Hybrids - can't hear 'em coming

[vrkelley]

Whoooosh....a hybrid just went by...I didn't hear 'em....

There's been a slight paradym shift....Hybrids are so quiet, you can't hear 'em go by. Be sure to look for cars...not just listen for 'em.

http://www.columbia.edu/~gsw2006/hybrid%20car.jpg

[Helmet Head]

Much of the noise made by cars is from the tires, not the engines, especially if they're going 25 mph or faster. Also, there is a considerable noise from air resistance.

But yeah, at slow speeds, like in parking lots, they can be virtually silent.

[Dahon.Steve]

Whoooosh....a hybrid just went by...I didn't hear 'em....

There's been a slight paradym shift....Hybrids are so quiet, you can't hear 'em go by. Be sure to look for cars...not just listen for 'em.

http://www.columbia.edu/~gsw2006/hybrid%20car.jpg

Get yourself a "Take A Look" mirror and you'll be able to see them. I won't ride a bicycle without one anymore.

[Bruce Rosar]

Be sure to look for cars...not just listen for 'em.Please be sure to look for anyone who's passing (not just motorists) before changing your path; even if the person you cut off is on another bike, the collision (or the avoidance maneuver) can still result in a fall. Falls cause the majority of Emergency Room visits for cyclists.

[Helmet Head]

Get yourself a "Take A Look" mirror and you'll be able to see them.
Oh yeah? What about at night when their lights are off??? (inside joke for those following the logging road thread)

[Bekologist]

hybrids driving at night down logging roads with their lights off can be safely avoided by riding on the well provided shoulder that was the source and the reason for the logging truck post, head. (inside joke for those following heads' sophistic follies in that logging thread)

i think listening for vehicle traffic can be valuable. it is not infalliable, and always look before a lateral. i could of lateraled into a truck's trailer yesterday morning on my commute if i had assumed ther space behind the truck was clear by vehicle noise alone. strong headwinds kept the auditory cues muffled.

[noisebeam]

Agree with HH, tire noise is what one most often hears from same direction traffic, well before engine noise - unless the vehicle is accerating hard. It is very hard to not have the gas engine of a hybrid not kick in when driving above 20mph or so.

Yes, I do own a Prius, my wife drives it and interestingly when I am in our front room with the windows open I can hear her drive by preparing to turn into driveway before she hits the garage door opener. Every time - and it is the tire noise I mainly hear.

A hybrid at 45mph makes just as much noise as any smaller aerodyamic car with low rolling resistance tires. Maybe even more noise as the small engine of the Prius for example is not exactly quiet when working hard. It is impossible to drive a Prius at 45mph with the gas engine not running.

As to parking lots, yes they can be silent, but one should not by relying on noise, as it bounces off of building and other parked cars and directional clues can be misleading.

Al

[vrkelley]

Good to know Al. I'm seeing more and more of them on the way home. When mixed in with other cars, it's pretty hard to tell.

[Brian Ratliff]

I have been startled by a hybrid Highlander coming up behind me for a right turn. It wasn't a case of a right hook; I was properly positioned in the road at the time and the car was always behind me, but as it passed not 10 feet away from my back wheel, there was only a slight noise from some crunching gravel on the road as it passed. It was a bit creepy.

BTW, I drive a Prius and there are times when I am going 70 with the engine cut; just coasting or on battery power alone - as I come down a hill, for instance. It is absolutely not the case that a Prius going 25 mph (or 45 or 70 mph) always has its engine running (though that is true with a Honda hybrid).

Yes, there is road noise, but I've also been in conditions on my bike where road noise is cut out by a head wind and a standard car even sneaks up on you. Road noise is high pitched and so is easily attenuated by a head wind or other interference (which is also high pitched). Engine noise is more low pitched and cuts through much interference.

It is a vast simplification to say that most noise is from the tires. There is significant noise coming from the engine, expecially in the lower frequencies. When I am riding rural roads; the most distinct sound a car makes as it is passing is the reving of the engine as it accelerates from its slow following (following me, that is) speed. Road noise is a significant portion, but it is constant and high pitched - and largely attenuated by the wind noise.

On other thing is that the gas engine on a Prius or Highlander doesn't cut in right away from a dead stop. That means that an initial acceleration is not necessarily concurent with a loud rev of an engine. Even when the car is moving, the whole point of the battery pack and electric motor is to take load off the IC engine when under acceleration. This means that any acceleration from a Prius or hybrid Highlander (and now hybrid Camrys too) will be somewhat muted.

[Dchiefransom]

I had an electric car go by me once while walking. In an urban environment wwith background noise, it was deadly quiet on a smooth, clean asphalt street.

[noisebeam]

BTW, I drive a Prius and there are times when I am going 70 with the engine cut; just coasting or on battery power alone - as I come down a hill, for instance. It is absolutely not the case that a Prius going 25 mph (or 45 or 70 mph) always has its engine running (though that is true with a Honda hybrid). .
This is true and I almost commented on this, but it is not common. Also while the engine often does not run at sub 25mph speeds, it is not clear to me if the engine shuts down when coasting down hills, I know that the display shows no engine power being used, but a full shut off is not obvious. (often the engine keeps running to charge the battery, even if it is not applying power to the wheels). I do know on one long 5mi hill I sometime drive down at 65mph the computer shows no engine power going to wheels, but also the engine does not shut off as it shows it charging batteries.
I encounter hybrids all the time on my commute and on rural roads and never once was surprised by one - but someday I will be as I've been surprised by normal vehicles behind me, sometimes wind noise, directio or other ambient noise is enough to mask a conventional engine and tire noise.
Al

[fenester]

I think all hybrid/electric cars should be required to have an external speaker which makes the Jetsons car sound. It's relatively innocuous and will make it feel like we're finally living in the future.

[noisebeam]

I think the silence if bicycle should be far more of a concern to cyclists than the (non)silence of hybrids. That is more likely to cause an accident in my opinion.
Al

[sbhikes]

I heard that they came up with quieter road materials and quieter tires but they don't use them because it's too unsafe when motor vehicles are so quiet.

I wonder what the world would be like if motor vehicles really were as quiet as bicycles?

[LittleBigMan]

I was amazed one day at being suprised by a "stealth bus." Downhill, I didn't even hear it until it swept past me.

I wonder what the world would be like if motor vehicles really were as quiet as bicycles?

We'd actually hear the crickets instead of the constant rumble of the freeway and local traffic. Ever stop to listen to the roar of thousands of engines in the distance at night? You tend to tune it out.

[ItsJustMe]

Not a new thing. I used to (unintentionally) scare joggers in my neighborhood with my 89 Ford Probe. When it was new, you couldn't hear it at low speeds over even a little bit of wind or any other kind of ambient noise.

The other end of this is the Harley riders. I have been behind Harleys that literally hurt my ears from 100 feet off from inside a car with the windows rolled up. I thought they were just being *****holes, but I asked one once, and apparently there's a belief that "loud pipes save lives" - that being insanely loud will get them noticed.

I pointed out that even the loudest bikes weren't that loud when they were approaching, only to the side and behind, and so it probably wasn't doing any good. And if it DOES do good, then everyone should be running headers and straight pipes.

I also pointed out that any moron can make something loud, it takes skill and knowledge to make something quiet. And that if riding a motorcycle is anything like riding a bicycle, not being seen is largely a matter of how the rider is driving, not how much noise the bike makes.

I heard something a few weeks ago (maybe here) that one motorcycle with loud pipes riding through a city at night can disturb the sleep of tens of thousands of people.

I grew up about 1/2 mile from an expressway, in a very rural area otherwise. Even at 4 AM the drone from the expressway was constant. Trucks make an insane amount of noise just from their tires.

[noisebeam]

I heard that they came up with quieter road materials and quieter tires but they don't use them because it's too unsafe when motor vehicles are so quiet.

Quieter road materials do exist and are now being spread all over the freeways in metro Phoenix. Its called rubberized asphault (http://www.quietroads.com/what_is_rubberized_asphalt.asp). And it is quite a bit quieter, from both interior of the vehicle and outside.
Quieter tires do exist too. They are often the low rolling resistance ones found installed on vehicles designed/marketed as high fuel economy. Tire noise is a good indication that energy is being wasted (converted to heat/sound). Heavy/aggressive tread patterns are one of several causes.
Every notice how you can hear trucks with offroad (especially mud) tires comming from what seems like miles back?

Al

[bike2math]

Yeah one of my coworkers has one and three times now he has snuck up behind me cruising through the parking lot or the slow streets nearby and scared the beegezus out of my with the horn. I guess it's funny to watch a biker in clipless pedals jump. :D

[Brian Ratliff]

This is true and I almost commented on this, but it is not common. Also while the engine often does not run at sub 25mph speeds, it is not clear to me if the engine shuts down when coasting down hills, I know that the display shows no engine power being used, but a full shut off is not obvious. (often the engine keeps running to charge the battery, even if it is not applying power to the wheels). I do know on one long 5mi hill I sometime drive down at 65mph the computer shows no engine power going to wheels, but also the engine does not shut off as it shows it charging batteries.
I encounter hybrids all the time on my commute and on rural roads and never once was surprised by one - but someday I will be as I've been surprised by normal vehicles behind me, sometimes wind noise, directio or other ambient noise is enough to mask a conventional engine and tire noise.
Al

You can feel the IC engine shut off (this occurs with mine every day since I live on a large hill). Now, the engine doesn't stop turning, but there is no fuel being burned in it. At speeds under 30 mph, the engine will frequently shut down as well and the car will run on battery power alone. The algorithms Toyota uses are pretty complex and don't key off of the speed of the car, but rather the speed, power, and torque of the IC. The gearbox is a planetary gear linking two electric motors (a traction motor on the outer ring of the planetary gear set, and a smaller motor on the sun gear) and the IC (attached to the planet gear cage). This effectively makes the main traction electric motor and the IC independent and eliminates the requirements for a transmission in the traditional sense. And Toyota makes full use of this ability to completely shut down the IC during normal driving when it makes sense. The only reason why the IC is kept spinning is to limit stresses on the bearings and gears.

[Brian Ratliff]

Yeah one of my coworkers has one and three times now he has snuck up behind me cruising through the parking lot or the slow streets nearby and scared the beegezus out of my with the horn. I guess it's funny to watch a biker in clipless pedals jump. :D

Duhh. That's because the bike jumps too. How often do you get to see that? ;)

[2manybikes]

Whoooosh....a hybrid just went by...I didn't hear 'em....

There's been a slight paradym shift....Hybrids are so quiet, you can't hear 'em go by. Be sure to look for cars...not just listen for 'em.

http://www.columbia.edu/~gsw2006/hybrid%20car.jpg


That's a very good point. Aslo when they are stopped it looks as if they are parked but they can take off instantly. Don't mistake one stopped for a parked car with the engine off.

[Da Tinker]

Ever had a Honda Gold Wing slip up on you? Those beasties run tires designed to be quiet. Some make less noise than a bike.

[I-Like-To-Bike]

Road noise is high pitched and so is easily attenuated by a head wind or other interference (which is also high pitched). Engine noise is more low pitched and cuts through much interference.

It is a vast simplification to say that most noise is from the tires. There is significant noise coming from the engine, expecially in the lower frequencies. When I am riding rural roads; the most distinct sound a car makes as it is passing is the reving of the engine as it accelerates from its slow following (following me, that is) speed. Road noise is a significant portion, but it is constant and high pitched - and largely attenuated by the wind noise.
I 'd take quiet cars anyday over the 60-mph rumbling wreck, no muffler, off road tire pickups that are so ungodly loud that I can't hear anything in my headphones until the POS is a half mile up the road. And I ain't kiddin' about that. Harleys are almost as bad. It's the low frequency rumbling in the Heartland that is the most annoying. I don't consider listening to vehicle noise as a safety bonus.

[noisebeam]

I don't consider listening to vehicle noise as a safety bonus.
hear, hear!

[recursive]

Good. Less noise to distract me from my ipod.

[vrkelley]

Less noise would be welcome. I work next a freeway that shakes the whole blg!

[sgtsmile]

I think the complexity of the toyota system vs the honda system is a good argument in favour of the honda. I am not sure about parts costs on the honda, but I do know that for some of the parts on the prius, replacement cost is so ridiculous that I would never consider it (1400 dollars for the front exhaust pipe, for example..... and aftermarket is not an option.) Mileage is the same for both cars.... plus, the honda cannot sneak up on you in a parking lot. Regarding tires, one of the things that bothers me about low rolling resistance tires is they tend to compromise on grip. I am not talking about "extreme handling" grip here, I am talking about being able to dodge around something or stop fast if the roads are wet kind of grip. If you live in an area with a lot of rain or slushy snow and cannot afford to run snow tires, a good rain tire is the way to go. (as an aside, NO tire I have ever heard makes as much noise on asphault as the competition gravel rally tires I had on my old subaru: they gripped gravel like a slick does dry asphalt, but sounded like 4 trucks with mud tires all at once...)

[mechBgon]

Oh yeah? What about at night when their lights are off??? (inside joke for those following the logging road thread)Then you just look for the light from your (current-generation, daytime-visible) blinkies bouncing back from their front license plates :)

[2manybikes]

Then you just look for the light from your (current-generation, daytime-visible) blinkies bouncing back from their front license plates :)


When riding next to mechBgon you can hear the cars driving off the road into the ditch.
Once in a while if you listen carefully you can hear the driver saying .......................
" My eyes ! My eyes ! I can't see". :)

[markf]

Much of the noise made by cars is from the tires, not the engines, especially if they're going 25 mph or faster. Also, there is a considerable noise from air resistance.

But yeah, at slow speeds, like in parking lots, they can be virtually silent.

The low rolling resistance of the OEM tires on a lot of hybrids probably makes the tires quieter, too. The extremely aerodynamic shape of the Prius probably reduces the noise of the car even more. So it doesn't surprise me that they're so quiet.

Not a lot of hybrid cars around here for some reason, so I'm just guessing.

mark

[vrkelley]

When riding next to mechBgon you can hear the cars driving off the road into the ditch.
Once in a while if you listen carefully you can hear the driver saying .......................
" My eyes ! My eyes ! I can't see". :)
:beer: :roflmao:

[mechBgon]

When riding next to mechBgon you can hear the cars driving off the road into the ditch.
Once in a while if you listen carefully you can hear the driver saying .......................
" My eyes ! My eyes ! I can't see". :)Hey! I resemble that remark! :p

[The Human Car]

Much of the noise made by cars is from the tires, not the engines, especially if they're going 25 mph or faster. Also, there is a considerable noise from air resistance.


For the average car I agree with you but not (always) these things. These quite cars are a major concern among the blind who rely on their hearing. My money is in a few years we will see these cars with some sort of noise maker ether voluntarily or by legislation.

[vrkelley]

The low rolling resistance of the OEM tires on a lot of hybrids probably makes the tires quieter, too. The extremely aerodynamic shape of the Prius probably reduces the noise of the car even more. So it doesn't surprise me that they're so quiet.

Not a lot of hybrid cars around here for some reason, so I'm just guessing.



They seem very popular here ... definately a trend.

It'd be great if they had some noise maker that could only be heard from say...50' away ... rather than .25 miles away....Around here, there's so much car noise, sometimes you can't even hear the birds.

[LittleBigMan]

I think all hybrid/electric cars should be required to have an external speaker which makes the Jetsons car sound. It's relatively innocuous and will make it feel like we're finally living in the future.
You mean like, "Peeb-be-be-be-be-be-be-be-be...?"

:roflmao: