The Car and Truck Fleet and Leasing Management Magazine

Step 1 to a Greener Fleet: Measuring Emissions

December 2008, by Jason Mathers

Fleet managers have long known how to track important fleet characteristics such as safety, fuel spend, and maintenance. However, objectively monitoring environmental performance has been unnecessarily challenging, until now.

Tracking fleet environmental performance can — and should — be straightforward. Many fleet managers already have all the data needed to track their fleet’s major environmental impact: greenhouse gas (GHG) emissions.

Monitoring and managing GHG emissions provide companies with high-quality data to help better understand their corporate environmental footprint, an issue becoming increasingly important to shareholders.


Why Greenhouse Gases Matter

The build-up of GHG in the atmosphere is raising global temperatures. These gases trap heat radiated from the earth’s surface, warming the lower atmosphere and surface temperatures. Unless we act today to reduce the buildup of these emissions, we will likely face extremely serious changes to the earth’s climate.

Transportation is a major source of greenhouse emissions, accounting for nearly one-third of U.S. emissions. According to the Environmental Protection Agency (EPA), passenger vehicles account for 62 percent of transportation emissions, and heavy- and medium-duty trucks account for another 20 percent.

Vehicles emit greenhouse gases mainly during the combustion of fuel. The most prominent greenhouse gas emitted is carbon dioxide (CO2). Methane (CH4) and nitrous oxide (N2O) are emitted in smaller quantities. Vehicles also contribute to global warming through non-combustion releases of air conditioning refrigerants (HCFCs). The good news is opportunities exist to significantly reduce these emissions.


Measuring GHG Critical

By designing their fleet "greening" efforts around the systematic measurement of GHG emissions, companies open the door to innovation, efficiency, and costs savings. This outcome-based approach empowers managers to use all tools available to them to deliver cost-effective environmental benefits.

Measuring emissions is at the heart of the program the Environmental Defense Fund developed with PHH Arval that has enabled its clients to reduce emissions, on average, by 14 percent while also reducing lifecycle operating costs.

Estimating Emissions

Calculating emissions from fuel consumption is highly accurate. Organizations without accurate fuel consumption records should explore steps to build a collection of fuel type and volume data into their accounting systems. In the meantime, managers can estimate their fleet CO2 emissions by using data on mileage and expected fuel economy.

A best practice when estimating emissions is to base estimations on fleet-specific data. For example, companies missing data from a small portion of their fleets similar in use and composition to the rest of the fleet can extrapolate from existing data.

For example, the manager of a fleet of 400 Chevrolet Impalas who has fuel consumption data for all but 50 of these vehicles could assume the remaining 50 vehicles achieve the average fuel economy of the other 350 vehicles. If mileage data is available for the 50 vehicles, their fuel consumption could be estimated by dividing the known mileage by assumed fuel economy. If mileage data also is not available, the manager can assume these vehicles emit the average amount of the 350 vehicles with good data.

A second-best method to estimate emissions is through mileage. The EPA publishes mpg ratings for passenger vehicles every year. Managers with good mileage data for their fleets can estimate fuel consumption by dividing vehicle mileage by expected fuel economy. For example,

18,000 miles / 20 mpg = 900 gallons of fuel consumed

This approach, however, does not adequately capture emissions influenced by operator behavior (i.e. idling, speeding, or underinflated tires). In addition, managers must make assumptions about their percentages of city and highway driving.


Managing Emissions

Once companies have a system in place to track emissions, the real work begins. Strategies that deliver immediate emission reductions, such as right-sizing vehicles, optimizing routing, reducing cargo weight, and minimizing idling, should be at the top of the fleet "to-do" list. Some companies might also want to explore alternative-fuel or advanced vehicle technology options. These strategies, too, can fit under a GHG management framework as long as the related emissions can be tracked.

Setting a fleet emission reduction goal is a good way to provide a focus and demonstrate a long-term commitment to these efforts. When setting the goal, companies should consider the potential emission benefits of strategies available to their fleets to improve fuel economy and reduce vehicle miles traveled. Based on this information, companies should set an aggressive, but achievable reduction goal and timeline.

"Greening" efforts will remain a focus for companies for years to come. Only by tracking fleet emissions will companies be able to document progress and make objective decisions about fleet greening strategies. Every organization is encouraged to measure fleet emissions and find emission-reduction opportunities today.

Twitter Facebook Google+


Please note that comments may be moderated. 
Leave this field empty:

Fleet Incentives

Determine the actual cost of owning and running a vehicle in your fleet. Compare vehicles by class and model.


Fleet Tracking And Telematics

Todd Ewing from Verizon Connect will answer your questions and challenges

View All


Fleet Management And Leasing

Jack Firriolo from Merchants will answer your questions and challenges

View All


Fuel Management

Bernie Kanavagh from WEX will answer your questions and challenges

View All


Sponsored by

Dennis LaLiberty began his 44-year fleet career as a Wheels trainee after college, moving up in company hierarchy to the VP of international marketing post in 1992.

Read more

Alternative Fuel Locator

Use the Alternative Fuel Locator to find stations near you.

Launch Alternative Fuel Locator

Up Next

More From The World's Largest Fleet Publisher