Imagine a driver in Berlin who starts the morning with a list of 40 stops scattered across the city. Each customer is waiting, traffic is mounting, and the dispatcher expects the vehicle back before the end of the shift. The driver knows the sequence of visits will make or break the day.
This deceptively simple question is at the heart of the Travelling Salesman Problem (TSP), one of the most studied puzzles in mathematics and computer science. Born in the 1930s as a theoretical challenge, the TSP has since shaped the way we think about logistics, routing, and supply chain optimization.
A Puzzle Older Than Modern Supply Chain
The Travelling Salesman Problem asks: What is the shortest possible tour that visits each city exactly once and returns to the starting point?
On paper, it looks like a neat brain teaser. In practice, it reveals something deeper: how quickly complexity explodes. With just 10 stops, there are more than 3.6 million possible tours. With 20 stops, there are already more possible routes than there are stars in the universe.
Mathematicians classify the TSP as NP-hard, meaning it is computationally intractable to solve exactly for large instances. Yet that has not deterred researchers. Over decades, they have developed clever algorithms, some that guarantee an optimal solution for smaller problems, others that deliver near-optimal answers fast enough for real-world use.
For the logistics industry, the appeal is obvious. Sequencing matters. And even small improvements, just a few kilometers less in a daily route, scale up to big savings across fleets, warehouses, and networks.
Why the TSP still matters in 2025?
Modern logistics problems rarely look like the textbook TSP. Today’s operations involve: multiple vehicles instead of one, capacity limits, time windows and dynamic conditions.
Over time, researchers have shaped the TSP into many useful variants:
| Variant | Description | Logistics example |
|---|---|---|
| Multiple Salesmen Problem (mTSP) | Several drivers each complete a tour; models how stops are divided among staff. | Assigning delivery routes across a fleet. |
| TSP with Time Windows (TSPTW) | Each location must be visited within a specified interval. | Grocery or e-commerce deliveries with promised time slots. |
| Time-dependent TSP | Travel times change depending on departure time (reflects congestion). | Urban routing affected by rush-hour traffic. |
| Dynamic TSP | New stops may appear during the day; routes must be re-optimized in real time. | Same-day delivery with last-minute orders or cancellations. |
| Warehouse routing problems | Picker paths through aisles modeled as TSP tours to minimize walking distance and labor time. | Optimizing walking paths in warehouses. |
These adaptations prove that TSP is more than an abstract exercise. It’s a mirror of daily life in supply chains.
Solving the Unsolbavle – Practically
The beauty of the TSP lies in how it has inspired decades of research. While exact algorithms (such as cutting planes or dynamic programming) can solve small and medium cases, logistics needs fast, scalable approaches. That’s where heuristics and metaheuristics shine.
These approaches don’t always guarantee perfection, but they produce near-optimal results at scales where exact methods become impractical.
2-opt and 3-opt
Local improvement methods that remove two or three connections in a route and reconnect them to shorten the tour. Fast and effective at eliminating unnecessary detours.
Lin–Kernighan heuristic
A flexible extension of k-opt moves. It adapts the number of swaps dynamically, escaping local optima and producing solutions within fractions of a percent of the true optimum—even for thousands of stops.
Christofides algorithm
A classic approximation method. For road networks that obey the triangle inequality, it guarantees a tour no more than 50% longer than the optimal. An important benchmark for solution quality.
Genetic algorithms (GA)
Inspired by natural evolution, they “breed” better routes over many generations, making them well-suited to large and messy problems.
Simulated annealing (SA)
Mimics the cooling of metals, occasionally accepting worse solutions to escape local optima. Simple to implement and good for quick improvements.
Ant colony optimization (ACO)
Models how ants lay and follow pheromone trails to find efficient paths. Particularly effective for large graph-like problems such as city networks.
In modern route optimization, these methods are often combined: a metaheuristic explores the broader solution space, while local heuristics like 2-opt or Lin–Kernighan fine-tune the details. The result is fast, scalable, and reliable routing—close enough to optimal to deliver real value in logistics operations, where perfection isn’t the goal. What matters is fast, reliable improvement.

A Practical Path Forward
The TSP demonstrates that sequencing matters. The challenge for businesses is applying that insight at scale and under constraints.
This is where modern platforms bridge the gap between theory and practice. Today, you don’t need to implement heuristics yourself: these are embedded in accessible tools.
Last Mile, from Log-hub’s Supply Chain Apps offer practical solutions that let teams model and optimize routes directly in Excel or the cloud. It calculates the shortest delivery routes by using customer addresses, stop groupings, and constraints, while outputs like route details and maps provide efficiency insights.
Why Should Logistics Leaders Care
Cost Savings
A 5–10% reduction in kilometers driven can mean millions saved annually in fuel and maintenance.
Service Quallity
Smarter sequencing reduces delays, raises on-time delivery rates, and supports tighter customer commitments.
Sustainability
Transport is responsible for roughly a quarter of the EU’s CO₂ emissions. Every kilometer avoided is less carbon emitted.
Resilience
Efficient use of fleets creates buffer capacity. The same trucks and drivers can handle more demand without scaling up assets.
Closing Thoughts
The Travelling Salesman Problem reminds us that the most complex supply chain challenges often begin with a very human question: what’s the smartest way to get from A to B, and back again?
For logistics leaders, answering that question is no longer about puzzles—it is about staying competitive, compliant, and sustainable. Efficient routing, built on decades of TSP research, is now a strategic lever: cutting costs, delivering better service, and ensuring supply chains remain viable in a carbon-constrained world.
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Since you’ve come this far, this might interest you!
Meet Supply Chain Analytics Pulse — a free platform to keep you in the loop. Get bi-weekly updates on supply chain trends, strategies, and hot topics, including sustainability, to stay ahead in the game.
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