lost is already a strong goal, there is very limited BW to optimize for time :)

Jemaclus 6y ago

This is anecdotal, but I've asked about twenty or so UPS drivers that I've met over the years whether they avoid turning left or not, and they all just laugh and say "No, that's dumb." Either they're messing with me, they just aren't following "the rules", this "UPS drivers don't turn left" thing is urban legend. I'm kind of leaning toward the latter. Not so much that it never happened, but more that it was something that some data scientist said was a good idea, but never actually works I practice, and so UPS drivers don't actually follow this. Maybe it's a policy. I don't know. I don't have a list of UPS policies handy at the moment. But of the (admittedly small) sample size I've discussed it with, every single one says they do not follow that policy, or is it something they were instructed to do. Which makes me kind of roll my eyes whenever I see these articles or podcasts or what-have-you. They pop up fairly frequently, but... it feels more like clever marketing by UPS than an actual policy.

bigbubba 6y ago
Maybe UPS drivers ignore it, or maybe UPS no longer does it, but it's not an urban legend: https://www.ups.com/us/en/services/knowledge-center/article.page?kid=aa3710c2 https://www.ups.com/us/en/services/knowledge-center/article.... (This link claims they had 55,000 drivers using the system in 2016.)
- Jemaclus 6y ago
  Fair enough!
nraynaud 6y ago
My thinking is that it could be more subtle. (in the US) In very suburban streets in the middle of the day, nobody cares about turning left in an empty street. In more congested and wider streets it could get more delaying. But if the planning has been done by a software before the driver took the truck, the software might have avoided as many left turns as possible without telling the driver, and without having any need to ask the driver to micro-optimize themselves, they just follow the GPS (you probably can't do better), or the most sensical path ca't do better), or do a slight detour to get a snack (unforseeable). Long story short it might be a software policy without being a driver policy, that would be enough to have a significant statistical result, I don't think drivers re-plan their shift.
- db48x 6y ago
  Exactly, all you have to do is reorder the list of stops to make left turns less necessary. You don't need even tell the drivers about it.
- garrettgrimsley 6y ago
  >software before the driver took the truck The UPS route-planning system is called ORION. >they just follow the GPS I'd reckon that anyone on a bid route or other route that they are familiar with can do better than what ORION gives us. We aren't taking solely distance into account, that would be far too simple. We're considering other factors too, including hard time constraints like next day air commit times, regularly scheduled pickups, irregular pickups, business hours, and whether we can even physically access the packages [0, 1] that the system wants us to deliver. >I don't think drivers re-plan their shift. We most certainly do, we wouldn't finish the day if we blindly followed trace. [0] https://youtu.be/fMeBkPd8ZJk https://youtu.be/fMeBkPd8ZJk [1] https://youtu.be/Oi4DW04_D5o https://youtu.be/Oi4DW04_D5o

amelius 6y ago

tl;dr: it reduces the chances of an accident and cuts delays caused by waiting for a gap in the traffic, which would also waste fuel.

tomohawk 6y ago

They must have designed the road system in New Jersey - almost no left turns are allowed. Instead, dog legs, roundabouts, and, when there is too much temptation, jersey walls where most states have yellow lines.

jordache 6y ago

UPS drivers turn however they want in my neighborhood. No left turn restrictions.

bigbubba 6y ago
As I understand it, their navigation system favors routes with fewer left turns, but there is no prohibition against drivers making left turns.

whalesalad 6y ago

One of my favorite things about living in Michigan is the way we do left turns: https://en.wikipedia.org/wiki/Michigan_left https://en.wikipedia.org/wiki/Michigan_left

ogre_codes 6y ago

This article is a little off base. UPS is solving for "What is the best way to safely deliver packages to 300 addresses". There are a lot of ways to do cover that ground effectively without too much waste. The routes UPS drivers share little resemblance to the way normal people drive. I'm solving for "How do I get to work" or "How to get to the grocery store". I'm taking the highway 80% of the distance, then my work is on the left... do I take 3 right turns to get there circling a potentially large city block? The UPS driver might well have stops on those side streets, I don't. The idea behind this is sound, but it doesn't necessarily apply to the way individuals who aren't driving package routes should drive.

smaryjerry 6y ago
Right, you don’t want a delivery driver parking and crossing the street. You want them next to the address, walking less and carrying weight for less time. This is absolutely not applicable to anyone driving in their normal life.

vincent-manis 6y ago

“Never turn left” would be a ridiculous rule on its own, as it ignores the frequency of oncoming traffic, or the existence of left-turn bays (with left-turn signals) or 4-way stop signs.

mattnewport 6y ago

The "prisoner's dilemma" stuff at the end of the article makes no sense. The article starts by explaining why UPS does this - it benefits UPS. UPS doesn't do this to be a "good citizen", it does it because it is more efficient for UPS. UPS doesn't even do it because it's somehow better for UPS overall even though it's worse for individual UPS drivers. If an individual driver could do better by turning left according to their route planning software then it would have them turn left. If this works in general for typical routes driven by individuals (rather than only for delivery routes like a UPS driver is making with multiple stops that don't have to happen in any particular order) then it would make sense for individuals to do it and they could benefit by doing it without needing anyone else to do it as well. There is no prisoner's dilemma here.

syntaxing 6y ago

I always wondered if there’s a dedicated team at UPS of just mechanical engineers (for some reason most process optimization professionals have a MechE degree) and mathematicians just figuring out these sort of problems.

Jemaclus 6y ago
I'm sure there are. There's a team at my company (retail, not UPS) whose sole responsibility is figuring out how to optimize getting from Point A to Point B. At least 6 people on the team, probably more involved that I don't realize. At the scale my company and UPS operate in, even minor efficiency gains can add up to gazillions of dollars in savings.

odomojuli 6y ago

I talked to an Uber employee once about a "Zoolander mode" project for drivers so that it only turns right and cannot turn left. The code was pretty simple if you've ever written a maze-solving algorithm. (Hint: What happens if you follow either side of wall for the entire maze?) In theory, this would be useful for truck drivers or prioritizing passenger pickup locations. But now, I use it as an example of overengineering and overoptimization. In practice, the main concern should be reducing cognitive load on the driver. Additional instructions, rules that can be potentially broken, inconsistencies in logic, all of it poses a substantial risk.