Fuel Efficiency

Saving truck-loads when you have loads of trucks!

Winstone Aggregates is one of the highest diesel consumers within Fletcher Building with diesel representing more than 8%
of our costs.

The Challenge

With diesel representing such a significant proportion of company costs, finding ways to be more efficienct can both improve the bottom line and have a positive environmental impact.

To identify opportunities to improve fuel efficiency, a fleet audit was undertaken partly funded by the Energy Efficiency Conservation Authority (EECA). The audit confirmed Winstone Aggregates was already heading in the right direction, but it raised some important issues.

“Most of the fleet is working on ‘premium highways’ or roads that are undulating or steep,” says National Distribution Manager, Brett Horrobin.

“These roads have a negative impact on overall fuel efficiency and while we can’t do much about terrain or conditions, there are many things that we can control to improve our fuel efficiency.”


“The most obvious place to start was the choice of power plant – or trucks – and we spend time researching engine efficiency. At this stage, a combination of Detroit Diesel and Scania engines are the best fit for the operation. Both options meet the current minimum Euro4 (emission) standards for diesel engines.”

We have also achieved fuel efficiencies in the following ways:

Reducing idling time. By turning engines off when picking up loads, and better planning journeys to avoid traffic congestion, idling times have been reduced to just 6%.

Covering trucks when loaded and unloaded this can create energy savings of around 8%, even though Winstone Aggregates’ truck and trailer units are already manufactured to high aerodynamic standards. Although it’s not always possible, wherever we can, we cover loads.

Reducing vehicle speed by around 10 kilometres per hour (kph) has reduced fuel consumption by around 0.25 litres per kilometre, prompting Winstone Aggregates to fit all new electronic engines with 90 kph speed limiters. Not only do speed limiters reduce fuel consumption, they also reduce the likelihood of traffic incidents.

Tyre management for the North Island fleet is outsourced to an external tyre company, but an internal programme is operated alongside this, checking one truck and trailer unit per day for tyre pressure and general wear and tear. Operating tyres at optimal pressure can result in fuel savings of up to 3%.

Travel planning and management. GPS route monitoring minimises idling times and maximises backloading opportunities – reducing overall mileage. Where possible, trucks are sent on routes that eliminate travel on congested highways during peak times – a challenge in places like Auckland . Winstone Aggregates also operates a number of vehicles at night, estimating a 10% efficiency gain from transporting aggregates between 6pm and 6am.


Ambitious fuel efficiency targets can’t be achieved without the full support of Winstone Aggregates’ drivers, so our drivers are sent on a specialist fuel efficient driving practices course.

It’s important to show drivers how they’re performing so that they can be part of the solution, so our trucks performace is monitored and targets are set.

The importance of drivers seeing, and therefore having control of, their own fuel use statistics was illustrated when Winstone Aggregates spent three months changing fleet GPS tracking devices. During this period, data access was not possible so drivers could not be provided individual performance feedback. Average idling times during this period increased from 6% to 9%. Once the changeover was complete, drivers once again reverted to lower idling times.

Winstone Aggregates employs one of only nine SAFED NZ (Safe and Fuel Efficient Driving New Zealand) trainers in New Zealand. This training initiative has delivered significant value to our goal for continuous improvement in fleet energy efficiency, with some drivers showing decreases in fleet diesel usage by as much as 15%.


Winstone Aggregates was one of only three businesses selected to feature on The Energy Spot™.

The Energy Spot™ – the one-minute episodes promoting home energy efficiency on TV switched to a business focus for three weeks in February 2009. The episodes profiled real-life success stories from companies that are saving money through smarter energy use, including Winstone Aggregates, whose fleet efficiency initiative saved approximately $335,000 in the first year.

EECA Chief Executive Mike Underhill said: “Most businesses could significantly cut their overheads with better energy management. Altogether, New Zealand business spends about $13.5 billion on energy every year, and we estimate more than $2 billion of this goes on wasted energy. The companies profiled are great examples of what can be achieved with some leadership and focus — and what they’ve done isn’t rocket science, but can be easily picked up by others.”


Winstone Aggregates has set a fleet fuel target of 1.90 Km/Ltr for 2011. We are on track to achieve the target and, if results continue this way, we will better previous results by 0.1 Km/Ltr.

While an improvement of 0.1 Km/Ltr doesn’t sound much, it’s a 5% saving that will reduce Winstone Aggregates’ fuel use by 205,000 litres and result in all-round savings of $305,000 in 2011 (at $1.50 per litre fuel prices). It would also mean a significant reduction in emissions.

National Distribution Manager Brett Horrobin says it’s sometimes difficult to quantify individual components within the company’s overall savings – but he can live with that.

“The low implementation costs mean they are all contributing to the bottom line and providing a compounding effect to our overall savings. One key measure in fuel efficiency is Km/Ltr travelled, so if we can see this improving, we know the changes are having a positive impact.”


    • Start monitoring your fuel use
    • Do your homework on your engine choice
    • Limit speed
    • Cover trucks and trailers, loaded or not
    • Reduce excessive idling
    • Keep tyres at optimal pressure
  • Plan trips and optimise vehicle use
  • Get your drivers on board