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Electric vehicles (EVs) and gas-powered cars look quite similar on the outside. Under the hood, however, these cars are completely different. Electric cars have three main parts: a rotor, a stator, and a commutator. The motor is electric, powered by a battery. Gas-powered cars have hundreds of moving parts working together to supply power to the internal combustion engine (ICE). Do these differences under the hood mean electric cars are quieter?
Electric cars are quieter than their gas counterparts, especially at a low speed and idle. However, electric cars do generate some noise. Most of the noise will occur in highway driving. Wind resistance and tires can emit a bit of sound with increased acceleration as speed picks up to around 19mph. EV’s are so quiet that the National Highway Traffic Safety Administration (NHTSA) is requiring minimum sound requirements for hybrids and electric vehicles by 2020.
Unless you are familiar with electric cars, it might seem crazy that they are not just quiet but almost soundless—too quiet. Keep reading as we explore the noiseless world of electric cars. We’ll also dig into the new sound requirements for EV’s.
Do Electric Cars Make Noise?
The very short answer is: No. Electric cars are designed with electric motors and are silent. When an EV is cranked, there are no internal moving engine parts like fuel injectors, spark plugs, or pistons. Electric cars have an electric motor that is battery charged. Some noise will occur at higher speeds. The noise is from wind resistance and tires, not the motor.
If you’ve never driven an electric car, it’s understandable to wonder what noises they make. But personally, after pressing the start button in a Prius and not being able to tell whether it was actually running, I’d have to say that electric cars make very little noise. Beeping noises inside the cabin are the only sign that the vehicle is powering up, and even those are a bit of a mystery when you’re new to an EV. Back-up beepers are common, though, which is a change of pace from gasoline engines that only rev.
In most electric vehicles, a minor “hum” is all you’ll hear. As you accelerate from a stop, a whirring sound is typical, too. Apart from that, battery-powered vehicles don’t add a lot of noise pollution to the streets. A lack of transmission or shifting noises (electric cars only have one gear) can be disconcerting as you cruise, but it means a quieter cockpit for the driver and passengers.
You’ll still hear brake noise, of course, as well as horns honking. There’s also the noise from the friction of the tires meeting the asphalt. Wind will also continue making its way around the angles of the car.
In comparison, gas-powered cars are noisy. From the time the engine turns on until it’s turned off, they can hum, grind and squeal. Even in idle, you can hear the vibrations of a gas-powered car.
Electric cars are probably too quiet
Electric cars are quiet but will need to start making some noise.
In the last decade, some EV manufacturers have added fake noises to their cars. Safety is one of the main reasons for an electric car to make itself known, especially in a parking lot or crosswalk. The sounds are simulated but are working with the car to emit as the car turns on, backs up, or drives forward.
Other EV manufacturers offer cars sounds in trim packages. These sounds can simulate engine revving or acceleration noises. Intentions here are to deliver a high-performance sports car-like experience. Perhaps as the requirements come to fruition, these sounds will check the requirements list for safety too.
Will Roads Be Quieter With Electric Cars?
Almost all noise on roads and highways comes from gas engines, tires, and wind. The condition of road surfaces has an impact on these factors, as well. Also, the faster gas-powered cars and trucks can drive on the road, the more noise they will make. And, not all cars are well maintained. There are some noisy mufflers and unhealthy engines that contribute to the noise.
Road sounds would be significantly reduced if most vehicles were electric. There is virtually no engine noise from an electric car, even at higher driving speeds. And, the aerodynamic design of EVs means less noise from wind drag.
If every vehicle on the road was electric, sound pollution would be much less intrusive. Not only would it be quieter, but we could get rid of those startling backfires and squeals that the gas-powered cars are responsible for.
Do Electric Cars Have an Exhaust Sound?
Electric cars are almost completely silent. With an electric motor, there is no need for an exhaust system. The exteriors of EVs and gas-powered cars look similar. But, if you look close enough, you will notice that the electric car doesn’t have a tailpipe. No exhaust system translates to no exhaust sound.
We’ve mentioned in this post that there is a requirement for electric cars to emit sound. EV manufacturers have taken this opportunity to get creative. It’s an opportunity to create an identity for their electric cars with their unique sounds. Sure, it might be easy to simulate the humming of an exhaust sound or an engine idling, but that’s not what EVs are about. Or sound like for that matter.
Electric cars are the future. Maybe they should sound like it.
How Much Noise Do Hybrid Cars Make?
Though fully electric cars only have battery packs and electric engines, hybrids have internal combustion, too. The internal combustion engine helps recharge the car’s battery, so the engine types cycle on and off at varying speeds and RPM levels.
While you’re driving at low speeds, your hybrid car might cycle into silent electric mode—EV mode—and cruise quietly. At higher speeds, or with a sudden application of the gas pedal, your gasoline engine will come to life. With the internal combustion engine running, a hybrid sounds a lot like a traditional gasoline-powered vehicle.
How much noise your hybrid puts out depends mainly on the way you drive, and where. Since hybrid electric cars use their battery packs for idling when stopped, your vehicle could sound silent while waiting in traffic. But if you’re driving on a steep incline or winding road, you’ll likely use more torque and more gasoline.
The longer your trip, the more likely the gas engine will kick on, too, since it needs to power up and recharge the onboard battery. Below certain speeds, though, you can probably cruise almost silently.
What Is An Electric Car Noise Emitter?
An electric noise emitter is a device capable of transmitting an artificial sound. These devices will become increasingly more important in electric cars as sound requirements from the NHTSA’s law go into effect in 2020. All EV’s will need to make some noise.
Electric cars are so quiet that you won’t hear the usual engine rumble because there isn’t anything to hear. The lack of sound from EVs presents a safety issue for pedestrians. The blind and visually impaired are at even greater risk as the expected sound clues from gas-powered cars don’t exist.
Many EVs in the U.S. already emit some noise. The Nissan Leaf, for example, emits a sound similar to a beep when it moves into reverse or forward into drive.
And, the luxurious Porsche Taycan has an optional sound package that simulates a jet-like sound at acceleration.
EVs are expected to have external speakers that will amplify the faux sounds at low speeds. Each electric car manufacturer is working on its own set of sounds. Those that already have sounds will make improvements as needed to meet the new requirements.
Sound Requirements For EVs and Hybrids
In 2011, the NHTSA’s published findings that hybrid electrical vehicles (HEVs) were more likely to be involved in a pedestrian accident compared to their gas-powered counterparts. The study found that hybrids were 35 percent more likely to be involved in a pedestrian accident. And, 57 percent more likely to be involved in an accident with bicyclists.
To combat safety issues with noiseless electric cars, the United States is following other countries’ trends and creating legislation that mandates changes. Starting in September 2020, all fully-electric and hybrid vehicles must produce sounds when cruising under 18.6 miles per hour, per the National Highway Traffic Safety Administration (NHTSA).
The precise speed was chosen because beyond 20 mph, electric cars’ motors and brakes tend to make enough noise that pedestrians can hear them. As for the new sounds, they’ll likely be quieter than what you’re used to with gasoline engines.
Engine-mimicking sounds (at lower decibel ranges) are just one of the potential fixes car manufacturers can add to their vehicles. Rumors of consumers being able to select their cars’ soundtracks are also running rampant.
Moving forward, all-electric vehicles will need to emit warning sounds. These sounds might be beeps, or they might be closer to real engine sounds. Likely, though, the sounds will be unique to each electric car. Sound will need to be emitted when an EV is in reverse or drive at speeds less than 19 mph.
How Far Does Freeway Noise Travel?
Living near freeways isn’t always ideal, mostly because of the noise levels they generate. According to the Federal Highway Administration, freeway noise produces about 70 to 80 decibels of sound at a distance of fifty feet.
For reference, a typical conversation ranks at around 60 dB(A), and that’s when two people are about three feet from each other. The fact that freeway noise is so loud at such far distances means its impact on surrounding neighborhoods and businesses is significant.
And, the more traffic a roadway experiences, the higher the noise production is. Of course, noise from automobiles isn’t regulated, so cars, trucks, SUVs, and vans don’t necessarily have to hush. Sound from bigger trucks has reduced in recent years due to legislation on decibel production, though, which has helped decrease freeway noise pollution.
Still, with a 70 to 80 dB(A) level fifty feet away, standing by the side of the freeway isn’t very comfortable for your ears. It would sound like someone running a vacuum cleaner or hairdryer right by your head. For people at home, the sound is lessened by walls and insulation. It can still affect daily life, though, such as interrupting your sleep patterns.
Will Roads Be Quieter with Electric Cars?
In theory, roads will be substantially quieter with all-electric cars taking up most lanes. But although the lack of gas-powered engine sounds may make roadways quieter, there are other factors at play.
Elements like wind, which is a significant contributor to freeway noise for commuters, still whip around your car and wreak havoc on your eardrums. All cars still use braking systems that can cause creaking, whining, and even grinding sounds. Windshield wipers, horns, and car alarms will contribute to your acoustic experience, too.
And at low speeds, such as when traffic backs up during rush hour, it won’t be entirely silent. When the new mandates go into effect, you’ll probably hear electric cars’ “fake” engine noises, too. All told, we probably can’t expect road noise to drop off entirely.
As wonderful as it would be to cut out highway noise altogether, odds are, sticking to EV mode won’t be a panacea for freeway sound pollution problems. Still, choosing to buy an electric car does help manage both noise and environmental emissions, so it’s a worthwhile consideration if you’re in the market for a new vehicle.
New Tech, New Problem
Electric cars are changing the world. There are dozens of EV options from manufacturers like Toyota, Honda, Tesla, and Porsche. Some EV’s are all-electric, others are plug-in hybrids or hybrids. A common characteristic of all EV’s is that they are quiet. Too quiet. And, while that silence is a nice thing, it presents a new wrinkle. The all too quiet engine on a city street, in a parking lot or at a crosswalk, creates pedestrian and cyclist safety issues.
Some newer cars are equipped with safety features that alert them to a pedestrian in their path, but that still wouldn’t be enough for the soundless electric car. If an EV is stopped or traveling a low speed, it’s likely the car won’t be heard at all. Pedestrians and cyclists need to be aware of an electric car’s presence. Even other drivers need to be alert.
The quiet electric cars are going to get louder. Faux noises are expected to be unique. EV manufacturers have spent time researching sound, and we expect some cool futuristic noises to be heard from electric cars. EV’s will still be quiet compared to gas-powered cars, but we will know they are there the next time we try to cross the street.