Minor Project Report
‘A Non Invasive Tyre Burst Prevention System’
AMITY SCHOOL OF ENGINEERING
Guided by: Submitted by:
Dr Ashwani Kumar Dubey Ayush Sharma
Assistant Professor, A12405113009
ECE DEPARTMENT Roll No. ECE/09
I take this opportunity to express my profound gratitude and deep regards to my Mentor Dr Ashwani Kumar Dubey for his exemplary guidance, monitoring and constant encouragement throughout the course of this thesis. The blessings, help and guidance given by him time to time shall carry me a long way in the journey of life on which I am about to embark. I also take this opportunity to express a deep sense of gratitude to the Mentor for his cordial support, valuable information and guidance, which helped me in completing this task through various stages.
Lastly, I thank almighty, my parents, and friends for their constant encouragement without which this assignment would be completed.
This is to certify that Mr. Ayush Sharma student of B.Tech. Electronics and Communication Engineering, has carried out the work presented in the project of the Minor Project report entitle ‘A Non Invasive Tyre Burst Prevention System’’ as a part of Four year programme of Bachelor of Technology in Electronics and Communication Engineering from Amity School of Engineering, Amity University, Noida, Uttar Pradesh under my supervision.
Dr Ashwani Kumar Dubey
Amity School of Engineering, AUUP
Table of Contents
Chapter Title Page No.
Abstract of work done 2
1 Introduction 3
2 Tire Pressure Monitoring Systems (Direct vs. Indirect) 7
3 Working of TPMS 9
4 Concerns related to TPMS 9
5 TPMS Block Diagram 13
6 Image Processing Result 15
7 Conclusion 18
8 References 18
This report presents a critique of work done as 40% of the vehicular accidents, which left many people dead and several others injured, have been due to tyre bursts. Out of these nearly 60% was due to incorrect tyre pressure. Incorrect tyre pressure leads to overheating of tyres and cause bursts. Due to advancement in automobile technologies, we have developed power steering that feels light even if the air pressure is less in car. In case of accidents, one gets seconds to react, which often leads to deaths.
In order to improve its overall efficiency, we can have images of front tyres processed separately and rear tyres separately, because, people often overload the boot space when travelling, and that puts pressure on rear tyres.
Chapter 1: Introduction
When something bursts or when you burst it, it suddenly splits open, and air or some other substance comes out. Same is the case in a tyre burst. Parts of vehicles tyres split open due to heat and friction. Tire failure comes from a combination of stress and heat. Low tire pressure + an injury to the tire + high speed will do the trick, mainly because low tire pressure means the tire does not keep its shape and the excessive flexing while rotating causes lots of heat and deformation. However, without knowing the exact. Usually overinflating tires by 10psi / 70 kPa is no big deal since the recommended pressure is often well below the maximum sidewall pressure, which is high and may make the ride unsmooth but will most likely cause the tires to burst.
A tire has a flat spot on the bottom, from the weight resting on it. As it rolls (picture this in your mind) the rubber that is flat then moves up and becomes round again. Consequently, the part that was round is now touching the ground and is flat. This is the normal flexing of a tire. But, the problem is that this flexing creates heat. The faster the tire is spinning on the ground, the more it is flexing, the more heat it is creating. Hot air takes up more space than cold air. When the air inside a tire gets too hot, it becomes \"bigger\" and causes the tire to explode. That is why a tire on your car is guaranteed to a certain speed.
A tire-pressure monitoring system (TPMS) is an electronic system designed to monitor the air pressure inside the pneumatic tires on various types of vehicles. TPMS report real-time tire-pressure information to the driver of the vehicle, either via a gauge, a pictogram display, or a simple low-pressure warning light. TPMS can be divided into two different types – direct (dTPMS) and indirect (iTPMS). TPMS are provided both at an OEM (factory) level as well as an aftermarket solution. The target of a TPMS is avoiding traffic accidents, poor fuel economy, and increased tire wear due to under-inflated tires through early recognition of a hazardous state of the tires.
Fig1.1: TPMS Icon
The various tire pressure monitoring systems (or TPMS) used by auto makers are designed to monitor the air pressure in a car\'s tires. The idea behind a TPMS is primarily safety-related -- underinflated tires offer a less stable ride, and they\'re more prone to possible blowouts. By calling attention to an \"underinflation event,\" the system can prompt the driver to inflate the tire (or tires) to the proper levels.
Sensors within the tire, or on the car, send information to one or several modules in the car. These modules are programmed with a range of acceptable circumstances. For direct tire pressure monitoring, this is often between 28 and 35 pounds per square inch (psi) of air in the tire.
This rather innocent light has a tragic origin. During the late 1990s, more than 100 automotive fatalities were attributed to Firestone tires that lost their tread when they were run underinflated, and friction heated them beyond their capability to handle. The tires blew out or delaminated, and this led to the rollover of the vehicles they were on. Most of those vehicles were Ford Explorers, and many times one or more of the occupants died.
The fatalities led to two major changes to the automotive industry. The first was the Transportation Recall Enhancement, Accountability and Documentation Act (The TREAD Act). The act, later signed into law, required tracking of, and response to, any possible danger signs from vehicles that would require a recall or posed a safety risk.
The second major addition was the requirement of a TPMS system on all cars built after 2007 in the United States. Like most quickly-introduced changes, there were problems with the systems. But as technology improves, and engineers refine how the systems function, they\'re becoming smoother and more reliable.
Chapter 2: Tire Burst Handling
Tyre blowout ranks the highest on any highway driver’s list of fears. With good reason too, as a tyre burst could lead to a complete loss of car control. With SUVs & MUVs, there is the possibility of a flip-over too. A blowout is dangerous no matter how good a driver you are or how safe your car is.
Fig2.1 A burst tyre
2.1 Steps to handle a Tyre Burst
• Start with maintaining a safe driving speed; there are just no two sides to this. The lower your speed, the higher your chance of survival. A blowout at 80 - 90 kph will be far less dramatic than one at 140 - 150 kph. Indeed, if you survive a tyre burst at 150 kph, consider it a gift of God.
• Do NOT slam on the brake pedal. Of course, this is easier said than done, as our brains are hardwired to instinctively jam the brake pedal in an emergency. Hard braking is actually the worst thing you can do as it will further imbalance the vehicle and throw it out of control.
• Don’t abruptly take your foot off the accelerator. Do it slowly & gradually. In fact, Michelin recommends that you maintain accelerator input momentarily, before releasing it slowly. The deceleration force from a blown tyre is so strong that your car will anyway slow down rapidly. If you have engaged cruise control, be sure to disengage it immediately.
• Try your best to keep the vehicle pointed straight. Cornering or turning with a blown tyre will greatly upset the car’s composure. If your car is pulling to one side, you might need to pull the steering in the opposite direction to keep it going straight. This is critical, else you risk drifting into the road divider or worse still, the opposite lane.
• Do NOT attempt to over-correct. The key is to maintain the vehicle’s stability. A sharp yank of the steering wheel can result in a rollover. Even when you have gained control and are slowly moving to a safe parking spot, do so with the mildest steering inputs possible.
• Allow the vehicle to gradually coast to a stop. Use engine braking if necessary. Lightly engage the brakes only when your car has decelerated to a slow speed. Use the turn indicators and pull over safely off the road. Drive on the bare metal wheel if you have to, but do NOT stop in the middle of the road as you run the risk of getting rear-ended by a speeding car. Remember to activate your hazard lights when stopped.
• If your car pulls to the left or right side and the steering has gotten heavier, either of the front tyres has burst. The direction that the car pulls in is the side of the damaged tyre. On the other hand, if your car weaves, a rear tyre has blown. Again, don’t brake. It can lead to your car fishtailing.
• Always drive with both hands on the steering wheel. It’s difficult to control the car in an emergency situation if you have only one hand on the wheel (and the other holding a coffee cup).
• Understand that your car will behave very differently with a blown tyre. Effectively, the vehicle now has only 3 contact patches with the road (instead of 4). Any sharp inputs (steering, brake, accelerator) must be avoided.
• If you drive an SUV or MUV, the probability of a rollover is extremely high. SUVs also have a greater chance of losing stability and steering control. Maintaining a conservative cruising speed is recommended.
• Rubber parts or a broken wheel could have damaged other components of your car. Have a mechanic thoroughly check your car before fitting the spare wheel and driving away. If the extent of damage is severe, call for a tow truck. Most car manufacturers & expressways offer road side assistance now.
• The situation worsens if the roads are wet. It’s best to maintain a lower driving speed in the monsoons. On the flip side, the odds of an overheating tyre are also lesser in rain or cold weather.
• Above all, try to remain as calm as possible. You shouldn\'t panic and you certainly shouldn\'t overreact. In most cases, but not always, a tyre burst is accompanied by a blast sound or a loud pop.
2.2 Reducing the odds of a Tyre blowout:
• Under-inflation is the NO.1 cause of tyre bursts. Some studies suggest that it is responsible for 75% of all blowouts. Under-inflated tyres suffer from excessive flexing and thus, overheating. Be disciplined in checking the air pressure of all tyres (including the spare) before hitting the highway. Always check the pressure when the tyres are cold (typically, less than 5 km of recent running). Invest in a high quality pressure gauge as petrol pump readings may be inaccurate.
• Check the air pressure every week or fortnight. This way, a small puncture (also known to cause blowouts) will catch your attention.
• There is nothing more critical to safe driving than healthy tyres. Visually inspect all tyres (including the spare). If you spot any bulges or cuts, that is bad news. Tyres can also get damaged by impact against kerbs, dividers and large potholes.
• Use tubeless tyres. The old tube-type tyres have a higher chance of a dangerous blowout. Good news is, tubeless tyres are OEM fitment on nearly all passenger cars sold today, and the norm in the after-market too.
• Use high quality tyres from a reputable brand. Avoid cheap, unknown imports. In addition, never buy used tyres or retread your old tyres. It must be added that runflat tyres can be lifesavers in a blowout situation.
• Check the remaining tread depth of your tyres. Not only does additional tread depth help prevent punctures, it also greatly helps grip levels. If the tread has worn out, get a new set immediately.
• If your tyres are over 5 years / 40,000 kms old (lesser for performance rubber like the Eagle F1), you should consider replacing them. The older & more wornout that your tyre is, the higher the chance of a blowout.
• Never overload the vehicle. Ensure that your tyre’s load rating (specified on the sidewall) and vehicle payload capacity are never exceeded.
• Avoid approaching the \'speed rating\' of your tyre. If you do a lot of highway travelling, ensure that your tyres have a rating well above your average highway speeds.
• Don’t get temporary / shoddy puncture repair work done. The mushroom + plug type repair is the most recommended
• If a tyre has suffered sidewall damage, get rid of it. Keep in mind that driving a considerable distance on a puncture can damage the sidewall.
• Stability Control Programs (e.g. ESP) are lifesavers in a tyre burst situation. Consider this when shopping for your next car.
• While tyre sealants cannot prevent tyre overheating (and eventual blowout), they can fix slow punctures and thus prevent under-inflation.
• If your car is equipped with poorly designed wheel caps, get rid of them. Some wheel caps can actually rub against the sidewall & damage it.
• Concrete roads might make the tyre run hotter.
• It is recommended to take a break after every 90 - 120 minutes of driving. This refreshment stop will not only do the driver some good, but also allow the tyres, brakes, clutch etc. to cool down. Give your car & tyres a visual check during these chai breaks.
Fig 2.2 Burst out tyre
Fig 2.3 Bulge on sidewall
Chapter 3: Tire Pressure Monitoring Systems (Direct vs. Indirect)
Have you ever seen a vehicle with one or more tires that appear noticeably low on tire pressure? Didn\'t you want to warn the driver of the situation before that slight inconvenience became a calamity? What if the vehicle with the low tire pressures is the one you\'re driving? Wouldn\'t you want to be warned?
The United States Department of Transportation (DOT) National Highway Traffic Safety Administration (NHTSA) has developed a Federal Motor Vehicle Safety Standard that requires the installation of tire pressure monitoring systems (TPMS) that warn the driver when a tire is significantly under-inflated. The standard applies to passenger cars, trucks, multi-purpose passenger vehicles and buses with a gross vehicle weight rating of 10,000 pounds or less, except those vehicles with dual wheels on an axle.
Maintaining the correct tire pressure for a vehicle is an important factor in how much load its tires can safely carry. The correct pressure will carry the weight without a problem. Too little tire pressure will eventually cause catastrophic tire failure.
Tires aren\'t invincible. They are made of individual layers of fabric and steel encased in rubber. If a tire is allowed to run low on air pressure, the rubber is forced to stretch beyond the elastic limits of the fabric and steel reinforcing cords. When this happens, the bond between the various materials can weaken. If this is allowed to continue, it will eventually break the bonds between the various materials and cause the tire to fail. And even if the tire doesn\'t fail immediately, once a tire is weakened it won\'t heal after being re-inflated to the proper pressure. So if a tire has been allowed to run nearly flat for a period of time, the tire should be replaced, not simply repaired or re-inflated.
Studies have shown that running tires with too little air pressure is not uncommon. It\'s been estimated that about one out of every four vehicles on the road is running on under-inflated tires. This also means that one out of every four drivers is needlessly sacrificing their vehicle\'s fuel economy and handling, and reducing their tires\' durability and tread life.
This has made tire pressure maintenance an important safety issue throughout the automotive industry and caused the U.S. government to pass legislation mandating tire pressure monitoring systems. The main purpose of these systems is to warn the driver if their tires are losing air pressure, leaving the tires under-inflated and dangerous.
What types of systems are being used now? How do they work? Which works the best?
The National Highway Traffic Safety Administration (NHTSA) provides vehicle manufacturers options with which they can comply with the law. One option is to install a direct tire pressure monitoring system that uses pressure sensors located in each wheel to directly measure the pressure in each tire and warns drivers when the air pressure in any of their tires drops at least 25% below the recommended cold tire inflation pressure identified on the vehicle placard. Another option is to install an indirect tire pressure monitoring system that would warn the driver when a single tire has lost at least 25% of its inflation pressure compared to other tires on the vehicle. While direct systems could offer more precise warning thresholds, indirect systems cannot offer the same information or accuracy.
Fig. 3.1: Direct vs Indirect TPMS
3.1 Direct Monitoring Systems
Direct tire pressure monitoring systems measure, identify and warn the driver of low pressure. Because direct systems have a sensor in each wheel, they generate accurate warnings and can alert the driver instantly if the pressure in any one tire falls below a predetermined level due to rapid air loss caused by a puncture. In addition, direct tire pressure monitoring systems can detect gradual air loss over time. Some direct systems use dashboard displays that provide the ability to check current tire pressures from the driver\'s seat.
Direct systems attach a pressure sensor/transmitter to the vehicle\'s wheel inside the tire\'s air chamber. Most Original Equipment and some aftermarket systems attach their air pressure sensor/transmitter to special tire valves. While the presence of a metal clamp-in valve typically identifies the presence of a direct tire pressure monitoring system, special snap-in rubber valves have also been used to support direct system sensors. The transmitter\'s signal is broadcast to the in-car receiver and the information is displayed to the driver.
Some aftermarket and Original Equipment direct monitoring systems attach the sensor/transmitter to the wheel with an adjustable metal strap. These sensors/transmitters and their straps only weigh a few ounces and allow virtually universal application on car and light truck wheels. Since standard snap-in rubber valves are still used for these applications, it is important that the owners of these systems let their tire installer know that the vehicle is equipped with a direct system banded to the wheel before they change the tires.
Tire Rack works with wheel manufacturers to develop aftermarket wheels that accommodate direct tire pressure monitoring sensors/transmitters. This results in our ability to offer a wider selection of aftermarket alloy wheel styles that accept Original Equipment direct system components. Additionally, the Tire Rack\'s fitment specialists have carefully determined which aftermarket wheels will be compatible with the vehicle and system installed for customers purchasing Tire & Wheel Packages or wheel upgrades. Search results include notes regarding TPMS sensors and sensors can confidently be purchased online with wheels.
3.2 Indirect Monitoring Systems
In the interest of providing a lower cost Original Equipment system, indirect tire pressure monitoring systems were developed by vehicle manufacturers wishing to comply with the law while minimizing development time and cost. Indirect systems use the vehicle\'s anti-lock braking system\'s wheel speed sensors to compare the rotational speed of one tire to that in another position on the vehicle. If one tire is low on pressure, its circumference changes enough to roll at a slightly different number of revolutions per mile than the other three tires. Reading the same signal used to support ABS systems, the vehicle manufacturers have programmed another function into the vehicle\'s on-board computer to warn the driver when a single tire is running at a reduced inflation pressure compared to the others.
Unfortunately, indirect tire pressure monitoring systems have several shortcomings. Indirect systems won\'t tell the drivers which tire is low on pressure, and won\'t warn the driver if all four tires are losing pressure at the same rate (as occurs during the fall and winter months when ambient temperatures get colder). Additionally, our current experience with indirect systems indicates that they can generate frequent false warnings. We have found that false warnings may occur when the tires spin on wet, icy and snow-covered roads. In these cases, the false alarms would train the driver to disregard the tire pressure monitoring system\'s warnings, negating its purpose completely.
3.3 Working of TPMS
As its name suggests, a tire pressure monitoring system is more than a single part. In fact, TPMS involves a valve and a sensor, and it\'s also important to know that not all TPMS systems are created equal.There are two kinds of TPMS technology–indirect and direct. Indirect TPMS approximates tire pressure indirectly by using data from the vehicle\'s antilock brake system (ABS). Direct TPMS provides a more accurate calculation of your tire pressure using data gathered directly from a sensor placed inside each tire.
In either case, if a tire is detected to be underinflated by 25% or more, an alert lights up on your dashboard. But with direct TPMS, drivers are alerted sooner and–if the car is equipped with the four-tire TPMS display–can even see readings for each tire. One of the largest downsides of an indirect TPMS system is that it cannot detect when all four tires are low in pressure, which can happen quite frequently if tire pressure is not checked on a regular basis.
3.4 Concerns related to TPMS
Percentage of under-inflation that the law permits before warning the driver. The driver of a passenger car that calls for 35 psi may not be warned about tire pressure loss until it drops to 26 psi depending on the type of monitoring system used. Under the same circumstances, a driver of a light truck that calls for 80 psi won\'t be warned until just 60 psi remains. In both of these cases, significant load capacity has been sacrificed before the driver is warned.
The only way to overcome this obstacle would be to fit significantly over-sized tires to every new vehicle that could compensate for a 25% loss in tire pressure before becoming overloaded. Unfortunately, these larger tires would add to gross vehicle weight, generate more rolling resistance and increase the vehicle\'s aerodynamic drag. This would result in a loss of fuel economy and increased gasoline consumption in direct contrast to the government\'s Corporate Average Fuel Economy (CAFE) requirements for cars and light trucks.
While the legislation is well intended, we feel that direct tire pressure monitoring systems are the better means to warn the driver of low tire pressure before inconvenience becomes calamity. Additionally, we are concerned that the drivers of vehicles equipped with any tire pressure monitoring system will become over confident in the capabilities of their system and will be even less likely to confirm their vehicle\'s cold tire pressure with a pressure gauge at least once a month and before long trips.
3.5: TPMS Block Diagram
Fig. 3.2: Block Diagram of TPMS
Chapter 4: Introduction to MATLAB
MATLAB (matrix laboratory) is a multi-paradigm numerical computing environment and fourth-generation programming language. A proprietary programming language developed by MathWorks, MATLAB allows matrix manipulations, plotting of functions and data, implementation of algorithms, creation of user interfaces, and interfacing with programs written in other languages, including C, C++, C#, Java, Fortran and Python.
Although MATLAB is intended primarily for numerical computing, an optional toolbox uses the MuPAD symbolic engine, allowing access to symbolic computing abilities. An additional package, Simulink, adds graphical multi-domain simulation and model-based design for dynamic and embedded systems.
Fig 4.1: Matlab logo
Fig 4.2: Matlab Home Screen
4.1 Introduction to image processing
Image Processing is processing of images using mathematical operations by using any form of signal processing for which the input is an image, a series of images, or a video, such as a photograph or video frame; the output of image processing may be either an image or a set of characteristics or parameters related to the image. Most image-processing techniques involve treating the image as a two-dimensional signal and applying standard signal-processing techniques to it. Images are also processed as three-dimensional signals where the third-dimension being time or the z-axis.
There are five types of images in MATLAB.
1. Grayscale. A grayscale image M pixels tall and N pixels wide is represented as a matrix of double datatype of size M×N. Element values (e.g., MyImage(m,n)) denote the pixel grayscale intensities in [0,1] with 0=black and 1=white.
2. Truecolor RGB. A truecolor red-green-blue (RGB) image is represented as a three-dimensional M×N×3 double matrix. Each pixel has red, green, blue components along the third dimension with values in [0,1], for example, the color components of pixel (m,n) areMyImage(m,n,1) = red, MyImage(m,n,2) = green, MyImage(m,n,3) = blue.
3. Indexed. Indexed (paletted) images are represented with an index matrix of size M×N and a colormap matrix of size K×3. The colormap holds all colors used in the image and the index matrix represents the pixels by referring to colors in the colormap. For example, if the 22nd color is magenta MyColormap(22,:) = [1,0,1], then MyImage(m,n) = 22 is a magenta-colored pixel.
4. Binary. A binary image is represented by an M×N logical matrix where pixel values are 1 (true) or 0 (false).
5. uint8. This type uses less memory and some operations compute faster than with double types. For simplicity, this tutorial does not discuss uint8 further.
Grayscale is usually the preferred format for image processing. In cases requiring color, an RGB color image can be decomposed and handled as three separate grayscale images. Indexed images must be converted to grayscale or RGB for most operations.
Linear filtering is the cornerstone technique of signal processing. To briefly introduce, a linear filter is an operation where at every pixel xm,n of an image, a linear function is evaluated on the pixel and its neighbors to compute a new pixel value ym,n.
Fig 4.3 Linear filter
A linear filter in two dimensions has the general form
ym,n = ∑j∑k hj,k xm−j,n−k
where x is the input, y is the output, and h is the filter impulse response. Different choices of h lead to filters that smooth, sharpen, and detect edges, to name a few applications. The right-hand side of the above equation is denoted concisely as h'∗'x and is called the “convolution of h and x.”
Chapter 5: Non Invasive Tyre Burst Prevention System
Non invasive tyre burst prevention system compares area of radials and deduces wheather the tyre difference falls between safe range or not.
Fig. 5.1: Sample Image
• Converting image to grayscale
• remove all object containing fewer than 30 pixels
• fill gap
• fill any holes, so that ‘regionprops’ can be used to estimate the area enclosed by each of the boundaries
Fig 5.2: Converting RGB to gray, binarize and fill holes
• Display the label matrix and draw each boundary
Fig 5.3: Label Matrix
• loop over the boundaries
• obtain (X,Y) boundary coordinates corresponding to label \'k\'
• compute a simple estimate of the object\'s perimeter
• obtain the area calculation corresponding to label \'k\'
• compute the roundness metric
• display the results
• mark objects above the threshold with a black circle
Fig 5.4: Loop over boundaries
• Binarize image using adaptive filter and changing sensitivity
Fig 5.5: Image processes using adaptive filter
• remove all object containing fewer than 30 pixels
Fig 5.6: Removing all objects fewer than 30 pixel
• fill gap using the pen\'s cap
• fill any holes, so that regionprops can be used to estimate the area
• draw each boundary
Fig 5.7: Detecting boundaries
• loop over the boundaries
Fig 5.8: Boundaries detected
Step IX: Result Array
Fig 5.9: Resultant array
Chapter 6: Conclusion
40% of the vehicular accidents, which left many people dead and several others injured, have been due to tyre bursts. Out of these nearly 60% was due to incorrect tyre pressure. Incorrect tyre pressure leads to overheating of tyres and cause bursts. Due to advancement in automobile technologies, we have developed power steering that feels light even if the air pressure is less in car. In case of accidents, one gets seconds to react, which often leads to deaths.
Chapter 7: References
1. http://www.michelinman.com/pax/ PAX system description on Michelinman site
2. Minister Chung, Jung-hwan. \"The Ministry of Land, Transport and Maritime Affairs\" (PDF). Revisions to the Korean Motor Vehicle Safety Standards (KMVSS). The Ministry of Land, Transport and Maritime Affairs, Korea.
3. http://www.niradynamics.se/scripts/newsletter.php?id=55 TPMS mandatory in even more countries
4. http://www.elektronikpraxis.vogel.de/sensorik/articles/172243/ Reifendruck voll unter Kontrolle
5. Sean Phillips (2014). ss\"Achey Breakey Parts: TPMS And Corrosion\". ABOUT.COM. Retrieved 15 Oct 2014.
6. \"Real-World TPMS Tips & Tricks\". Tire Review. Babcox Media, Inc. August 23, 2013. Retrieved 17 Oct 2014.
7. \"Ride-On TPS Tire Sealants and Tire Pressure Monitoring Systems (TPMS)\". Retrieved 15 Oct 2014.
8. \"Faqs: Is Slime TPMS Safe?\". 2012. Retrieved 15 Oct 2014.
9. \"Convenient tire sealants to fix a flat tire; Evaluations show that compressor kits are better than aerosol sealers\". Retrieved 15 Oct 2014.
10. \"Common TPMS Service Questions and Answers\". July 16, 2012. Retrieved 15 Oct 2014.
11. Schneier, Bruce (2008-04-10). \"Tracking Vehicles through Tire Pressure Monitors\". Schneier on Security. Retrieved 2014-12-10.
12. 49 CFR, Ch. V., FMVSS No. 138, 2006
13. One of those studies is listed in the article \"An Evaluation of Existing Tire Pressure Monitoring Systems, U.S. Dept. of Transportation, DOT HS 809 297.\"
14. Another NHTSA study below tried to define acceptance procedures for tire pressure monitoring for this vehicle class. Grygier, Paul and Samuel Daniel, Jr., National Highway Traffic Safety Administration and Richard Hoover and Timothy Van Buskirk, Transportation Research Center Inc., June 2009, Testing Of Heavy Truck Tire Pressure Monitoring Systems (TPMS) In Order To Define An Acceptance Procedure, 21st International Technical Conference on the Enhanced Safety of Vehicles, Paper No. 09-0551.
15. Daniel, S. 2005. Status of TPMS Rulemaking, SAE Government/Industry Meeting - May 10, 2005
...(download the rest of the essay above)