Improved driver skills can account for an increase of up to 30% in fuel economy. Companies can invest in driver training and incentives to encourage drivers to anticipate traffic, minimise idling, plan routes and other eco-driving practices, such as smoother braking and acceleration. Computer-based programs and simulators are available to assist in such training. Simple awareness-raising material such as newsletters and leaflets are also effective.
Road freight operators tend to keep aggregate fuel records across the entire fleet rather than focusing on smaller groups or individual vehicles. High-level aggregated data does not allow operators to determine which vehicles and drivers are performing well and which are performing poorly.
Data analyses of individual vehicles, drivers and routes provide the basis for improving fuel-efficiency. Many of the emerging engine and drivetrain opportunities are largely dependent on the duty cycle of the vehicles, which varies across the fleet.
Energy-usage data should therefore be captured, at a minimum, for different segments of the fleet. Ideally, it should be on a vehicle-by-vehicle basis. Monitoring of data from fuel cards, vehicle management systems, GPS and telematics can be progressively improved to enable this to be done cost effectively.
Importantly, fuel consumption and productivity should be analysed in the context of load weight using a metric such as “per tonne-kilometre”. Most trucks are not equipped to accurately measure load weight, but can be retrofitted at reasonable cost.
Route planning can reduce distance travelled, improve fleet utilisation and avoid traffic congestion.
Look for opportunities to deliver different kinds of products to multiple customers by combining the load into a single vehicle and trip. Consulting with drivers and clients can highlight where to adjust delivery schedules around peak traffic periods.
Opportunities may also exist to consolidate loads from multiple smaller vehicles into larger vehicles or to load in such a way as to maximise carrying capacity, including the use of double-stacked trailers. Longer combination vehicles (LCVs) with multiple or longer trailers are up to 20% more fuel efficient on a t/km basis than typical combination trucks. Operations are limited as LCVs are only permitted on certain routes.
Computer-based vehicle booking can help reduce fleet size and minimise total distance driven. Review of GPS data on completed tasks may also reveal inefficient routing, as well as the most efficient vehicles to use and where to reduce trips and distance driven. Some GPS devices can also receive real-time data on traffic congestion and crash sites.
Numerous websites and mobile phone applications exist to facilitate easy back loading of freight, so that less fuel is wasted on unloaded return trips.
Opportunities may exist to work with major clients to reduce and optimise the overall level of packaging used. This allows for more efficient loading of vehicles, improving productivity in terms of fuel or emissions per unit of payload.
In some cases, improvements are easily captured with a small amount of cooperation between transport operator and freight customer. In other cases, close collaboration is required along the supply chain, and trials may be needed to ensure service quality is maintained.
The principles of fit-for-purpose procurement can be applied whenever vehicles are due for replacement, refurbishment or upgrade. Poorly specified trucks waste fuel and cost more to maintain. Whole-of-life costs and maintenance costs are also reduced when engines and drivetrains are not overworked. The principles apply equally to truck bodies and trailers as they do to the base vehicle.
New truck designs are enabling fuel-efficiency improvements of up to 50%. These gains are made possible through significant improvements in aerodynamic design, hybrid engine innovations and advances in light-weighting material.
Reviewing a company’s policy on vehicle replacement schedules is worthwhile. A longer retention time can justify an investment in vehicles that are more efficient, providing maintenance programs are adequate. Conversely, if analysis indicates some vehicles are much less efficient than those currently available on the market, accelerated replacement may be justified.
Maintenance programs can reduce fuel consumption rates by ensuring vehicles are tuned for optimal performance. The potential for fuel savings and emissions abatement may be as high as 5%.
The use of low-viscosity lubricants in maintenance programs can reduce friction and energy losses. The combined effect of low-viscosity synthetic engine oils and drivetrain lubricants can improve fuel economy by at least 3%, saving nearly 2200L of fuel per year for a typical combination truck.
There are regular formal maintenance checks that drivers should carry out, such as monitoring tyre pressures. Truck tyres inflated 10psi below recommended air pressure levels can lower truck fuel efficiency by up to 4% by increasing rolling resistance.
Under-inflated tyres are more prone to irregular tread wear and reduced casing durability. Regular monitoring by drivers can generate ongoing savings. Automated monitoring and tyre-inflation systems are also available.
Modern diesel electronic engine management can often be tuned or remapped for improved performance under specific load conditions.
Reducing speed can yield significant fuel savings. Aerodynamic drag increases exponentially and becomes the major contributor to power requirements at speeds faster than 80km/h. Reducing highway speed from 100 to 90km/h can reduce fuel use by nearly 10%, and can lower tyre wear, driver stress and crash risk.
In developing a recommended highway speed, companies need to take into account the costs and logistics of labour, rest breaks and delivery schedules all of which are affected by reduced speeds.
Better fuel efficiency can be achieved by improving aerodynamics and tyre performance, and light-weighting to reduce rolling resistance. Parts and systems can be replaced or modified on existing trucks to yield a fuel efficiency benefit in these areas.
Some vehicle accessories such as lighting, air-conditioning and power-steering can be optimised for efficiency, or alternatively powered.
For example, light emitting diodes (LEDs) use up to 90% less electricity than standard lamps, saving electricity that would otherwise need to be generated by the engine-driven alternator. Companies can consider replacing incandescent globes in new trucks with high output, low power, high-intensity discharge (HID) exterior and LED interior lights.
Better designed vehicle air conditioners can reduce fuel consumption significantly while providing an equivalent level of cooling. More efficient alternators and power-steering pumps can also improve fuel economy.
Replacing accessories with more energy-efficient models can be expensive, so estimate the current fuel usage associated with the equipment to quantify the costs for upgrading these systems to determine the investment case.
Optimising gear settings results in a more efficient use of the engine’s torque more of the time, by maintaining ideal engine speeds for the conditions.
Automated manual transmission (AMT) systems can also reduce fuel consumption and GHG emissions by automating a conventional manual transmission to optimise gear shifting. An AMT takes a three-pedal manual gearbox and converts it to a two-pedal version by taking automatic control of the clutch function. The duty cycle of the vehicle should be considered, to ensure the benefits suit the application. AMTs are more suited to stop-start, high gear-shifting drive cycles.
In the heavy-duty segment, the main manufacturers all offer AMT systems. New versions of these gearboxes are bringing advanced features and integrated functionality with other onboard electronic systems. Renault also offers automated gearboxes in light commercial vehicles.
Every 10% decrease in truck weight can reduce fuel use by 5% to 10%.
Trucks that incorporate lighter materials into their design can be 4% lighter than the loaded weight of an average truck. This can save 900L per year.
Other ways to reduce vehicle weight include:
- lightweight trailers
- alloy wheels and super-single tyres
- examining fuel quantity carried
- light stillage pallets
Innovations in complex rubber compounds, casing construction and tread design, have led to the development of modern low rolling-resistance tyres that can increase truck fuel economy.
Fuel savings of 5% or more can be achieved for heavy vehicles. Fitted with low rolling-resistance tyres, a combination long-haul truck can save over 2200L of fuel per year.
Traditional dual tyres can often be replaced with single wide tyres. This can be applied to all tractor and trailer tyre positions except the steering tyres. Fuel savings of around 10% are achieved by lowering the weight and rolling resistance of the tyres and wheels, thereby reducing load on the engine.
When evaluating these technologies prior to adoption, issues such as maintenance cycles and life span should be considered.
At high speeds, aerodynamic drag can be the biggest energy drain on a heavy vehicle.
Trailer modifications, including smooth-side van trailers or side skirtings can reduce aerodynamic drag. Contrast this to drop decks with irregular shaped loads, stock crates and car carriers which can induce 10% to 30% more aerodynamic drag.
A range of truck modifications are also worth exploring including roof deflectors, chassis fairings, under-hood air-cleaners and truck vision systems that replace mirrors.
The expense of installing aerodynamic features can be quickly recovered through fuel savings. For instance, an aerodynamic long-haul truck can achieve fuel savings of over 7200L per year.
Energy loss from engines can account for up to 70% of fuel consumed, in the form of waste heat that passes through the exhaust and the cooling systems. Alternative drivetrain engine technologies can reduce these losses and significantly improve overall energy efficiency.
Fully electric powered small to light trucking vehicles with aerodynamic body design are commercially available. Large-haul electric trucks are under development.
Overall energy running costs can be 80% less than for diesel and petrol vehicles.
Hybrid electric drivetrains
Hybrid electric vehicles can deliver a significant fuel saving when matched carefully to the right application. They are well suited to urban freight operations with frequent stop-starts, which maximise the benefit of regenerative braking.
Mechanical hybrid-electric drivetrains
In a mechanical hybrid system, hydraulic accumulators (rather than the batteries typical of electrical hybrids) are used to store energy. Like hybrid electrics, the most obvious applications involve frequent stop-start driving.
Fuel and emissions reduction from implemented mechanical hybrid systems in light commercial vehicles saves 35% to 50% in fuel.
Capital costs have been cited as being approximately 15% higher than for a conventional vehicle with a payback period of 3 to 4 years. Maintenance and service requirements also need to be considered when evaluating whole-of-life costs.