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Is Engine Idling Bad? (+ 5 Ways to Reduce Idling) Brian Dziuk | Mar 2, 2021 2:00:00 PM

In a lot of our posts, we discuss how using a GPS vehicle tracking system can help you keep drivers on-task and prevent excessive idle time. We frequently state that excessive idle time is not just a waste of your labor time for drivers and work crews, but that it consumes fuel and puts extra wear and tear on your fleet vehicles too.

But is a little engine idling really all that bad? What do idle engines really cost you, in the long run?

Let’s find out.

What is Engine Idling and Can You Be Fined For It?

Engine idling occurs when a vehicle's engine is left running even though the vehicle is not moving. While some idling is inevitable (such as when you’re at a traffic signal or stuck in slow-moving traffic), other times idling is avoidable. 

The Environmental Defense Fund reveals that every day, millions of cars and trucks idle needlessly in the United States and across the world, wasting money and releasing pollution into the air. Because of this, stricter guidelines from the Environmental Protection Agency (EPA) and the National Highway Traffic Safety Administration (NHTSA) are being placed on the trucking industry all the time in an effort to crack down on idle times. These guidelines can result in hefty fines even for just a short period of idling, and for a large fleet, that can really add up.

What Wastes More, Engine Idling or Restarting Your Engines?

Engine idling has got to be better than having to constantly turn your engine on and off whenever you have to stop and wait for a bit, right? Wrong!

Studies have shown that idling for more than 10 seconds actually uses more fuel and emits more CO2 than turning off and restarting an engine. So, when taking short stops, it makes much more sense to turn the vehicle completely off and then back on when you are ready to continue your trip. This minimizes both fuel use and CO2 emissions!

Why is Idling Your Engine Bad? 5 Reasons to Quit Idling!

Fleet managers are constantly worried about making the most of their limited budget, and managing maintenance and fuel costs are a huge part of this. So, why is idling bad? Engine idling can negatively affect your maintenance scheduling and fuel consumption, directly impacting your budget as well as the environment. How?

1. Engine Idling Creates “Ghost Miles”

For every two minutes of idling, your vehicle could have traveled one mile, and these "ghost miles" will still accumulate on an idling engine. According to a study, "Excessive idling can create engine wear and carbon soot buildup in the engine and components." This can lead to shortened life of motor oil, spark plugs, and exhaust systems, which means you'll have to replace those materials sooner than anticipated. 

2. Engine Idling Is Bad for Your Vehicle

When you’re idling, your engine is not operating at its peak temperature so the fuel doesn’t completely combust. This can leave behind a residue that over time will damage the vehicle’s exhaust system.

In addition, putting unnecessary ghost miles on your vehicle means you'll have to conduct routine maintenance such as oil changes sooner than anticipated. This can drastically impact your maintenance budget, leaving fewer resources for other aspects of your business.

3. Engine Idling Wastes Fuel (and Money)

Preventing engine idling can help minimize the amount of fuel that is being wasted in your fleet, and therefore the amount that you are spending on gas. According to the Environmental Defense Fund (EDF):

  • An idling car uses between 1/5 to 7/10 of a gallon of fuel an hour
  • An idling diesel truck burns approximately one gallon of fuel an hour 

With average U.S. prices for diesel fuel currently approaching $3 per gallon, that's as much as $3 an hour wasted on unnecessary fuel expenses.  

Of course, idling fuel consumption per hour for vehicles not carrying loads or using accessories (such as air conditioners) can vary greatly depending on the size of their engine. For example, the U.S. Office of Energy Efficiency & Renewable Energy reports that:

“Both compact sedans with 2.0 liter engines each consume about the same amount of fuel at idle (0.16 and 0.17 gallons per hour respectively), despite differing fuel types. By comparison, the large sedan with a 4.6 liter engine consumes just over twice as much fuel at idle… The transit bus consumed the most fuel while idling at nearly 1 gallon per hour (gal/hr). The gasoline medium heavy truck category with a gross vehicle weight (GVW) of 19,700-26,000 lbs. consumed more fuel at idle than the diesel medium heavy truck category at 23,000-33,000 lbs. GVW.”

Now, imagine that the vehicles in this example are carrying loads, people, and running the air conditioner. Next, multiply these calculations in terms of how many vehicles are in your entire fleet. If each driver is in the habit of leaving their engines idling for extended periods of time, this adds up to significant money that they’re essentially leaking out their exhaust pipes.

4. Engine Idling Exposes Vehicles to Theft

You can be sure that some of your drivers keep their vehicle idling while they run into a convenience store, fast food joint, etc. This is an open invitation for thieves, and can put the vehicle at risk for theft. In fact, the National Insurance Crime Bureau (NICB) found that 81,911 vehicles — 11% of all vehicles stolen in the United States in 2018 — had the keys or fobs inside. And the number might even be higher, the bureau said.

5. Engine Idling Damages the Environment & Public Health

When you waste gas through engine idling, you aren't just throwing money down the drain—you're also expanding your carbon footprint. In fact, for every 10 minutes your engine is off instead of sitting idle, you'll prevent one pound of carbon dioxide from being released into the air. 

Since carbon dioxide is a primary contributor to global warming, minimizing engine idling, and therefore the amount of carbon dioxide your fleet is releasing into the environment, helps to create more sustainable and eco-friendly business practices. That’s not all; idling fumes have been linked to major health concerns, such as asthma, lung and cardiac disease, and even cancer.  The less your fleet puts out, the less people breathe in.

Five Ways to be Idle-Free

It’s one thing for regulatory agencies to tell the public to reduce their idling; there’s no need to let a car warm up for 15 minutes on a wintery morning! But what are long-haul truckers, who need to park for long periods of time to sleep and to comply with regulation rest breaks? They need power in their cabins to cook, watch television, and sleep at a comfortable level.

Thankfully, there are some solutions. Here are five tips to reduce idle time within your fleet, or perhaps just make your fleet idle-free!

1. Turn Off Engines After Idling 10+ Seconds

We mentioned it earlier but it bears repeating: restarting a vehicle does not burn more fuel than leaving it idling for more than 10 seconds. While it’s not likely drivers will agree to turn off their engines at lengthy traffic lights, there’s no reason to leave it running in the parking lot while they run an errand or pop into a store to get a snack.

2. Warm Up Engines By Driving, Not Idling

The best way to warm a vehicle’s engine is by easing into your drive and avoiding excessive engine revving. After just a couple of seconds, the vehicle is safe to drive and the engine will warm twice as quickly when moving. This is also the best way to get your vehicle's heating and cooling system to deliver warm or cold air quicker.

3. Install Truck Auxiliary Power Units

An Auxiliary Power Unit (APU) is a game changer for the trucking industry. These small, efficient motors are mounted on the side of a truck just behind the sleeper cab. You might be thinking, “how am I going to reduce cost by adding another motor into the equation?” 

Well, think of it this way. A truck’s main engine is big and bulky, and its primary goal is to provide enough power to pull heavy loads long distances. An APU is much smaller, and is designed for smaller tasks, such as keeping the heating and air conditioning on, or for powering a phone or laptop. They’re much friendlier when it comes to fuel consumption than the main engine.

4. Adopt Auto-Stop/Start Technology

Auto-stop/start systems have been in Europe for decades, but didn’t catch on until recently in the United States. So how do they work? To reduce idle time, this technology automatically shuts the engine off when a vehicle is at a complete stop. Then, it automatically starts back up when the driver taps the gas. 

While this technology isn’t yet widely used in fleet management, expect to see it become more popular. Automotive Trends reveals that vehicles with start-stop systems represented nearly 40% of Ford’s 2018 model year production, and almost 25% at General Motors. In fleet management, start-stop systems could ultimately save fleets a lot of fuel (Best Ride reports fuel economy savings of about 3-5% for the average person’s workday commute; for a fleet, of course, that would be significantly more). 

Read more about Auto-Stop/Start Vehicles from the North American Council for Freight Efficiency (NACFE).

5. Employ GPS Tracking

GPS tracking for fleet vehicles can help with unnecessary or excessive idling by tracking driver activities and keeping a log of hours of service (HOS) and how drivers are using their vehicles on the job. From here, it’s possible to spot bad habits such as excessive idling, giving you a chance to address the problem.

Of course, not all idling is the result of bad driving habits. Sometimes, traffic jams occur that can trap drivers in place without giving them the freedom to simply kill the engine to save fuel. It’s possible to reduce engine idle time by finding alternative routes when your driver’s original path is blocked by heavy traffic, giving you the ability to reroute drivers away from clogged highways and onto routes that will keep them moving forward.

You’ll find that, over time, the productivity improvements and reduction in idling can more than pay for the cost of a GPS tracking system (plus GPS tracking can monitor engine performance and help ensure each vehicle within your fleet is regularly maintained to avoid costly repairs).

Get Started with Rastrac Today

When you are able to improve the efficiency and productivity of your vehicle fleet through the integration of a high-quality fleet management system, you may be surprised how quickly you can see a return on your investment. This is true even when it comes to something that, at first look, may seem inconsequential, like engine idling. Over time, the benefits really add up!

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