Reducing emissions on the conventional fleet

Download PDF version

By Christopher Lyon
Director of Fleet Relations

Special contributions from
Mike Visser
Aeroz-America LLC

Mitigating environmental impacts is a key focus of many organizational and business operations. Over the past several decades, companies have pushed the envelope regarding sustainability and emissions reduction. Many have found success with unconventional technologies, such as alternative fuels and electrification — but implementation can be challenging. While this can present a great opportunity for organizations to reduce natural resource consumption, it may not be applicable to all aspects of the work truck industry. In the end, a key measurement of success is the ability to reduce energy consumption while still accomplishing work that needs to be done.

Although today’s innovative technologies offer a wide range of solutions for fleets, it’s important to consider both financials and functionality. Not every organization has the monetary ability to take large leaps into the latest alternative technology. But companies able to make the investment first need to look globally at their business. Sometimes, it’s not enough to just be green with alternative fuels — there has to be a tangible return on investment. Also, if vehicle functionality is affected, implementation could be considered a widespread failure.  Any technology, whether conventional or alternative, needs to be functional within operating goals. 

Productive energy
It’s important to manage productive energy. The most basic unit of work in the commercial vehicle market is horsepower. Although loosely defined as a measurement of power, it’s more specifically 33,000 foot-pounds of work per minute. On a practical scale, moving 33 pounds for 1,000 feet would expend one horsepower of work. Using horsepower productively is a primary factor in reducing fuel consumption, and harnessing the amount required (based on a large scale of company variables) is the first step. Remember, bigger isn’t always better.

It’s all about the burn
Most fleet managers are concerned about fuel costs, which can represent a large portion of an operating budget. But it’s not as simple as using less fuel — the organization still needs to get work done. The goal is to use less energy per unit of work completed. It’s essential to have a constant understanding of unit of work when measuring a project’s outcome. To be successful, you must perform the same amount of work with less energy, or more work with the same amount of energy. In the end, the unit of work completed stays constant, and energy consumed decreases. But before you can truly determine a strategy, it’s important to know how your trucks burn fuel.

Idling, by definition, is running an engine while stationary. It’s not possible to eliminate idling entirely, but there are opportunities and strategies to control it. For instance, think in terms of levels of complexity. The least complex solution often yields the lowest results, but is easiest to implement. As an example, while a simple, written idling policy requires few resources to produce, it makes it harder to achieve manageable and trackable results. Passive monitoring, where conventional trucks record idle time, can drive change, but requires hands-on management as well as constant monitoring and communication. More complex options include active monitoring and telematics, which provide driver scorecards and real-time feedback. Active idle mitigation technology is another alternative, where vehicles physically shut down during a pre-determined set of parameters. As complexity increases, so will implementation efforts and measurable results.

Understanding drive cycle
Drive cycle defines how vehicles are used, and can help identify strategies to reduce the burn. Let’s consider scenarios based on different driving environments. With highway operations, air in front of the vehicle is a key obstacle. A truck rolling down the highway needs to displace the air in front of it — and displacing any object requires horsepower. The amount needed to overcome air resistance is simple math — vehicle frontal area, coefficient of drag and speed. Regardless of fuel source, it’s a force that needs to be overcome — and aerodynamics can play a critical role. Other potential options for reducing coefficient of drag include adjusting placement of exterior exhaust components, adding air dams to reduce under-chassis airflow, and optimizing size and shape of exterior components. As a good rule of thumb, if it catches the wind, it contributes to coefficient of drag.

Studies are continuously conducted on effects of aerodynamic drag on commercial trucks, with analyses focused almost exclusively on Class 8 heavy-duty tractor-trailers. However, we can utilize key aspects learned from the Class 8 sector and adapt them to vocational classes. From an industry and supplier viewpoint, many users who adopted aerodynamics consistently reported measurable fuel consumption savings — all directly attributable to reduced aerodynamic drag. It can be beneficial to look at drive and duty cycle to determine if aerodynamics can help green your conventional truck fleet.

As fuel is generally the second-largest operating cost of an internal combustion engine truck — after labor — fleets are typically highly motivated to increase efficiency. Additionally, tailpipe greenhouse gas emissions are reduced at a directly proportional rate to fuel savings, providing dual benefits of lower total cost of ownership and improved sustainability. From a cost perspective, aerodynamic benefits can be obvious when reviewing return on investment. The total cost of installing fuel-saving aerodynamic products could be fully recouped in a short period of time, depending on distance traveled and local fuel prices.

Putting this into perspective, depending on operating parameters and environments, some alternative fuel and advanced technology options require a longer time period for full return on investment, and others only break even with fuel savings during vehicle life. Aerodynamics can be an effective cost reduction option for fleet managers. Many medium-duty box trucks and other vocational vehicles have the potential to realize significant financial benefits from installation of aerodynamics.

Reducing the burn
An obvious, but sometimes overlooked, strategy for reducing fuel consumption is total miles driven. While this may not be directly under a fleet manager’s control, route optimization and diesel reduction can play key roles. Unnecessary energy expended creates inefficiency that could have been used to perform work.

Vehicle weight is another aspect to consider. The more an object weighs, the more energy is required to move it. This is where understanding operations is necessary, and defining performance required should be a starting point. When building vehicles, take a look at factors such as maximum speed, driving range and cargo weight. Remember, as speed increases, so does the horsepower required to overcome aero resistance. Limiting speed can be an option, as illustrated in the chart below.

Rightsizing fuel tanks can also help reduce weight and cost (diesel weighs approximately 7 pounds per gallon). In addition, larger engines (which are heavier and require more horsepower) and greater cargo capacity (meaning more sizable loads) contribute to vehicle weight.

Driver buy-in is a primary factor in successfully influencing behavior. Once operators become aware they’re in a position to save an organization money, it’s important to emphasize benefits to the fleet and driver. Operators use these vehicles regularly and are positioned to make changes, which can range from maintaining proper tire inflation (reducing rolling resistance and premature wear), to properly loading vehicles, and avoiding unnecessary cargo and tools that creep in. All of these small adjustments can reduce the bottom line.

Understanding what’s required and rightsizing appropriately can keep overall truck weight lower, which necessitates less energy. Providing an effectively sized vehicle will allow the most efficient use of energy to get the work done. 

Bringing it all together
One single change may not result in huge savings for work trucks, but incorporating multiple strategies can have compounding effects. While alternative energy and technologies continue to play an important role in reducing environmental impacts, conventional approaches can contribute as well. Combining small changes in truck design, driver behavior and idle reduction can add up to quantifiable results. While it may not be suitable to radically change platforms, there may be opportunities, whether that includes alternative platforms, or vehicle or subsystem electrification.

Learn more
NTEA offers access to publications and reference materials on current regulations, safety standards, and other technical issues at To learn more about the tools, resources and solutions available to members, visit