#105 2004 · United Parcel Service (UPS) · Logistics / package deliveryattack-invisible-cost
UPS makes its trucks drive farther on purpose, because turning left costs more than driving extra blocks
the problem
The shortest path on a map isn't the same as the fastest, safest or cheapest path to actually drive
background
Route planning for a delivery fleet naturally optimizes for the shortest driving distance between stops, and turning left across oncoming traffic to reach the next stop on a map is often the shortest path available. The hidden cost of that turn doesn't show up in a distance calculation: a driver waiting in a left-turn lane for a gap in oncoming traffic burns idle fuel, loses time that compounds across dozens of stops a day, and faces a meaningfully higher accident risk than a right turn, since a left turn crosses the path of oncoming vehicles.
UPS runs roughly 55,000 delivery routes a day in the US alone, at a scale where a cost that looks trivial on any single turn — a few dozen seconds idling, a fractional increase in accident risk — compounds into a real operating expense once repeated across an entire fleet's daily mileage. Company accounts describe informal predecessors to a no-left-turn approach going back decades in UPS's loop-dispatch route planning, but the practice wasn't studied, quantified and made formal company policy until UPS began instrumenting its fleet with better vehicle-tracking data in the early 2000s.
the move
UPS formally announced its policy of routing delivery trucks to avoid left-hand turns across oncoming traffic in 2004, after data from its vehicle-tracking systems confirmed that eliminating left turns — even when it meant a truck drove farther and made more right turns to reach the same destination — reduced total fuel burn, idle time and accident exposure enough to outweigh the extra distance. Left turns now make up less than 10% of all turns UPS trucks make.
the payoff
UPS has reported using roughly 10 million fewer gallons of fuel a year as a result of the policy, cutting on the order of 20,000 tonnes of carbon dioxide emissions annually and delivering hundreds of thousands more packages with the fuel and time saved — an estimated $20 million or more in annual fuel-cost savings alone at typical diesel prices, before accounting for the reduction in accident-related costs from avoiding left-turn collisions.
what came after
The no-left-turn policy became one of the most widely cited real-world examples in operations-research and route-optimization teaching of a counterintuitive efficiency gain — a policy that increases distance traveled but decreases total cost — and was later reinforced and extended by UPS's ORION route-optimization software, rolled out fleet-wide by 2016, which validated and refined the same underlying insight algorithmically across the company's full delivery network.
references
- [1]UPS Trucks Don't Turn Left and Neither Should YouTIME, 2017time.com
- [2]'No Left Turns' (self-interested conservation at UPS)MasterResource, 2017masterresource.org