How Loop helped a leading retailer avoid a 43% surge in travel distance by optimising delivery windows
CASE STUDY AT A GLANCE:
THE CHALLENGE:
A leading retailer wanted to offer customers more flexibility in choosing delivery times, but discovered that rigid full-choice models (like two-hour windows) drastically increased travel distance, fleet requirements, and idle time, undermining operational efficiency.
LOOP'S SOLUTION:
Loop simulated and modelled the operational impact of several slot strategies, comparing rigid two-hour customer-selected windows against broader morning and afternoon windows and a dynamic routing baseline.
CUSTOMER OUTCOME:
The retailer identified broad morning and afternoon windows as the operational sweet spot. This approach preserved customer flexibility while keeping distance and vehicle increases manageable, successfully avoiding a 43% surge in travel distance and turning costly rigid slots into a premium paid option.
Customer and project overview
Offering customer-chosen delivery times is a proven way to improve first-time delivery success and boost customer satisfaction. However, fixed time windows create tight constraints for vehicle routing, introducing significant complexity and cost.
A leading retailer wanted to provide customers with greater delivery flexibility but needed to ensure this enhanced service wouldn't undermine their operational efficiency.
The business needed to understand exactly how different delivery slot models would impact fleet size, route density, driver performance, and delivery performance by stress-testing rigid windows against broader morning and afternoon slots.
The challenge
Balancing efficient delivery operations with customer delight
CHALLENGE 1
Rigid customer choice
Narrow delivery windows severely reduce route density and force longer drives between stops, limiting the fleet's ability to optimise routes based on geography and logical timing.
CHALLENGE 2
Higher cost to serve
Every constraint added to a delivery window directly increases kilometers travelled, total vehicles required, and driver idle time. At scale, these inefficiencies rapidly compound to erode margins.
CHALLENGE 3
Uncertain promise strategy
Without a structured, data-backed comparison of slot models, implementing a new delivery promise carried major commercial and operational risk. The customer needed hard evidence to support its strategic planning.
The primary objective was to quantify the operational trade-offs of different delivery slot strategies and identify a model that balanced customer convenience with operational stability, one the business could implement with confidence and, where appropriate, monetise.
Loop's solution
Comparative modelling of delivery slot strategies
Loop simulated multiple delivery promise models to determine how each would impact routing efficiency, fleet requirements, and delivery performance. The analysis stress-tested rigid two-hour, customer-selected windows against broader morning and afternoon windows, using a dynamic routing baseline to produce a direct comparison of the true operational cost of each approach.
The data revealed a clear operational tipping point. While rigid two-hour slots drove up travel distance by 43% and fleet requirements by 29%, morning and afternoon windows delivered meaningful customer choice at a fraction of the cost—increasing distance by only 19% and vehicle requirements by just 10%.
This provided the exact evidence the customer needed to design a slot strategy that supported both the customer experience and long-term profitability.
The process involved
Defined delivery slot scenarios across three models: rigid two-hour windows, system-assigned slots, and morning/afternoon windows
Simulated routing outcomes for each model against a dynamic routing baseline
Measured fleet size, distance travelled, and driver idle time across scenarios
Compared cost and efficiency metrics to quantify the trade-off between customer choice and operational performance
Identified the preferred slot structure and assessed the potential to monetise premium slots as a revenue offset
Loop compared the operational impact of each model against the baseline to determine exactly how much additional cost and fleet complexity was introduced as customer choice increased. The modelling proved that rigid two-hour windows were unsustainable as a standard offering at scale.
In contrast, morning and afternoon windows provided a highly workable middle ground, maintaining route density and fleet utilisation without sacrificing the customer experience. This gave the client a clear, evidence-based rationale for their strategy, highlighting exactly where a premium rigid slot could be offered as an exclusive paid option rather than a standard promise.
Customer outcome
A more balanced slot strategy with lower operational waste
Broad delivery windows offered the strongest balance between customer flexibility and operational efficiency.
As a result:
Hard evidence that rigid two-hour slots (which increased distance by 43% and vehicle needs by 29%) were an unsustainable default offering.
The adoption of morning and afternoon windows, delivering comparable customer flexibility at a significantly lower operational impact (distance increased by just 19% and vehicles by 10%).
Clear visibility into the convenience-versus-cost trade-off across every model tested, removing guesswork from the planning process.
Confirmation that broad windows were the operational sweet spot, maintaining route density and fleet utilisation without sacrificing service quality.
A new commercial framework that allowed the retailer to offer rigid, highly specific slots as a premium paid option, effectively turning a cost liability into a new revenue stream.
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