Optimize Pick Routes and Travel Paths

Every unnecessary meter in the warehouse costs time, labor, and money. In order picking, travel paths often account for 40 to 60 percent of total pick time – significantly more than the actual grabbing and scanning. Those who systematically optimize pick routes and travel paths increase throughput without additional staff, shorten cut-off times, and create buffer capacity for peak seasons.

This guide explains how to measure travel paths, strategically assign storage locations, control routes in the WMS, and avoid common mistakes – from small in-house warehouses to professional fulfillment centers.

What Is a Pick Route?

A pick route is the planned sequence of storage locations that a picker visits in optimal order for an order or pick wave. The goal is the shortest sensible distance, taking into account:

  • physical warehouse structure (aisles, levels, zones)
  • chosen pick strategy (single-order, batch, zone)
  • item placement (slotting)
  • order composition and priority

Travel paths and pick routes are closely linked: poor slotting creates long paths, even when the WMS mathematically optimizes the route. Conversely, perfect placement helps little if the route is guided arbitrarily or alphabetically instead of logically.

Process Flow: Pick Route in Fulfillment

1
Order receipt
2
Pick list / WMS
3
Route calculation (key step)
4
Order picking
5
Handover to packing
6
Shipping

Why Travel Paths Are the Biggest Lever

Time and Cost Impact

For an average e-commerce order with 3 to 5 line items, 50 to 200 meters of travel path accumulate per pick – depending on warehouse size and item distribution. With 200 orders per day and an hourly rate of 18 euros, inefficient paths alone generate thousands of euros per month in avoidable labor costs.

Throughput and Cut-off

Shorter paths mean more orders per hour. This directly affects same-day and next-day shipping: those who want to ship by 2 PM need reserve capacity in picking – and that primarily comes from optimized travel paths, not from rushing.

Error Rate and Fatigue

Long, chaotic routes increase interruptions, orientation errors, and fatigue – an indirect driver of pick errors. A clear, predictable route reduces cognitive load and improves concentration during scan-at-pick.

Time Shares in Order Picking

Travel path

45–55 % – biggest lever

Grabbing / scanning

25–30 %

Waiting / handover

10–15 %

Other

5–10 %

Fundamentals: Warehouse Layout and Slotting

ABC Analysis as a Starting Point

ABC analysis in the warehouse is the basis for sensible slotting: A items with high turnover frequency belong close to the picking zone and at ergonomic heights (gold zone between knee and shoulder). C items with rare movements can be placed farther away and higher or lower.

Slotting rules in practice:

  1. 001. Fast movers in Zone A – maximum 10 to 15 meters from the packing station
  2. 002. Place items frequently ordered together on adjacent locations (correlation slotting)
  3. 003. Heavy and bulky items at the bottom and close to shipping, not at goods receipt
  4. 004. Seasonal items temporarily re-slot – don't plan only once a year
  5. 005. Returns and B-grade stock separate, so pick routes don't lead through restricted zones

Aisle Structure and One-Way Principle

One-way aisles in rack rows prevent opposing traffic and enable predictable serpentine routes. In narrow aisles with pallet jacks this is especially critical: reversing and turning cost more time than an additional meter straight ahead.

Warehouse Zones for Short Paths

Core: packing and shipping zone

Start and end point of every route

Ring 1: A items / fast movers

Maximum 10–15 meters from packing station

Ring 2: B items

Medium turnover frequency

Outer: C items / slow movers

Rare movements, greater distance

Route Strategies in Detail

Serpentine Routing (S-Routing)

The serpentine route guides the picker aisle by aisle through the warehouse: one aisle from north to south, the next from south to north – without unnecessary backtracking. It is suitable for:

  • single-order picking in manageable warehouses
  • fixed aisle geometry without many cross connections
  • manual pick lists when dynamic routing is not available

Return-to-Start vs. Nearest-Neighbor

Two classic algorithms in the WMS context:

Strategy
Principle
Advantage
Disadvantage
Typical Use
Nearest-Neighbor
Always to the nearest open pick location
Short total distance per order
Route hard to predict for staff
WMS with live coordinates, variable orders
Return-to-Start
Fixed start/end zone, sorting by aisle
Predictable, easy to train
Not always globally shortest distance
Small warehouses, paper lists, fixed packing stations
Serpentine routing
Aisle by aisle in S-shape
No opposing traffic, clear logic
Possible detour with few line items
Rack warehouses with parallel aisles
Zone routing
Route only within the zone
Specialization, short paths per zone
Handover between zones required
zone picking, large halls

Batch and Wave Picking: Routes Across Multiple Orders

With batch picking and wave picking, one travel path is planned for many orders. The efficiency gain is enormous – but only if:

  • the route is sorted by pick locations, not by order number
  • a clear sorting logic after picking exists (cart, bins, totes)
  • the WMS consolidates duplicates (same location, multiple orders)

A batch with 20 orders and 80 line items can generate 70 percent less travel path with good route planning than 20 individual runs – with poor planning, the error rate increases.

Travel Path by Strategy (100 Orders/Day)

Strategy
Travel path
Complexity
Scalability
Single-order
High
Low
Small volumes
Batch
Lowest travel path per item
High (sorting)
Medium volumes
Zone
Medium
Medium
Best scalability with staff

Technical Support: WMS and Labeling

WMS Routing

A warehouse management system calculates the pick route from storage location coordinates, aisle topology, and order data. Key factors are:

  • Current master data: every item relocation must be updated in the system
  • Weighting: express orders can receive shorter route priority
  • Blocking logic: exclude blocked locations and quarantine from the route
  • Feedback loop: evaluate actual travel times per route and adjust slotting

Without a WMS, serpentine sorting on the pick list is possible manually – sorting Excel or shop exports by aisle number is a first step, but does not scale beyond 50 orders per day.

Visual Orientation in the Warehouse

Clear aisle signage, colored zone markings, and consistent storage location logic (e.g. aisle-rack-level-bin) reduce search time. Floor markings for one-way aisles and pick direction complement the system route with physical guidance.

Tip: Number aisles in the direction of the standard pick route – not according to building plans from 1998. What was logical for the architect is often a detour for the picker.

KPIs for Travel Paths and Pick Routes

KPI
Definition
Target Value (Direction)
Measurement Frequency
Travel path per order
Meters from start to last pick (WMS or sample)
Reduction of 15–25 % after optimization
Weekly
Pick lines per hour
Number of picked line items per hour
Increase without quality loss
Daily
Travel path time share
Travel time / total pick time
Below 50 %
Monthly (time study)
Route efficiency
Actual distance / theoretical optimal distance
Above 85 %
Quarterly
Slotting deviation
A items outside defined near zone
0 critical deviations
Monthly

Optimization Success After 3 Months

Travel path per order

142 m → 98 m (−31 %)

Lines/hour

42 → 54 (+29 %)

Pick error rate

1.8 % → 1.2 % (−33 %)

Step by Step: Optimize Pick Routes

Phase 1 – Analysis (Week 1)

  1. 001. Time study with 10 representative orders: document travel time vs. grab time
  2. 002. Heatmap of most visited storage locations from WMS logs or manual counting
  3. 003. Update ABC classification and compare with actual locations
  4. 004. Identify bottlenecks: narrow aisles, waiting zones, intersection points

Phase 2 – Slotting (Week 2–3)

  1. 001. Relocate top 20 SKUs to near zone
  2. 002. Correlation analysis: which items are ordered together in 30 % of orders?
  3. 003. Plan seasonal reshuffling (e.g. before Christmas season)
  4. 004. Review heavy items and hazardous goods positions

Phase 3 – Routing (Week 4)

  1. 001. Activate serpentine or WMS routing and conduct training
  2. 002. For batch picking: test sorting station and bin logic
  3. 003. Pilot with one aisle or zone, then roll out

Phase 4 – Control (ongoing)

  1. 001. Discuss KPIs weekly in team standup
  2. 002. Re-evaluate slotting after assortment changes
  3. 003. Peak simulation before Black Friday: test routes and staffing needs

4-Phase Optimization (Cycle)

1
Analysis – time study, heatmap, ABC comparison
2
Slotting – top SKUs, correlation, season
3
Routing – serpentine, WMS, pilot
4
Control – KPIs, review, peak test (feedback loop)

Avoid Common Mistakes

Common pitfalls:

  • Pick list sorted by order number instead of storage location
  • ABC analysis created, but locations never adjusted
  • One-way aisles signed, but staff cut corners
  • Batch picking introduced without sorting control – error rate explodes
  • New SKUs stored "where there is space" – slotting logic undermined
  • Only relying on WMS, without checking physical aisle logic
One-time optimization is not enough. With every assortment growth over 10 percent, new suppliers, or warehouse restructuring, routes become outdated. Plan quarterly mini-audits.

Checklist: Pick Routes and Travel Paths

Before optimization:

  • Travel path time share measured (goal: reliable baseline figure)
  • ABC classes current and compared with storage locations
  • Pick strategy documented and consciously chosen
  • WMS coordinates of all active locations checked
  • Aisle signage and storage location labels complete

After optimization:

  • Travel path per order reduced by at least 15 %
  • Staff trained on new route
  • KPI dashboard or weekly report established
  • Correlation slotting implemented for top 10 item pairs
  • Peak test with increased order volume conducted

Quick-win route optimization:

  • Check aisle direction
  • Sort pick list by location
  • Relocate A items
  • Mark one-way aisles
  • Batch only with sorting
  • Activate WMS route
  • Document time study
  • Schedule monthly review

Practical Example: Medium-Sized E-Commerce Warehouse

An online retailer with 2,500 SKUs and 150 orders daily initially measured an average of 138 meters travel path per order. After ABC reshuffling (80 A items to near zone), serpentine sorting on the pick list, and switching to wave picking with WMS routing, the value dropped to 94 meters – with the same error rate.

The packing area was defined as a fixed start and end point. Items that appeared together in 25 percent of orders (e.g. filter + replacement nozzle) were placed on adjacent locations. Pick lines per hour increased from 38 to 51 – without additional staff.

Before / After: Left – A items scattered, long winding pick route. Right – A items close to packing zone, short serpentine route. Packing zone as start and end point, correlation slotting for frequently co-ordered items.

Conclusion

Optimizing pick routes and travel paths is one of the fastest levers in fulfillment: lower costs, higher throughput, less stress in the team. Success depends on three pillars – proper slotting based on ABC and correlation, suitable pick strategy with clean route logic, and continuous measurement through clear KPIs. Those who optimize once and then forget lose the gains with the next assortment push.

Start with an honest time study, move top sellers to the near zone, and sort the next pick list by aisle – not by order number. Those are the first meters on the shortest path.

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Last updated: July 6, 2026