What is idling?

Vehicle idling carries a heavy environmental burden. Recent studies reveal that as much as 6 billion gallons of fuel are wasted annually in the United States due to unnecessary idling, translating to millions of tons of carbon dioxide released into the atmosphere. The Environmental Protection Agency (EPA) and Department of Energy also found that personal vehicles alone contribute roughly 30 million tons of CO2 each year from idling, with commercial trucks adding significantly to this figure. When you don’t turn off your engines and leave your vehicles idling, it can lead to increased fuel consumption, carbon emissions, and operational costs.

In this guide, read on to learn about the costs of vehicle idling on fleets, key anti-idling regulations, and how innovative technologies like Samsara can help to minimize idle time.

What is vehicle idling?

Vehicle idling is when a vehicle’s engine is left running when it’s not in motion. In the fleet industry, stationary commercial motor vehicles and heavy-duty construction equipment are commonly found idling.

Idling isn’t always intentional; many people idle every day while stuck in heavy traffic or waiting in line at the drive-thru. Truckers often leave their engines idling to generate electricity  to maintain cab temperatures while they sleep. School buses idle while they wait for children to board fully. Whether intentional or not, idling consumes the same amount of fuel and generates the same amount of pollutants.

How long can vehicles idle?

Many drivers want to know how long they can leave their vehicle idling when parked. How long your vehicle can idle depends on several factors, such as:

• Overall vehicle condition: Vehicles stop idling when something breaks in the system. Leaving a vehicle idling for long periods causes stress on the vehicle and adds wear and tear. Thermostats, fan belts, and hoses are particularly vulnerable if the vehicle is not regularly maintained. Also, if some parts are defective or on the verge of failing, the vehicle won’t be idling long.

• Amount of gas: Like personal vehicles, if the commercial vehicle runs out of gas, it will stop idling and shut down. 

• Battery charge: Idling a vehicle causes its battery to drain. Drivers will need to recharge or replace it before they can start the car engine.

What are the downsides of idling?

Some idling, like vehicle warm ups, are normal, but extensive idling can have negative impacts on the environment and public health, such as:

1. Fuel consumption 

Most businesses look for ways to cut costs, not create them. In particular, businesses with large fleets are always looking to reduce the cost of fueling their vehicles. However, when truck drivers leave their motor vehicle idling on the road during heavy traffic or when parked for long periods, it causes significant fuel consumption. Approximately six billion gallons of diesel fuel and gasoline combined are wasted—without even moving.  

Vehicle idling directly impacts an organization’s bottom line. It’s estimated that idling for one hour can consume up to a gallon of fuel. A gallon may not seem like much, but incremental consumption over time—with no beneficial trade-off—adds up. As the price of fuel continues to climb, excessive idling wastes gas and can drain profits.

2. Increased maintenance

Idling for long periods isn’t good for a vehicle’s engine. Many drivers believe that leaving the engine running for a few minutes saves fuel and reduces engine wear instead of restarting. However, the reverse is true—idling damages the car engine, increases maintenance costs, and leads to downtime.

When your vehicle is idling, it’s not operating at its proper temperature. The fuel doesn’t fully combust and leaves behind a residue. This residue causes damage to fan belts, the thermostat, and the exhaust system, which costs businesses more to repair or replace parts. 

3. Pollution

When drivers leave their car idling for long periods, it releases fossil fuel emissions into the air, contributing to pollution and climate change. Argonne National Laboratory estimates that idling results in the emission of about 11 million tons of carbon dioxide, 55,000 tons of nitrogen oxides, and 400 tons of particulate matter annually in the U.S. Because of diminished air quality, vehicle idling is prohibited in many countries due to its harmful environmental effects.

4. Driver health 

With idling directly contributing to air pollution, drivers are adversely affected by proximity. Gasoline is made up of carcinogenic components and chemicals. Breathing the air surrounding an idling vehicle can lead to heart disease, damaged lungs, asthma, or other respiratory issues. 

6. Exposes fleets to theft 

Leaving a vehicle unattended and idling exposes it to theft. Would-be thieves can get into the vehicle and drive off. Thanks to today's fleet management solutions with GPS tracking, the chances of vehicle recovery are better than ever. However, the theft still causes inconvenience and leads to unexpected, costly downtime.

What do government fleets need to know about idling?

Government fleets have unique requirements for environmental and sustainability management  when it comes to reduction or mandates for greenhouse gas emissions. Electrification transition goals for EV and plug-in hybrid vehicles, and optimizing vehicle inventory is directly tied to public funds and taxpayer dollars. 

Today, public sector agencies are using smart tools to monitor fuel management, idling, fuel costs, power take-off (PTO) monitoring, electrification, electric vehicle transitioning and monitoring, and more. Idling is common with public fleets and can be complex to monitor, especially for public works vehicles when PTO is engaged. By leveraging advanced telematics tools, public fleets are enabled to analyze idling and PTO to identify waste for optimization.  

Are there any anti-idling laws in the U.S.?

Yes, there are anti-idling laws in the U.S., but they vary significantly from state to state, and sometimes even within cities and counties. As many as thirty-one states and Washington, D.C. limit idling time in some or all vehicles. 

Some states have more stringent regulations than others. State thresholds, tolerances, and fine amounts vary, with many local municipalities enacting their own anti-idling legislation. This lack of concurrence and disparity requires traveling truckers to be aware of local laws, causing confusion and complaints.

Several federal agencies focus on anti-idling research, economic incentives, and education. The U.S. Department of Energy sponsors programs that research anti-idling technologies as part of a broader goal to bring idle reducing technologies to vehicle assembly lines. Similarly, the Environmental Protection Agency has also implemented programs to promote idle reduction, such as the SmartWay Transport Partnership and the Clean School Bus Campaign.

What are idle reduction technologies?

Idle reduction technologies (IRTs) reduce vehicle idling by using an alternative technology installed on a vehicle. These technologies are energy sources that provide functions like air conditioning, or electricity, allowing drivers to shut down their engines during extreme weather.

The EPA has verified five types of IRTs to reduce emissions on heavy-duty trucks.

• Auxiliary power units and generator sets (APU/GS): An APU/GS device contains an EPA emission-certified car engine that supplies cooling, heating, and electrical power.

• Fuel-operated heaters (FOH): FOHs are small heaters that burn fuel from the main engine fuel supply or a separate fuel reserve.

• Battery air conditioning systems (BAC): A BAC system uses batteries to power an independent electric cooling system. Sometimes, these systems integrate a FOH to supply heating.  

• Thermal storage systems (TSS):  A TSS collects heat energy as a truck is driven and uses it to provide air conditioning.  

• Electrified parking spaces (EPS) / Truck stop electrification (TSE): EPS/TSE technologies provide long-haul trucks the ability to heat, cool, and power additional auxiliary devices at truck stops without needing to idle their engines.

How Samsara helps fleets reduce idling

Today, modern organizations are leveraging innovative fleet management technology like Samsara to reduce idling, minimize emissions, and achieve sustainability goals. Samsara leverages AI technology to provide real-time alerts and insights into driver behavior, which can reduce idling by proactively coaching drivers on best practices to minimize fuel consumption and improve regulatory compliance.

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Estes, the largest private freight carrier in North America, leveraged Samsara to minimize idling and reduce fuel costs. Prior to Samsara, tracking and addressing idle events was a manual, time-consuming process that often led to inefficiencies and missed opportunities for cost savings. By adopting Samsara Vehicle Telematics, Estes is able to monitor idle time in real-time, identify patterns, and take corrective action from the very first day of implementation. This capability allows Estes to coach their drivers more effectively, reducing unnecessary idling and, consequently, saving significant fuel costs—over $3 million in total. 

"We've always targeted idle time because that costs a lot of money and wastes a lot of fuel,” said Curtis Carr, Vice President of Safety and Risk Management. “With Samsara, we can identify where it has happened, how long it has happened, and then address it individually with the drivers."

To learn more about how Samsara can help you reduce idling, explore Samsara’s Platform solution and speak to our team today.