Tire Marks Research Articles

Thermal Engineering Analysis of Rubber Vulcanization and Tread Temperatures During Severe Sliding of a Tire

Abstract Tire skid marks at the scene of an accident are often used as evidence and are a very important phenomenon. However, the mechanism of this complex phenomenon has not yet been fully examined. Tires are manufactured by a chemical reaction in which rubber molecules are combined into a network structure during a process called vulcanization, in which the tire is heated in a mold. The transient temperature distribution is important in determining the state of vulcanization, but the analysis is very difficult. We treat the tire tread as a rubber slab to estimate the temperature history during heating and cooling. Then we calculate the vulcanization index using Arrhenius's equation, assuming that the rate of chemical reaction approximately doubles as the temperature increases by 10° C. Finally, we calculate the transient temperature distribution of the tread due to the heat generated by internal friction (rolling resistance of the tire), and the heat generated by sliding friction under conditions of severe cornering and braking. We investigate a criterion for modeling the occurrence of tire skid marks, assuming that skid marks are caused by exceeding the softening temperatures of the rubber and asphalt.

Estimating Truck's Critical Cornering Speed and Factor of Safety

Fully laden trucks are prone to rollover when exceeding a critical cornering speed. After an accident, authorities, both highway engineers and the police, often need to establish a vehicle's speed from tire marks and other physical evidence. This paper outlines the relative precision of equations of varying complexity used to estimate a truck's critical rollover speed based on tire marks. An error analysis is compared with a limited tachometer data base to evaluate the accuracy of the speed-estimating equations. The study shows that for most situations with fully laden, rigid trucks, the simple lumped-parameter model gives an acceptable estimate of the rollover speed for highway design engineers and the police. Also, a review of the lateral acceleration generated by a vehicle negotiating a minimum-radius curve found that the acceleration is very close to the level needed to tip over a truck. Based in part on these findings a method for developing a reasonable estimate of level of safety is discussed.

The calculation of motor car speeds from curved tyre marks

The technique of calculating speeds of cornering vehicles from the curvature of their tyre marks is widely used, although misgivings have been expressed over its accuracy, given the way that cornering ability depends on individual characteristics. Experiments have been performed in a range of motor cars to explore these effects, to establish the accuracy of the technique and to draw up a set of guidelines for accident investigators. The conclusions are that the marks must clearly indicate sideslipping and a degree of yaw by the vechicle; that the measurement of radius should be taken directly from the road surface; that only the first part of the mark (usually about 15 metres) need be measured; that the yaw of the vehicle should not be large; and that the speed so found should be reckoned as being that at the start of the marks ± 10%. The characteristics of an individual motor car may affect its ability to achieve a particular lateral acceleration without loss of control, but not the speed indicated by its tyre marks.

Spatial and temporal variability of some soil physical properties following tillage of a Nigerian Paleustult

The objective of this study was to evaluate quantitatively the magnitude of the spatial and temporal variation for 7 soil physical properties on a conventionally-tilled Nigerian Paleustult. A 0.4-ha plot was disc-ploughed, disc-harrowed twice, subjected to tractor-wheel traffic at regular space intervals and then seeded to maize ( Zea mays, L.). There were significant differences in the physical properties owing to tillage position (spatial variability) and date of sampling (temporal variability), more so in the 0–10-cm layer than in the 10–20-cm layer. In the surface layer, bulk density ( Db) and penetrometer resistance ( PR) were significantly higher ( P ⩽ 0.01) along the tyre marks (maximum Db = 1.76 Mg m −3) than in the uncompacted crop row (maximum Db = 1.35 Mg m −3) and interrow positions (maximum Db = 1.46 Mg m −3). Saturated hydraulic conductivity ( K sat), total porosity ( TP) and macroporosity ( M) were significantly lower along the tyre mark than in the crop row and interrow positions. K sat ranged from 0.6 to 42.8 cm h −1, TP, from 0.34 to 0.50 cm 3 cm −3 and M from 0.06 to 0.25 cm 3 cm −3 along the tyre mark and crop row positions, respectively. Significant temporal changes were noticed only in K sat, soil moisture content ( MC) and PR. K sat increased steadily with time along the tyre mark, but showed an irregular trend in the other two positions. PR did not change with time along the tyre marks but it increased significantly with time along the other two positions. MC changed according to the periodicity of rainfall. Only TP varied, owing to tillage position × date interaction. The 10–20-cm layer was spatially less variable but temporally more viarable than the surface layer. Only K sat and PR showed significant changes owing to the tillage positions, but Db, K sat, PR and moisture retained at 10 kPa suction ( τv10) showed significant temporal changes. Only τv110 varied owing to position × date interaction in this layer.

Review Lecture - Forensic science

The influence of the scientist in the investigation of crime has grown rapidly since the establishment of regional forensic science laboratories about 40 years ago. Eight laboratories with a staff of about 700 now cover the whole of England and Wales and a fictional crime of kidnapping is used to illustrate how the scientist can help the police officer in his enquiries. A broken window with smears of blood on it together with tiny fragments of fibres can a great deal of useful information and the methods of investigation is described; the car the criminals used is defined by an examination of smears of paint on a gatepost, tyre marks in soil and fragments of headlamp lens. The use of computerized information banks dealing with analytical characteristics and their use throughout the country is discussed, together with techniques available for examining traces the criminals may have brought to, or left at the scene. Unsolved problems in forensic science are considered.

Luminescence of Tyre Marks and Other Rubber Contact Traces

Transfer of luminescent or potentially luminescent contact traces from tyres and from rubber articles generally is a widespread phenomenon that can be exploited evidentially. The circumstances under which transfers occur and the factors governing detection and application of such evidence are discussed and illustrated.

Concrete Safety Barrier Design

The concrete safety barrier known as the Safety Shape is proving to be a major factor in preventing the highly dangerous, often fatal cross-median type highway accident. The design is also proving effective in reducing damage to both vehicle and barrier in the more numerous lesser-angle impact. More than 1,400 miles (2,254 km) of the Safety Shape barrier are now built or planned for the nation’s highways. Most of these installations have been made within the past 5 yr. The large number of tire scrub marks on barrier sections in use, without accompanying paint marks or accident reports to authorities, indicates that these involvements are being experienced without major damage to the vehicle, to its passengers, or to the barrier itself. Basic design features are described, including jointing requirements, reinforcement, and base restraints. The paper illustrates the excellent practical applications that are being made by construction agencies in adapting the shape to secondary uses in conjunction with other structures in the highway system.

Tyres and Crime

The need for accurate, comprehensive and speedy permanent records of tyre marks is emphasised. The significance of various features found in tyre marks is discussed, and the means by which the make of vehicle may be deduced from tyre marks are suggested. Features which enable a tyre mark to be related to a specific tyre are detailed. Reference is also made to the double transfer of tyre marks onto clothing and cloth marks onto tyres.

Traumatic Torsion of the Lung

In 1954, Stratemeier and Barry (1) reported what appears to be the first case of torsion of the lung following trauma recorded in medical literature. Their patient, a six-year-old boy who was struck by a vehicle, had a tire mark on the lower left chest. X-ray examination showed a curved, striated pattern extending from the left hilus upward to the left apex, with a partial pneumothorax bilaterally. Death occurred six hours after admission. At autopsy, the left lung was found to be rotated anteriorly, with its base assuming a superior position and its apex in an inferior position. The inversion was 180° about a transverse (coronal) axis through the left hilus. The curved, striated pattern represented the inverted vascular trunks supplying the lower lobe, then in the apex of the left thoracic cavity. The torsion was believed to have been brought about by the sudden compression of the left lower chest by the weight of the vehicle, causing displacement of the lower lobe cephalad. The sudden release of the pressure allowed the expanded upper lobe to move more caudad and occupy the space normally filled by the lower lobe. Recently, we observed a case of torsion of the lung which was strikingly similar to that of Stratemeier and Barry. On March 24, 1955, a seven-year-old white girl fell from a moving vehicle and a front wheel passed over the lower chest anteriorly. Examination, on admission to the emergency room of the Jackson Memorial Hospital, revealed a 2-inch laceration of the extensor surface of the left arm, fractures of the fourth to ninth left ribs, and a fracture of the left femur. The initial roentgenogram of the chest is shown in Figure 1. The physical findings suggested intra-abdominal bleeding, and an exploratory laparotomy was done twelve hours after admission. An extracapsular rupture of the spleen and retroperitoneal hemorrhage were found, and splenectomy was performed. Roentgenograms made on the second and third hospital days disclosed homogeneous clouding of the left chest, which was assumed to represent a massive hemothorax. Attempts at thoracentesis, however, were unsuccessful. Because of the patient's critical condition, management was by supportive therapy during the next six weeks. There was slow improvement during this period, but a low-grade fever persisted. Films continued to show a homogeneous density of the left chest. On May 4, a left thoracotomy was performed for decortication of the presumed organized left hemothorax. The surgeon, however, was unable to find a cleavage plane and broke through the visceral pleura. The lung tissue was necrotic and friable, and a pneumonectomy was therefore undertaken. At exposure of the hilus, the lung was seen to have rotated 180° in a clockwise direction, viewed from the lateral to the medial aspect. All structures of the lung root were included in the torsion.

Torsion of the lung following thoracic trauma; a case report.

Numerous cases of thoracic and pulmonary trauma are reported in the literature. Descriptions are to be found of pneumothorax, hemohydrothorax, atelectasis, pulmonary edema, interstitial and alveolar hemorrhage, ruptured alveoli, and ruptured bronchi. The following case is believed to be unique. On April 29, 1952, at 5:55 p.m., a six-year-old white boy was admitted to the Pediatric Ward from the Emergency Room. He had been struck by a vehicle approximately thirty minutes before admission, suffering a compound fracture of the right humerus and possible internal injuries. There were multiple abrasions, and a tire mark was evident over the left lower chest anteriorly. Roentgenograms of the right humerus, chest, and abdomen were immediately obtained. The fracture of the humerus was at the mid point of the shaft, comminuted and compounded. The flat film of the abdomen disclosed no unusual findings. The chest roentgenogram showed irregular clouding of the upper half of the right lung field with a peculiar striation pattern in the mid-portion of the left lung field. This striation extended from the hilus laterally and then swept upward in a curving fashion. Bilateral pneumothorax was present, most pronounced on the left. Several fractured ribs were seen on the left in the mid-portion of the chest (Fig. 1). Speculation as to the cause of the markings in the lung fields suggested a combination of pneumothorax with areas of atelectasis, pulmonary edema, and perhaps some hemorrhage within the lung tissue. The peculiar course of the striations on the left was not adequately explained. The child was taken to the operating suite after shock was controlled and 200 c.c. of blood given. The wound of the humerus was cleaned, and immobilization was effected. The patient returned from surgery at 11:30 p.m. with an endotracheal tube in place. Reddish colored froth came from the tracheal tube and respiration became irregular and labored. Death occurred at 12:40 a.m., some six hours and forty minutes after admission. At autopsy the external physical findings were again noted. On section the abdomen was found to be normal except for retroperitoneal hemorrhage in the splenic area. The thoracic cavity showed the left lung to be rotated anteriorly, with its base assuming a superior position and the apex in the inferior position. The cavity contained 500 c.c. of frank blood. Interstitial hemorrhage was present. There was also a small amount of bloody fluid in the right pleural cavity. The heart was normal. Microscopic examination showed interstitial and alveolar hemorrhage. Final Diagnosis: Automobile traumatism; torsion and inversion of the left lung; acute massive pulmonary infarction on the left, with hemothorax; pulmonary atelectasis and congestion on the right with interstitial pulmonary hemorrhage; perisplenic retroperitoneal hemorrhage; compound fracture of the right humerus; fracture of the fourth and fifth left ribs; multiple superficial abrasions, contusions, and lacerations; acute internal hemorrhage of the adrenals.