Mj Investigations Blog

Vehicle Lamps ~ On or Off in a Traffic Crash?

Dec 13, 2016
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Witness and Victim Profiles

Feb 21, 2016
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Using sun and moon calculators in your investigation.

Jan 15, 2016
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Human Trafficking Task Force of Southern Colorado

Jan 9, 2016
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Traffic accident investigation and reconstructions can determine liability in the event of a traffic collision. Each day across the United States, people and machines react unexpectedly, causing thousands of traffic accidents claiming lives or causing permanent injuries. Of the over 6 million police reported traffic accidents in 2014, there were 29,989 fatal traffic accidents resulting in 32,675 fatalities in the U.S. Colorado alone had 544 fatalities in 2015, a rise of 56 fatalities over the 488 reported in 2014. Over 2 million people were injured with an economic loss estimated at over $242 billion.

When a traffic accident occurs, it is often not enough to simply say that something went wrong. A traffic accident investigation and traffic accident reconstruction can determine exactly what happened and can help prevent future traffic accidents. Additionally, traffic accident investigators can provide expert testimony in trials to hold the correct party accountable for the damage incurred by the traffic accident.

So why are people referring to a traffic “accident” as a “traffic crash”? According to the Merriam-Webster dictionary, an “accident” is defined as an unexpected and undesirable event, especially one resulting in damage or harm. Basically an unforeseen incident. A “traffic crash” is defined as colliding violently or to strike against something with great force, causing damage or destruction, or cause something such as a car to strike against something in this way.

The difference between an “accident” and a “crash” is an “accident” implied something that was out of your control and unavoidable whereas a “crash” describes a violent collision. A person who causes a traffic accident could have avoided the incident based on their decisions. It may as well mean for some unexplained reason, forces of the universe have met at a certain point in time and place and a result occurred that defies explanation. It means that it has likely never happened before and will probably never occur again in the future.

 

Why Do You Need A Traffic Accident Investigator?

There are plenty of reasons why people turn to Traffic accident investigation:

  • To determine what caused a traffic accident and prevent traffic accidents in the future.
  • If you don't know what really happened in a traffic accident, you may be liable for damages and injuries. A good traffic accident investigator can prove that you were not at fault, save you long court hassles and thousands of dollars.
  • To get answers. Sometimes, just knowing what really happened brings a sense of closure. A traffic accident reconstruction can tell you what really happened in a specific situation.
  • To get evidence that can stand up in court. If you're trying to collect claims for a traffic accident or need to prove that you did not cause a traffic accident through negligence or other fault, only a qualified traffic accident investigator can help you get the evidence you need to solidify your court case.

 

What Happens In A Traffic Accident Investigation?

The police will investigate a traffic accident with the intention of determining if any criminal action took place in the traffic accident. Some of the things the police look for are speeding, hours-of-service violations, mechanical violations, alcohol use, drug use, etc. For example, if a truck driver is exceeding his hours of service and causes a serious traffic accident because he fell asleep at the wheel, he will likely be criminally charged. If that traffic accident results in a fatality, the charge will likely be vehicular homicide.

Depending on the nature of the traffic accident, a traffic accident investigation can include visits to the accident site as well as interviews with witnesses and with those involved. A traffic accident investigator will attempt to re-create exactly what happened so they can see exactly what took place and how. Today, this often is done with a variety of computer software programs. A traffic accident investigator may collect testimonies and other evidence, such as measure and document the scene with photographs and notes, that can help you determine exactly what happened in a traffic accident.

During the reconstruction stage, investigators will examine the point of impact, final resting positions, skid marks, scrub marks, and gouge marks. Electronic surveying equipment is typically used during this stage to recreate the traffic accident. The investigators may also inspect each vehicle beyond the damage it has suffered. Checking components like brakes, steering, tires, suspension, and lights may shed light on the cause of the traffic accident.

Why You Need an Traffic Accident Reconstructionist?

January 12,

Traffic accident investigators reconstruct collisions for several reasons. The most important and yet more subtle reasons for looking into significant collisions is to identify any environmental factors that may have been a primary contributor to the collision. This may prevent additional collisions at a certain location from causing further injuries or fatalities. They are often the most easily and quickly remedied. Another benefit for examining these collisions is to identify any safety concerns in vehicles for equipment or structural failures. Although this prevents further unwarranted injuries or fatalities, these are less common and more difficult to see through to the end. Lastly, there is the investigation to determine fault or liability.

Often in vehicle collisions, the events can be foreseen, although not always observed. They can certainly be explained and liability assigned. This happens daily in every city. In order to explain how an event occurred and why, a reconstructionists must seek causation. In doing so, contributing factors need to be considered in determining causation. These factors may include driver behaviors, environmental factors, and vehicular factors.

Once a roadway hazard is perceived by a driver, the driver reacts to the hazard, and physics takes over. There is one of two outcomes as a result. There is a collision or a collision avoidance. In the case of a collision, there is a multitude of factors that affect the outcome of the impact. The investigator must consider acceleration, braking, speed, friction, and direction, energy and momentum, all of which has to be carefully analyzed. An effective reconstructionist has the unique ability and fortitude to compute many of these factors based on roadway evidence, scaled measurements, and sometimes recorded data.

Traffic Accident Reconstructionists are uniquely trained to take the investigation further into causation factors. Investigators consider many factors prior to and after the collision, as well as, being trained to meticulously explain the details of a collision itself, where more events occur in 1/10th of a second than most can imagine.

For example, in a scenario where two vehicles collide at an intersection, a reconstructionist is interested in the pre-collision events. Where were the drivers traveling from? Where was their intended destination? What was their frame of mind at time of departure? What do the cell phone records reveal prior to the collision? In addition, and all too often, were the driver’s intoxicated?

Once these questions can be answered, the next issue at hand is the scene of the collision. Hopefully, this is where the responding police department has protected the scene for preservation of evidence and, subsequently, conducted a thorough investigation by obtaining all possible witness statements, marked any and all roadway evidence, and successfully measured the scene using a total station or other scene mapping equipment. These and others are all vital requirements for a successful private practice reconstructionist to review the case and identify any factors that may be important to a civil or criminal case. One rule to keep in mind is there is very seldom evidence not tampered with from bystanders or other emergency personnel whose primary job is not to preserve evidence but save lives.

While reviewing the results of the investigation or revisiting a scene, a reconstructionist must look for environmental factors such as was the sun at a position to blind a driver’s view, are there trees or other objects blocking a view of traffic, was the traffic regulating equipment working properly. We can then begin to look at the roadway makeup and condition at the time of the collision. Another factor to consider is contributing vehicle factors by the units involved. Are there any vehicle recalls and have the repairs been completed by an approved mechanic? Have there been any recent collisions that may have caused prior damage to a vehicle that made this specific wreck worse than it should have been? Was the vehicles equipment operating properly at the time of the collision?

In addition to these telling details is the vehicle damage. There is a very accurate story told by the damage that often cannot be altered. The principle direction of force (or PDOF) will fold a vehicles exterior in the direction the collision occurred.

 

Traffic Accident Reconstructionists can also tell which lights were on during a collision, even if they are off once the collision occurs (an affect called “hot shock”).

 

In the case of law enforcement investigations, often a driver who wishes to avoid the fact that he was driving can be identified by a foot print left on a brake or accelerator pedal. A Traffic Accident Reconstructionist must look at how law enforcement identified a person as the driver so appropriate liability can be assigned.

 

Why hire an ACTAR accredited reconstructionist?

ACTAR is a term frequently seem when looking for a Traffic Accident Reconstructionist. So exactly what is an ACTAR accredited reconstructionist? ACTAR is an acronym for the Accreditation Commission for Traffic Accident Reconstruction, an internationally recognized commission with more than 1260 ACTAR Accredited Reconstructionists practicing throughout the United States, Canada, Australia, Singapore and the United Arab Emirates.

From their website, ACTAR was founded by and exists for the benefit of the traffic accident investigation and reconstruction community, as represented by the membership of the participating professional organizations.

 

Since its incorporation in 1991, it has been the ongoing goal to promote, within the legal and scientific community, a recognition of the minimum standards established by the NHTSA study, as well as those developed by an ongoing review of the latest technology and trends in the profession.

 

Minimum standards have been designed to advance the recognition of the ACTAR accreditation program, and to encourage the integrity, consistency and professionalism of those involved. ACTAR aims to promote the professional and intellectual development of those individuals, organizations and institutions involved in traffic accident investigation and reconstruction and to assist the legal and scientific community in weighing the suitability of individuals offering their services as Traffic Accident Reconstructionists.

 

So how does a Traffic Accident Reconstructionist become accredited?


A reconstructionist must apply to the commission and meet minimum standards of education and experience. If the standards are met, the reconstructionist must successfully complete a practical and a theoretical examination to be accredited.

 

The examination consists of two parts, a Theory portion and a Practical portion. The Theory portion consists of 75 questions drawn from areas such as Kinetic Energy, Conservation of Momentum, Time-Distance Evaluations, Physical Evidence from the road and vehicle, Photography, Lamp Analysis and Airborne Analysis.

 

The Practical portion is a staged collision where the candidate is supplied with photographs of the scene and involved vehicles, vehicle data and damages, location and type of physical evidence and a skeleton diagram. The candidate is asked to provide impact and departure speeds, angles, Delta-V for each vehicle and identify specific physical evidence.

 

Although participation in the accreditation program is voluntary, people who are properly trained and experienced in Traffic accident investigation and reconstruction can successfully complete the examination and achieve accreditation. Those accredited must obtain a minimum number of continuing educational units (CEUs) over a five-year period from completion of the initial examination to maintain their status with ACTAR.

 

An ACTAR accredited reconstructionist has demonstrated their training and knowledge before a peer group organization and must maintain a high level of training and experience top become accredited and to maintain their accreditation.

 

By hiring an ACTAR accredited reconstructionist, one is assured that the individual follows the highest standards of training and the ACTAR Code of Conduct to provide an unbiased, efficient and compete traffic accident reconstruction available.

 

Mj Investigations, LLC. offers an ACTAR accredited reconstructionist (ACTAR #1084) with over 35 years of experience. Accredited since the year 2000, Mj Investigations Traffic Accident Reconstructionist will provide the training and experience of investigating and reconstructing thousands of traffic accidents in five states and providing expert testimony.

 

As you can see, a solid collision investigation can fill a large file of detailed reporting by someone who has received the proper training and has obtained the right experience for the needs of a client. Mj Investigations, LLC investigators have responded on scene to thousands of collisions, many fatal, and have had the unique opportunity to observe the evidence minutes after the collision has occurred. Mj Investigations, LLC investigators have law enforcement backgrounds, experienced in civil depositions and testimony, as well as, successful criminal cases.

A physicist or an engineer can calculate data or explain the damage to vehicles based on principles and graphs, but Traffic Accident Reconstructionist have the first-hand experience that gives clients the edge in a successful case. Mj Investigations, LLC training has come from nationally prominent authorities in the field of traffic accident reconstructions and investigations and our experience has come through being at the scene of every type of incident our clients may incur from single vehicle to a passenger car vs. commercial vehicle. If there is a need for commercial vehicle inspections, Mj Investigations, LLC is able to provide them when needed for an investigation at varying levels. In addition, Mj Investigations, LLC has the availability to image event data recorders to obtain collision information such as seat-belt use, braking indicators, speed, airbag deployment, and much more.

 

 

 

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What does drag factor or coefficient of friction mean?

The term “Drag Factor” is utilized in traffic accident reconstruction. This term is not mentioned in engineering mechanics or physics books. Drag Factor is the deceleration coefficient for an entire vehicle. The Coefficient of Friction is the deceleration coefficient for a sliding tire. The Drag Factor and Coefficient of Friction are the same, if and only if, all four tires on a motor vehicle are locked and sliding on a level surface.

 

For years police officers have been taught these two terms were the same thing and for the sake of simplicity, we will use the terms interchangeably and say they mean the same thing for the purpose of this discussion. In this article, the drag factor, or coefficient of friction, basically measures the stickiness of a surface such as a roadway, a grass knoll, a ditch, and the like.

 

So why does an accident investigator need to know what the drag factor of a roadway surface is and how do they use it? Each surface has its own drag factor, which will determine how quickly a vehicle can come to a stop and how far it will travel while doing so. This answers the question; “How fast were they going?” Probably the most common question heard when an accident investigator is retained for a case.

 

In an accident investigation, this stickiness of a surface is assigned a number and is denoted with an f. Drag factors can be determined a number of ways. The use of tables and charts published by accident-investigation authorities, and based on thousands of tests, is the most common.  These charts have been validated in court and are used worldwide. They are available from a number of sources, both in print and online.

 

The use of a drag sled is also common. A drag sled is basically a box that is a known weight; it is pulled at a known force, and the drag factor of the surface can be calculated. These devices can be purchased premade, or they can be made by the investigator. 

 

A skid test using a similar vehicle, if possible, can be completed. The vehicle is driven at a known speed, and then a hard-braking maneuver is completed to obtain skid marks. These skid marks are measured, and a drag factor can be calculated.

 

Various scientific instruments (for example, the VC-3000) can be used to determine the drag factor of a roadway surface. These devices began in the research field and the drag racing world and can be purchased for about $1,500.

 

Knowing the coefficient of friction of a roadway is important as this factor will affect the accuracy of the speed calculation. Let’s take a simple example of a vehicle sliding on the roadway. The vehicle left 4 skid marks that were measured and an average skid of 200 feet was determined. The investigator presumed the roadway was new asphalt and decided it had a coefficient of friction of 0.8 by using the standard chart of coefficient of friction for various roadway surfaces. Using the basic slide to stop formula and the investigator’s coefficient of friction the minimum speed is calculated at 69.2 MPH.

It was later determined the roadway was actually, Portland cement that was over 10 years old and heavily traffic polished. Portland cement that I traffic polished has a coefficient of friction of around 0.55. Using this coefficient of friction the minimum speed is calculated at 57.4 MPH. A difference of aboout 12 MPH.

 

There are additioanl variables that will affect the calcualtions but this article is not about speed calculations. The investigator must keep this in mind and remember that an accurate coefficent of friction, or drag factor, is important when trying to determine how fast a vehicle was traveling prior to a traffic accident.

 

When is a Skidmark not a Skidmark?

Tire marks are probably the most often confused and misinterpreted of all roadway evidence. A tire mark is the general class of marks left by a tire, whether rolling or locked. A skid mark is left by a locked, sliding tire.

There are different types of tire marks associated with a traffic accident investigation. The most common a private investigator will observe are:

  • Scuffs: made by a rotating or yawing vehicle, a vehicle acceleration, or a flat tire
  • Yaw mark: made by a tire that is rotating and sliding sideways parallel to that wheel’s axle; also referred to as sideslip or critical-speed scuff marks
  • Skids: made by a locked wheel caused by the application of the brake
  • Prints: made by a rolling tire
  • Scrub mark: left by a wheel locked due to damage

Skid marks are further identified in the following ways:

  • Pavement grinding: caused by material embedded in the tire grinding along the surface of the roadway (can be hard to see)
  • Tire grinding: caused by the tire itself being ground by the abnormalities of the road surface (can also be hard to see)
  • Erasure: caused by a sliding and locked tire erasing or removing any loose materials from the road surface so that area appears clean (this is frequently seen but is the most commonly ignored skid mark)
  • Squeegee: caused in a similar way as erasure and removing moisture
  • Soft foreign-material smear: caused when snow, mud, or soil that has been smoothed or spread
  • Bituminous material smears: caused when a tire is hot enough to smear tar and asphalt (the most commonly measured segment is referred to as a skid mark)
  • Tire smear: caused when a tire is hot enough to smear the rubber from the tire; usually seen on concrete surfaces
  • Shadow: the part of a skid occurring prior to any pavement grinding; supposedly always present; more often than not extremely difficult to detect; and almost always very difficult to document or image
  • Skip skids: caused by deformities in the road surface, or a vehicle weight shift
  • Gap skids: caused when releasing and reapplying brakes during a skid
  • Furrow: caused by a sliding, non-rotating wheel creating a plowed depression in soft material so that material furrows on each side; no tire print is visible
  • Rut: caused by a rolling tire in soft material; the tread pattern is usually visible
  • Acceleration marks: typical scuff mark made when sufficient power is supplied to the driving wheels and at least one-wheel spins on the roadway surface; begins as a J-shaped mark, caused by initial fishtailing as the tires heat and seek traction; the beginning of the scuff is usually very dark, and the mark gradually disappears
  • Roadway art: produced when drivers back up and then shift gears to move forward before they have stopped going backward
  • Flat tire scuffs: made by a seriously underinflated or overloaded tire; a partially deflated tire produces marks that are heavy on the edges and light in the middle; with a completely deflated tire, the sidewall touches the roadway, causing scalloped and wavy marks, and rim cuts are commonly seen.
  • Scuff Mark: a tire mark from a wheel that is both rotating and slipping: acceleration scuffs, yaw marks, flat-tire marks.
  • Scrub Marks: a skid mark caused by the vehicle being redirected as a result of a collision; marks generally look like irregular shaped smears and are characteristic of the point of impact

The proper identification of tire marks is an important part of an accident investigation. Each tire mark is produced by a specific action of the vehicle during the traffic accident event. Tire marks can tell the private investigator about what a driver did or attempted to do prior to and after a collision. A point-of-impact (POI) or an area-of-impact (AOI) can determined which is an extremely important part of the traffic accident investigation.

The proper interpretation of tire marks can tell the private investigator which, of the many, speed calculation formula to be used. For example, a vehicle left a 150-foot tire mark on a paved roadway prior to running off the road. If the tire mark is identified as a yaw mark and the specific formula for that type of mark is used, a speed calculation of 48 mph is determined. That same mark if identified as a straight skid will yield a speed of 56 mph. An 8-mph difference may not mean much unless the posted speed limit is 40 mph.

 

Collision-Avoidance Systems

 

Once in the realm of science fiction, it seemed incredible that a vehicle would be able to “see” other vehicles or pedestrians, anticipate collisions, automatically apply the brakes or take corrective steering actions and even drive itself. But this advanced technology is becoming increasingly available and more cars can do this to some degree.

 

Some of these systems have been around for a few years, mostly on high-end luxury cars. Collision-avoidance systems are getting better and are rapidly becoming a standard addition to new cars and not just a high-end option.

 

The Insurance Institute for Highway Safety (IIHS) has added collision-avoidance system testing to its suite of safety evaluations. They have determined that some of these collision-avoidance systems could prevent or mitigate many crashes. To win a top overall safety score, a car needs to have a forward-collision warning system with automatic braking and any autobrake system has to function effectively in formal track tests. To view the test results or to check if a vehicle has collision-avoidance systems available, visit the IIHS website at: www.iihs.org/iihs/ratings/crash-avoidance-features.

 

National Highway Traffic Safety Administration (NHTSA) is considering making some collision-avoidance systems mandatory. NHTSA’s 5-Star Safety Ratings note which systems are available on cars they crash-test but their presence doesn’t affect the rating. The cost of collision-avoidance systems can still be an obstacle with most advanced systems being part of a large options package or on a model’s higher, more expensive trim versions. The options can add thousands of dollars to a vehicle’s price.

 

 

Lasers, Radar, and Cameras

 

These active safety systems rely on numerous sensors, cameras, lasers, and short- and long-range radar which monitor what is going on around the vehicle. Other vehicles, pedestrians, cyclists, as well as the vehicle itself and even road signs are all monitored. Data is processed by computers, which then prompt an action from the car or the driver. These actions may start with attention-grabbers, such as a beep, a flashing dashboard icon, a tug from the seatbelt, or a vibration in the seat or steering wheel and if the driver doesn’t respond, the more advanced systems then apply partial or full braking force. Research has found that when a warning system emits too many inappropriate alerts, then there is temptation to switch it off.

 

Not every system on the market today is top-notch. But there’s a net benefit regardless. Even if the systems fail to prevent a crash, that crash is going to be less severe than it would have been otherwise. These systems can prevent crashes from happening in the first place.

 

Adaptive Cruise Control (ACC)

 

ACC allows the driver to select the cruise control speed and following gap. ACC detects if there is a vehicle in your path and either accelerate or brakes to maintain the selected following distance. If ACC cannot apply sufficient braking because of approaching a vehicle too rapidly, ACC will alert the driver.

 

Rear cross-traffic alert

 

Cross-traffic alert warns you of traffic approaching from the sides as you reverse. The warning usually consists of an audible chirp and a visual cue in either the outside mirror or the rear camera’s dash display. The more advanced systems can also pick out bicycles and pedestrians.

 

Forward-collision warning (FCW) and autobrake

 

Also called a pre-crash warning system, these systems warn drivers of an impending collision by using visual, auditory, or physical cues. Most vehicle systems also pre-charge the brakes and take other steps to prepare for impact. If the driver ignores the warnings, systems with autonomous braking, or autobrake, will apply partial or full braking force. They can be active at anywhere from walking to highway speeds.

 

Blind-spot monitoring (BSM) and assist

 

A blind-spot monitoring system uses radars or cameras to scan the areas beside and behind you, looking for vehicles entering or lurking in your blind zones. When such a vehicle is detected, an illuminated icon appears in or near the appropriate side-view mirror. If you signal a turn while a car is in your blind zone, some systems send a stronger alert, such as a blinking light or louder chirps. More advanced systems help keep you in your own lane by applying the

brakes on one side of the vehicle.

 

 

Pedestrian detection and braking

 

Pedestrian detection can recognize a person straying into a vehicle’s path. Some will automatically apply the brakes and newer systems can also detect bicyclists.

 

 

Adaptive headlights

 

As you turn the steering wheel adaptive headlights will swivel, which helps illuminate the road when going around curves. Adaptive headlights improve a drivers’ reaction times by about a third of a second, just enough to avoid hitting a parked car or animal on a dark road.

 

Lane departure warning (LDW) and assist LDW

 

These systems use a camera, along with various sensors, to identify lane markers and monitor your distance from them. If you stray over the line without signaling, you’ll hear a warning tone, an LDW warning in the instrument panel or perhaps a physical alert like a vibration in the steering wheel or seat.

 

Lane departure warning does not provide a warning to help avoid a cash unless it detects the lane markings. More advanced “lane keeping assist” (LKA) systems selectively apply brakes or nudge the steering to guide you back if you’re wandering.

 

 

Automatic park assist

 

The system will identify a parallel or perpendicular parking space your car can fit into. Once found, the system steers the car into the space; some can also exit from parallel parking

spaces. The driver still does the braking and has to follow commands from the system.

 

 

Rear cameras and parking assist

 

 

Rear-view cameras will be mandatory with the 2018 model year. They can help prevent a back-over accident, such as hitting a child who wanders behind your car. Parking assist sensor systems notify you with progressively louder and quicker beeps as you close in on an obstacle.

 

  1. View displayed by the camera.
  2. Corners of the rear bumper.

 

Knowing what collision-avoidance systems a vehicle may have and what they are designed to do is within the realm of the private investigator. Due to the growing list of collision-avoidance systems the investigator must consider this advanced technology as part of their investigation. By researching the vehicle involved, the investigator can determine the type of systems a vehicle is equipped with. Understanding what the systems are designed to do can assist the investigator in discovering other factors involved in a traffic accident. These questions can become important for the client or the attorney.

Questions for the investigator to consider include:

  • What is the vehicle equipped with?
  • What is the system designed to do?
  • Did the system work properly?
  • Was the driver provided a warning of the potential hazard?
  • Did the driver respond to that warning?

The investigator can check the IIHS website: www.iihs.org/iihs/ratings/crash-avoidance-features or contact the local vehicle manufacture dealership to get information about the systems a vehicle may have and what they are supposed to do.  

 

Contact Us Today!

To schedule an appointment or find out more about the services we offer, please call  our Colorado Office at (719) 694-6343 or our Maine Office at (207) 495-3750. You can also send us an email at info@mji.expert or use our contact form.

News & Events

Mj Investigations releases second edition of our popular book; "Accident Investigations for the Private Investigator and Attorneys". Order your copy now.

Mj Investigations open Maine office serving the New England states.

Check out our articles for PI Now. 

https://www.pinow.com/articles/2348/traffic-accident-investigations

 

Our second article has been posted on PI Now. https://www.pinow.com/articles/2349/accident-investigations-vehicle-lamp-examinations

 

View our latest article on tire marks and their use in accident investigations at: https://www.pinow.com/articles/2399/tire-marks-their-role-in-accident-reconstruction-investigations

Our latest article on PI Now.

https://www.pinow.com/articles/2484/accident-investigations-determining-speed-using-drag?signup_code=roundup

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