The skid mark is a visible sign left by any solid object moving against another, and is an important aspect of tracking evidence analysis in forensic science and forensic engineering. Signs of scars caused by tires on the road occur when the wheels of the vehicle stop rolling and gliding or spinning on the road surface. Used marks can be analyzed to find maximum and minimum vehicle velocities before impact or incident. Extraction may also occur on black or diesel ice deposits on the road and may leave no traces at all.
Video Skid mark
Characteristics
Skid marks are divided into "acceleration marks" made on acceleration, if the machine provides more power than the tires can transmit; "Braking marks," if the brakes "lock" and cause the tire to slide; or "yaw sign", if the tire shifts sideways. Each skid mark has a distinctive appearance, and an experienced crash engineer or forensic engineer can often determine what a vehicle is doing by checking the mark left by the tire.
Contrary to popular belief, the skid marks are not caused by rubber cuts from tires that are deposited on the road due to friction heating the tires. The actual skid is bituminous oil on the asphalt that is heated because friction breaks or accelerates and rises to the surface, leaving a dark marker. This is why the signs are fading. Within an hour, 3-4% of the marks have faded.
Braking signs will vary depending on whether the car is using ABS or not. Otherwise, there will be two paths. The darker mark on the outside is from the front wheels, while the rear tires leave thinner marks. This is because the given force makes the wheel take the shape of a cone. If the car uses ABS, the sign will be dimmer because less heat is generated by the ABS stop-stop mechanism. Scratch marks may be visible but with ABS.
Maps Skid mark
Stair case
Used marks may also form where the ladder suddenly slips and the user falls to the ground, especially if the foot of the stairs is damaged or absent. The loss of foot or rubber leg causes the aluminum stile to come into contact with the ground, and if hard surfaces such as concrete or tiles, skid marks show how and why the ladder slips. Unless sticking to the wall where they lean, the ladder can slip easily, especially if the ladder is leaning at an angle lower than about 75 degrees. Such slip accidents tend to occur when the user is near the top of the ladder, increasing his chances for serious personal injury.
Accident reconstruction
These marks are important evidence for the reconstruction of vehicle accidents, when their size and shape can reveal much about vehicle speed and the strength of acceleration or deceleration. They are one form of trail evidence. They represent the proof of contact produced in accordance with the principle of the Locard exchange. The skid mark is usually closely related to the vehicle's speed during braking, so measuring the mark yields the original speed estimate.
See also
- Braking distance
- Forensic Materials Engineering
- Engineering of forensic polymers
- Degradation polymers
Note
References
- Introduction to Forensic Techniques (Forensic Library) by Randall K. Noon, CRC Press (1992).
- Investigation of Forensic Techniques by Randall K. Noon, CRC Press (2000).
- Forensic Materials Engineering: Case Studies by Peter Rhys Lewis, Colin Gagg, Ken Reynolds, CRC Press (2004).
External links
- Accreditation Commission for Traffic Accident Reconstruction (ACTAR)
- National Highway Traffic Safety Administration
- National Academy of Forensic Engineers
Source of the article : Wikipedia
0 Comments