Case Study: Temperature-Controlled Fleet Cuts Fuel Costs by 12% with Speed Limiters
Case Study: Temperature-Controlled Fleet Cuts Fuel Costs by 12% with Speed Limiters
Illustrative case study representing typical results for temperature-controlled and refrigerated fleet operators deploying AutoKontrol speed limiter technology.
Overview
| Detail | Information |
|---|---|
| Sector | Food distribution (temperature-controlled) |
| Fleet size | 85 refrigerated HGVs |
| Vehicle types | 18t and 26t rigids with integral refrigerated bodies |
| Deployment period | 6 months |
| Total annual fuel saving | £180,000 |
| Tyre cost reduction | 8% (£22,000 annually) |
| Delivery schedule adherence | Improved by 6% |
Temperature-controlled food distribution is one of the most challenging environments for fleet fuel management. Every vehicle carries two fuel-hungry systems: the traction engine and the refrigeration unit. Fuel costs represent a disproportionate share of total operating costs, and delivery windows are tight enough that there is always pressure on drivers to recover time lost to traffic or loading delays.
For one food distribution company running 85 refrigerated HGVs, those delivery pressures had quietly enabled a culture of motorway speeding that was costing the business far more than it saved in journey time. AutoKontrol’s TrackSpeed deployment changed the picture: a 12% total fuel reduction — across traction and refrigeration combined — delivered £180,000 in annual savings, while delivery schedule adherence actually improved.
The Challenge
The Cost Structure of a Refrigerated Fleet
Refrigerated HGV operators face a fuel equation that differs from standard freight. A typical 26-tonne rigid with an integral refrigerated body might consume:
- Traction engine: 28–35 litres per 100km at speed
- Refrigeration unit (TRU): 4–8 litres per hour, depending on ambient temperature and body opening frequency
TRU fuel consumption is relatively independent of vehicle speed — it is driven by thermal load and ambient conditions. However, traction engine consumption increases sharply with speed. For a refrigerated HGV running at 65 mph instead of 56 mph on motorway sections, the traction fuel penalty is 15–20% on those road sections.
For this operator, traction fuel represented approximately 72% of total fuel spend. A 15% saving on motorway traction consumption — which represented around 60% of total mileage — translated to a significant total fleet saving.
Delivery Pressure Driving Speeding
The company operated 14 distribution routes covering most of England and Wales. Route analysis showed that 8 of the 14 routes had average scheduled journey times that, in practice, left insufficient buffer for driver breaks, loading variations, and traffic. Drivers on those routes were consistently making up time on motorway sections.
Fleet management was aware of the speeding but faced a dilemma: tightening schedules further was not commercially feasible, and the existing speed limiters were set to 60 mph — above the legal 56 mph limit for this vehicle category — due to an historic miscalibration that had never been corrected.
Tyre Costs: A Secondary Concern Becoming Primary
Tyre replacement costs on the fleet had increased 22% over two years. While some of this reflected tyre price inflation, the maintenance manager believed that driving style — specifically higher motorway speeds and the associated braking patterns at delivery points — was accelerating wear. This view was supported by the pattern of tyre replacements clustering on the routes with the highest average speeds.
The Solution
TrackSpeed Deployment with Calibrated Speed Profiles
AutoKontrol assessed the fleet and recommended TrackSpeed across all 85 vehicles. The calibration approach required careful thought: simply imposing 56 mph across all vehicles on all roads without addressing the underlying schedule pressure would not work — it would generate driver resistance and could actually worsen delivery performance if drivers felt the schedule was impossible.
Working with the company’s Route Planning Manager, AutoKontrol modelled the impact of 56 mph compliance on each route’s scheduled journey time. The analysis revealed that the schedules were tighter than assumed — but the actual time lost to strict 56 mph compliance was smaller than expected, averaging 8–12 minutes on the longest routes.
Armed with this data, the company made two parallel changes:
- TrackSpeed deployment with hard speed limits correctly calibrated at 56 mph for all vehicles
- Schedule review on the 8 problematic routes, adding 10–15 minutes of buffer time through modest route and departure time adjustments
The schedule review was enabled by the route modelling data AutoKontrol provided — data that the company had not previously had access to.
Driver Communication: Reframing the Conversation
The driver briefing programme addressed the speeding culture directly but constructively. Key messages:
- The company had reviewed schedules to reflect realistic 56 mph journey times — drivers were not being set up to fail
- Fuel savings at fleet level translated to business sustainability and job security
- TrackSpeed data would be used to identify drivers who were managing efficiently, not just to flag those who were not
- The fuel saved would partly fund the schedule adjustments and driver break facilities improvements
Driver engagement was higher than anticipated. Several drivers commented that they had felt pressure to speed but had not wanted to — the speed limiter gave them a legitimate reason to comply with a limit they already knew was right.
Results
Fuel Savings Breakdown
| Category | Before (Annual) | After (Annual) | Saving |
|---|---|---|---|
| Traction fuel (all vehicles) | £1,248,000 | £1,098,000 | £150,000 |
| TRU fuel (all vehicles) | £312,000 | £282,000 | £30,000 |
| Total fuel spend | £1,560,000 | £1,380,000 | £180,000 |
The TRU saving — £30,000 — was a secondary benefit not initially anticipated. Analysis suggested two contributing factors: lower traction speeds reduced aerodynamic buffeting around the refrigerated body (reducing thermal load slightly), and driver behaviour improvements including reduced unnecessary door openings correlated with the broader behaviour change programme.
Tyre Cost Reduction
Annual tyre spend fell from £275,000 to £253,000 — a reduction of £22,000 (8%). The reduction was most marked on the routes that had previously shown the highest speeding levels.
Delivery Schedule Adherence
Measured against customer delivery windows, on-time performance improved from 91.2% to 96.7% in the 12 months post-deployment. This was counter-intuitive — the expectation had been that strict 56 mph compliance would make schedules harder to meet, not easier.
The explanation lay in two factors: the schedule adjustments had corrected the existing tightness, and fewer speeding-related incidents (three fewer accidents in the year) meant fewer significant delays affecting multiple deliveries.
ROI Summary
| Item | Annual Figure |
|---|---|
| Fuel saving | £180,000 |
| Tyre cost reduction | £22,000 |
| Insurance premium reduction | £14,500 |
| Accident cost reduction (3 fewer incidents) | £31,000 |
| Total annual benefit | £247,500 |
| Hardware + installation (85 vehicles, one-off) | £68,000 |
| Annual TrackSpeed subscription (85 vehicles) | £20,400 |
| Payback period | 4.5 months |
Key Takeaways
- For refrigerated fleets, speed limiters deliver fuel savings primarily on traction — but TRU benefits are a secondary gain worth modelling
- Schedule pressure is frequently the root cause of speeding culture — addressing it alongside the technical solution drives better outcomes
- Route modelling data from TrackSpeed can justify schedule adjustments that were previously difficult to evidence
- Driver acceptance is higher when the schedule has been reviewed in parallel — drivers need to know the expectation is achievable
- Delivery performance does not have to suffer — when schedules are realistic, compliance and on-time delivery improve together
Calculating Your Cold Chain Fleet’s Savings Potential
AutoKontrol has extensive experience with temperature-controlled fleet operators. Our TrackSpeed solution is proven across refrigerated HGV, multi-drop van, and specialist cold chain applications.
For a bespoke fuel savings analysis based on your fleet’s routes, vehicle types, and current fuel spend, our team can provide a detailed projection before you commit to deployment.
Explore more detail on fuel savings from speed limiters, understand the insurance premium benefits, or model your own return with our speed limiter ROI guide.
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