Never heard the term "speed breaker" used before, unless in the context of experimental race cars or rockets. You need to find a more accurate way of describing what you mean.

This technology, however inefficient and impractical, exists.

Using Rube Goldberg designs, special speed bumps generate electricity each time a vehicle passes over them. I'm not sure, they may use some type of piezo generator.

Use would be very limited.

Guys, nothing is free, the energy comes from the pasing traffic.

Sleepy

This is one of the least efficient schemes that has ever been dreamed up.

Oh come on! I'm almost positive, that besides speed bumps, we can place cars on treadmills to generate power.

Or maybe drive the car to the top of a hill, once the car crests the hill and begins it's descent on the other side, it's free power! Gravity=Energy

*[ sarcasm]

This post will self destruct in 1000 years.

*_{I've started to include this, when I can remember, because some people can't tell when I'm joking.}

In my town, these speed breakers or bumps are called "wino's" and the only thing produced are loud protests.

Please check this link http://wiki.answers.com/Q/How_the_speed_breakers_are_useful_for_the_generation_of_electricity

I regret to say that this article was incompetent. It made confusing and useless distinctions between potential and kinetic energy. It did not correctly identify the units of watts and watt-hours, and even at that the numbers were ridiculously overoptimistic. They also don't seem to know the difference between a speed bump and a rumble strip.

This recurrent folly has been around since the early 1980s at least, and seems to be a pet project of people who can't do basic arithmetic.

Sorry.

how about doing collecting electrical readings for a

database management system

project

Hello,I am new to this forum but I can still give away my idea over it.Your fianl year project is a good one as if you can install 1000 street breakers in a city, and each one produces approx. max 1watt/day then you can imagine that you can actually get 1Kw/day and it will certainly utilize in public sector entertainment or something.

The principle of production of electricity using bumpers is that ,

" If the street breaker is made using compressible platform beneath it lays a piezoelectric crystal which produces electric pulses on account of load acting upon it and one should have to do signal conditioning, and then store in a cell which can be used for electricity consumption."

OMG, I had no idea he was referring to speed bumps, and I had no idea people were SERIOUS about this!

This is the second time I've been called to duty today! Busy day for the energy fruitcake crowd.

At the very best, ASS-U-Me-ing you can overcome the serious technological and economic hurdles here, this is nothing more than another form of taxation. The extra fuel it will take for all of those millions of cars driving over millions of speed bumps will MORE than make up for any energy extracted from them. So all you are really doing is adding a "parking lot tax" to everyone who drives in there.

Now mind you, I understand that the speed bumps are currently performing another useful (?) service here, so that energy is going to be expended anyway at this point, and I can see from an economic theory standpoint that this could be considered energy recovery. But that is far from energy creation.

Then who in their right mind does not believe that if this became economically viable, parking lot owners would go overboard and municipalities would start adding them to streets and highways for no other reason than to generate power and revenue?

Luckily, I can't imagine them EVER becoming a positive ROI.

Are we sure he/she's not talking about regenerative braking?

If the crystals produce an electric charge when stressed mechanically, then there is no need to put them in speed bumps/breakers. A vehicle moving over a piece of pavement causes stress within the pavement. The entire highway system could be turned into a power generating grid.

Remember that energy cannot be created or destroyed, just changed in form. What is the energy source in the above scenario? The vehicles. Without the crystals in the concrete, energy is imparted to the pavement as it is compressed by the weight of the vehicle, just like a spring. That energy is then released BACK INTO THE VEHICLE as the weight is removed. In very simple terms, the forward half of the contact area of tire is pushing down on the pavement, and the pavement is pushing up on the rear half of the contact patch. A very small portion of the energy imparted into the pavement is converted to heat within the pavement due to friction.

Now, if any energy is to be drawn from the pavement to generate electricity, then there will be less energy to push back up on the tire. Since the road is taking energy from the vehicle but not giving it back, then it will take more energy to move the vehicle along that road than to move it along a standard road. The drivers will pay for the electricity in higher fuel expenses.

In a hydraulic analogy to the electrical scenario, the speed bumps be replaced with liquid filled bladders? A vehicle rolling over the bladder would force fluid out of the bladder through a turbine that turns a small genertor. If the fluid is forced upward into a reservior, then gravity would pull the fluid back down into the bladder. It could be passed through the turbine again to convert more energy.

In the electrical scenario, the crystals would take on a charge or potential when stressed (compressed), which could then induce a current, which would draw the charge back down. But when the stress is removed, the charge would be reduced further, and current (energy would have to be allowed to flow back into the crystal to bring the charge back to its former original. If this was not true, one could apply a weight to a crystal and get a continuous energy flow out!

You will have to use the Energy Method from Mechanics of Materials to determine how much energy a single vehicle tire would impart into a piece of pavement or speed bump. Next, use that information to determine the amount of stress that would be created. Now that you know the amount of stress, then you will be able to determine how much charge to piezocrystals would take on. Then all you have to do is figure out how to get a positive net energy output from it.

Thank you, my point exactly.

I don't understand the dirision and resistance to this idea. We use speed bumps in cites to control drivers speed, these things are there and more are appearing every day. Yes they are a pain to drivers but cities use them anyway.

If a small amount of energy can be gained from them then why not use it. Use it to light up the warning sign that says "Speed bump" or something.

I don't think the plan is to lay millions of these just to generate electricity, the plan is to use the ones already installed.

Money is no object, so long as it is someone else's money. [I'll try to search this; it's not original.]

These devices may be occasionally useful in remote locations where power requirements are low and the efficiency of alternatives is even worse. Similar to PV panels for remote weather stations and call boxes, for instance.

However, unless some hobbyist has oodles of money to burn, these are typically subsidized (= coerced) "investments," with horrible payback times. The rare exception proves nothing.

The cost per watt for piezoelectric generation sucks

of course as a design project in this case, being able to quantify the ROI & come up with a workable design, being the only real goals

any where this kind of solution would be possible or desirable solar would probably be more cost effective...

the cost to install & maintain piezo generation embedded in the asphalt?

you would still require a battery/charger

"I don't think the plan is to lay millions of these just to generate electricity, the plan is to use the ones already installed."

many of the worst blunders in history started out as great solutions to other issues. it's called the Law of unintended Consequences.

Case in point here in San Francisco that almost fits to a tee:

We have several bridges to get to SF from most directions, only by coming up the peninsula can you avoid a toll, and that will cost you in extra fuel if you try anyway. But the bridges are expensive and the toll booths slow down the commute process. Enter FastTrak, a "free" RFID tag system that allows you to pre-pay money into an account that is withdrawn when you pass under a toll scanner. Wonderful idea, cut down the time wasted in booths, they even used it to encourage carpooling by saying if you have 3 people in the car, the FasTrak system charges you Zero. Wonderfully successful.

Fat forward 3 years. the City of San Francisco is now wanting to implement "congestion pricing", by which they will charge you for driving across the city on surface streets at peak commute times. How would they implement that you say? Guess how... FasTrak! thyen the Golden Gate Bridge District has to upgrade one of the approach structures leading TO the bridge. How will they pay gfor that? Guess again... FasTrak! oh, and the people who live south of the city on the peninsula, the ones who did NOT have a bridge to cross to get to the city? Guess what... FasTrak is going to be implemented on the "freeways" that we ALREADY paid for with taxes.

Why? because FasTrak has made it easy!!!

So what started off as a great idea to save time in the bridge commutes has, within 3 years, become the scourge of every driver trying to enter or leave San Francisco!

So your belief that "I don't think the plan is to lay millions of these just to generate electricity..." is, while altruistic, unfortunately a bit naive.

A vehicle weighing 1,000 kg going up a height of 10 cm on such a rumble strip produces approximately 0.98 kilowatt power. So one such speed-breaker on a busy highway, where about 100 vehicles pass every minute, about one kilo watt of electricity can be produced every single minute.

1.) First of all try to understand the difference between work and power.

2.) Next try to figure out exactly what you have to do to extract all the work (ignoring efficiency) from 1000Kg weight which is 10 cm off the ground.

3.) Notice that 100 16 ft. cars per minute doing 30 miles per hour would need to be only 10½ ft apart.

You've spent lots of time producing a nice looking web page, and no time at all trying to understand the basic engineering or doing the basic maths.

Sorry to be such a kill joy .

We could ask admin to merge with this Threadsince a speed bump generator would be a form of tollroad

there's no free lunch :D

This subject came up on another energy topic...tesla coil etc..and was as usual ridiculed...However the traffic is there...on heavily travelled portions of major road networks it would be merely a means of utilizing freely given eneregy,that is the forward momentum of a mass of substance being cars,trucks,buses,motorcycles,to the road surface on an ongoing basis with extremes at rush hours and a paucity of input after 2 am for instance...Good environmental stewardship and likely the survival of our comfortable life styles warrants further thought etc...on this seemingly outrageous notion..Nothing is free but this is mainly transforming freely given by others available for use energy...Civil/electrical engineers united could participate favorablly if the will existed..the lure of $$ will ensure this will by tried/tested/and adapted sooner than later...

"Imagination is more powerful than knowledge"..i think A.Einstein is quoted as being the source of this pithy but seemingly,in my life experience,truth.

There is no such thing as a free lunch.

If you extract energy from the vehicles then their mpg will drop.

the rolling resistance will go up??...The energy is already being distributed to the road surface...how will it increase mpg or l/km rating..??

the rolling resistance will be increased very slightly, just because it's very small doesn't mean the losses don't exist

there are several conversions involved, every conversion has substantial losses

it would be more efficient to burn the petrol in a generator.

all i am saying is the petrol is being burned already..day in and day out ..allover this sphere based on images viewed on internet etc..why not try and utilize the burned and burning petrol as a side-line opportunity perhaps privately led or government led or whatever..$$ does not equal right..but can get to the right/light

ps...in my earlier blog /thread comment in response to Randall i meant to say the lost eneregy would perhaps decrease the mpg or km/l rating but i doubt that as nothing has changed..The vehicles still move forward with1-4 points of continuous impact on the road surface with or without a buryed ribbon of pizoelectric material..beneath the surface sufficiently so that it lasts some time..

You're still missing the point, you would be reducing the efficiency of the overall system

just because the decrease in mileage is very small, doesn't mean it doesn't exist

weather or not you believe is not relevant.

No garth i think you are missing the point...The vehicles are travelling along a roadway with an imbeded strip of pizo electric material perhaps hundreds or thoushands and yes even millions of miles long not impacting the smoothness of the road (the speed breaker idea is insulting really to the concept)so the losses to mpg etc would be minimal and perhaps non-existant depending only on the vehicles specifications/driver behaviour/weather conditions...Really a simply beautiful concept and i aim to see this one through..think of the possibilities of all those little electrical impulses(dare i say quintillions at once) summed up somehow and added to the local/national grid..What stupendous greenhouse gas emmissions could be achieved by this lonely for now notion.using quartz for sustaining humanity...mw

Complete baloney. The losses to the vehicle will always be greater than the gains to the piezoelectric strips (or whatever). If you have ever taken any classes in physics and thermodynamics, you need to take them again, because you didn't learn anything the first time.

physics sure,thermodynamics some,pizoelectrics none..but have looked at whats available on the web and while small and dc vs ac to-days electrical wizards will see the possibilities by and by...its not point source loss of energy which does happen anyway on a continuous basis(resistance to forward motion a function of rolling resistance etc..trying to overcome gravity in part) but a continuous series of compressions to the embedded pizo strip (which as far as i know is non-existant at this point in time)taking advantage of the already occuring gravitational blip at every fraction of a rotation that must be compressing both the tire and the road surface in a forward and downward vector...This is simply a thought exercise to say it could be done and i hope it is done..Wasteing power is not a good idea these days..Capturing some of that waste in whatever way makes sense is...mw

"I choose to make sense not cents..."a Buckminster Fuller saying but i can't say from what literal source

why don't you post some links to these purveyors of pixie dust?

we can always use a good laugh

just because there are losses involved in a car moving down the road, doesn't lead most of us to the conclusion that adding new ones will improve the efficiency of the total system.

no amount of quotes from great inventors will change the physics....

sigh...once again your are not adding new ones...these potential sources of energy are in this thought exercise part of the pavement to begin with...mw

Just stopping by to throw some gas on the fire. Not taking sides. This only took a minute. I don't know why martin didn't do it.

http://www.markstechnologynews.com/2008/12/piezoelectric-road-will-generate.html

http://www.gizmag.com/piezoelectric-road-harvests-traffic-energy-to-generate-electricity/10568/

http://www.wpi.edu/news/20089/asphaltnews.html

http://www.greencar.com/articles/road-future-may-produce-its-own-electricity.php

http://www.guardian.co.uk/environment/2009/feb/08/alternative-energy-speed-bumps

Well kramarat i'm still trying to make a living on the side and may eventually have stumbled on similar articles..So its already being investigated on a serious basis..thats a good thing..thanks for shareing...now i'll go back to trying to satisfy the company that pays me sufficient $$ to keep me moving forwards..:):)...mw

ps:its good to be alive...a friend of mine from years past ,Julius Bezee,said this everyday when you first met him...I agree and can only add that its a great time in the history of humanity to be alive

I suppose the first one was the best. The cars will power the road, and in turn the road will power the cars, etc., etc., etc. As we all know, three et ceteras equals perpetual motion and free energy!!!

Some of these articles gave almost no numbers at all. None of them gave meaningful arithmetic or verifiable results.

I knew I was going to regret posting that.

Here's some info. I haven't had time to read it all.

Martin owes me a beer six pack.

that's what happens when you do others homework :D

ok..next time your are in red bay,ontario,canada...drop in.whats your choice.email me first a week or so in advance as i am away from my trusty ,so far,desktop computer..for a few days at a time..this is older science after all with room for proceeding..Merci...mw

Looks like a very expensive way to generate some electricity to power street lights, traffic lights, etc.

The cool part is, that at the same time, they're coming up with LEDs and other lighting technology that uses very little power....even self contained solar cells, so I don't know if the money to install street generators will end up being worth the expense.

If you keep saying such ridiculous things, you will only attract more ridicule.

I'm going to have one last go to explain this. If you had infinite resources to make roads in whatever way you want, and, you did all the calculations, you would be able to demonstrate that you could improve the efficiency of vehicles very slightly by making roads more "rigid".

But, whatever you introduce to harvest energy from the vehicles must either:
º make the road less "rigid" and hence impact the efficiency of the vehicles, or,
º not work.

Randall,

agree entirely, see my brief post!

There are too many people who see a free lunch everywhere.

Sleepy

So what...Free energy is available..harnessing it is the key..there is giga dollars to be made surely.Those that live largely for money alone may be uncomfortable in the realm of outside the box thought.These individuals are likely less interested in the possible leaningly more (biased)towards the probable of the day.The probable is based on the current state of infinitely shareable ,built up over time in discrete little steps,base of knowledge.accumulated by humanity over the life of our civilization...Pizoelectricity may be a dead end now but it may not be in the future..

Hydro-electrcity was a fairly new approach to harnessing nature at the start of the 1900's . Production of hydro-electrical projects require a good deal of $$ to build,maintain and distribute..

All i am saying is pizoelectricity offers a clean,renewable base of some sort of power potentially useful if there is a way to generate a great deal of it on an ongoing basis. This stream of thought envisions a road bed that incorporates pizo-electric sheets in its construction,not impacting the overall construction or functionality of that roadbed in any negative manner with regards to rolling resistance of that road bed but with the added bonus of acting as a source of continuously producing pizoelectricity in sufficient quantity to be useful as a commodity shareable for $$ as that is what oils the wheels of commerce so to speak. Nothing real serious in thinking about doing that is there..mw

We are talking about 0.1% compression...i am almost sure(still checking sources available from my home environment but will check with some paid to be experts on the subject by and by)that all road surfaces at the instant of contact with a 0.5-20.0 or more ton downward pressure will compress at least 0.1% or better at every touch of the aformentioned forward moving mass in motion.But i've been wrong umpteen times before and if so i apologize for all the energy expended on my and your behalfs..mw

what you are talking about is increasing the compression from 0.1% to 0.2% by adding the generators, it's really that simple

you can't reduce or keep the deflection the same, without changing to much more expensive paving materials...

what effect would this have on the construction process? how much will it shorten the lifespan of the surface? the different rates of expansion are gonna make for some unique potholes.

it is interesting research that should be done,

is the juice worth the squeeze?

don't be surprised when it doesn't ever get implemented in a significant way

harvesting a few calories from fat pedestrians in NYC to run a few crosswalk signals seems more likely :D

Try this:

OH OH!

Kinetic energy = mv²/2. Suppose that a 3000-lb vehicle is traveling at 60 mph; then its kinetic energy is 3000 x 60²/2 = 5,400,000 (in matching units). Speed bumps can be negotiated at around 5 mph. After you have braked from 60 mph to 5 mph (with the kinetic energy dissipated into heated brake pads/disks/shoes/drums, you have only 3000 x 5²/2 = 37,500 units of kinetic energy left (about 0.07% of what you started with). That's why this concept is such a dopey loser, and why you seldom see any arithmetic on it.

The last link says they can be laid flat and be unnoticeable...........BUT!, some of these articles are three years old. I would think that some data showing them working and producing would be available by now. Can't find any.

Jeez, I don't even need you guys. I can just sit here and argue with myself.

_{I'm going to creep out of this thread now.}

Tornado,

Glad to see you bring some Mechanics and Arithmetic into this.

I was hesitant as I am a Comms engineer with a lot of Eng background but reluctant to enter a Mechanical Eng background.

Thanks for starting to put some numbers in!

Sleepy

Exactly. Of course, it is possible to get the arithmetic wrong once in a while, as I sometimes do, but the real key is to get the arithmetic out there and on the table, so that it can be examined and perhaps corrected. (And, if correction is needed, to accept it gracefully. I am perhaps one of the more trenchant commentators on CR4, but every once in a while I get to savor some crow from real professionals such as nickname, JRaef, and Abdel Halim Galala. A good debate is a good debate, even if one loses momentarily. And a kick in the butt is salutary from time to time; ya just gotta recognize it!)

There is no braking involved..its a continuous river of kinetic energy occassionaly stopping for traffic :)..mw