The influence of footwear sole hardness on slip initiation in young adults

Slips occur when the friction demand of an individual exceeds the friction available from the shoe/floor interface. Shoe sole hardness is one of the factors thought to influence friction demand and available friction. The purpose of this study was to determine the influence of footwear sole hardness on the probability of slip initiation. Forty young adults were randomized into a hard or soft sole group. Slip events during the slippery floor trials were documented using a motion analysis system. The proportion of slip events in the hard sole group was greater than that in the soft sole group. The difference between utilized and available friction accurately predicted 90% of slip outcomes. Our data support the premise that individuals wearing shoes with harder soles are at greater risk for slipping. The results of this study suggest that shoe sole hardness should be considered when designing footwear aimed at decreasing slip risk.     

The transfer and persistence of automotive carpet fibres on shoe soles

The transfer and persistence of automotive carpet fibres to shoe soles was investigated. It was found that fibres were transferred with the normal activity of a car passenger. Carpet type and shoe sole parameters were significant determinants in the number of fibres that transferred. The average number of fibres was between about one and 33 per sole. Fibres that had been transferred after normal activity only persisted for a few minutes after walking. A survey of the shoe soles of people about to leave their car showed that fibres were usually present. The majority of shoe soles surveyed had less than five fibres with the greatest number of fibres found being 14. The likelihood of finding a large number of fibres on such soles is rare. Fibre composition of automotive carpets showed a high degree of variation. Grey was seen to be a common colour irrespective of the colour of the vehicle body.     

Collection of Wet‐Origin Footwear Impressions on Various Surfaces Using an Electrostatic Dust Print Lifter

Electrostatic dust print lift method is known to be able to recover only dry‐origin footwear impression. However, the wet‐origin footwear impression could also be recovered using this method. As the amount of dust accumulated before deposition of the wet‐origin footwear impression increased, the intensity of the footwear impression lifted with this method became stronger. If the footwear impression is not affected by moisture after it is made, the 28‐h old wet‐origin footwear impression could be recovered using this method. The intensity of the lifted footwear impression did not decrease significantly even when the number of sequential steps increased as long as the shoe sole is wet. However, when the moisture on the shoe sole depleted, the intensity of the footwear impression decreased sharply. This method has the advantage of being able to enhance the footwear impression without being affected by the footwear impressions deposited in the past.     

Determining Shoe Length from Partial Shoeprints

The length of a shoe has significant value in reflecting characteristics of the owner, and thereby, it can help in tracking suspects in criminal cases. However, the shoeprints left at a crime scene are often incomplete, resulting in difficulties in assessing shoe length. To find a way to estimate the shoe length from a partial shoeprint, 109 shoes with different sizes and general patterns were collected, and their prints were lifted using magnetic powder. Four feature points were defined on a shoeprint, and the longest distance between the feature points was defined as shoe length. Using linear, quadratic, and cubic regression analyses, a total of 15 equations were obtained between the shoe length and the other distances between the feature points. Out of these, the five most accurate equations were selected as the optimal equation. The verified test, including another 18 pairs of shoes, showed an average error of equations between 0.591 cm and 0.732 cm. The equations were also applied in two practical cases, resulting in good accuracy. The study demonstrates that shoe length could be determined from partial shoeprints through the proven equations.     

A comparison of three shoe sole impression lifting methods at high substrate temperatures

Footwear impressions are a common form of evidence found at crime scenes, and the accurate recovery and recording of such impressions is critical for shoe sole comparison and identification. The lifting of shoe sole impressions from hot surfaces (>30°C/86°F) and in hot environments has received little attention in the literature, particularly in relation to the recovery of class and randomly acquired characteristics (RACs) required for accurate comparisons. This study addressed this knowledge gap by comparing the performance of three common impression lifters (gelatin, adhesive, and vinyl static cling film) at recovering shoe sole impressions in dust from hot flooring substrates. Dry origin dust shoe sole impressions were made on ceramic tile, galvanized metal, and laminated wood flooring using a shoe that possessed two RACs and five class characteristics present on the sole. Substrates were left in direct full sun for five hours during a summer day prior to lifting. Performance was measured by the proportion of RACs and class characteristics visible in each lifted impression. Results demonstrated that the vinyl static cling film tested performed poorly across all substrates, particularly for metal (23.8% marks recovered), including notable shrinkage of the lifted impression. In contrast, adhesive (~96% marks recovered over all substrates), and to a lesser extent gelatin (~85%), lifts were highly successful on hot substrates. These data suggest that adhesive lifts can consistently and accurately recover shoe sole impressions from hot substrates. This study contributes critical information for crime scene examiners to improve and expand evidence recovery in hot environments.     

Less‐Lethal Hybrid Ammunition Wounds: A Forensic Assessment Introducing Bullet‐Skin‐Bone Entity

Abstract: Agencies all around the world now use less‐lethal weapons with homogeneous missiles such as bean bag or rubber bullets. Contusions and sometimes significant morbidity have been reported. This study focuses on wounds caused by hybrid ammunition with the pathologists’ flap‐by‐flap procedure. Twenty‐four postmortem human subjects were used, and lesions caused on frontal, temporal, sternal, and left tibial regions by a 40‐mm hybrid ammunition (33 g weight) were evaluated on various distance range. The 50% risk of fractures occurred at 79.2 m/sec on the forehead, 72.9 m/sec on the temporal, 72.5 m/sec on the sternum, and 76.7 m/sec on the tibia. Skin lesions were not predictors of bone fracture. There was no correlation between soft and bone tissue observed lesions and impact velocity (correlated to distance range). Lesions observed with hybrid ammunition were the result of bullet‐skin‐bone entity as the interaction of the projectile on skin and bone tissues.     

The role of center of mass kinematics in predicting peak utilized coefficient of friction during walking

Slips frequently occur when the friction required between the foot and floor exceeds available surface slip resistance. To date, the ability to identify variables that predict an individual's friction needs during walking, or utilized coefficient of friction (COFU), remains limited. Understanding COFU in the context of pedestrian/walkway accidents is important as individuals who demonstrate higher COFU are at a greater risk of slipping. This study determined if whole body center of mass (CM) kinematics were predictive of peak COFU during walking. Ground reaction forces and kinematic data were recorded simultaneously as subjects walked. Stepwise regression analysis determined that the combination of the subject's CM-to-center-of-pressure angle and CM anterior (i.e., forward) velocity predicted 62% of the variance in peak COFU during weight acceptance (p < 0.001). The identified relationships between CM kinematics and peak COFU provide insight into how gait and individual anthropometric characteristics may increase risk for slip initiation.     

Soft Law in the European Union—The Changing Nature of EU Law

This article is based on the assumption that there is a continuum running from non‐legal positions to legally binding and judicially controlled commitments with, in between these two opposite types of norms, commitments that can be described as soft law. It aims at defining soft law in international relations in order to provide a mapping of EU law on the basis of the soft law/hard law divide. It helps categorise EU competences and public policies, and sees how they fit with the distinction between two kinds of processes: legalisation (transformation of non‐legal norms into soft or hard law) and delegalisation (transformation of hard law norms into soft law and evolution from hard to soft law).     

A Novel Pixel‐Based Method to Estimate the Instantaneous Velocity of a Vehicle from CCTV Images

In traffic forensic identifications, it was usually unfavorable that estimated velocities of questioned vehicles derived from frame‐based methods eventually turned out to be close to but a bit less than speed limits. In this paper, a novel pixel‐based method was presented to estimate vehicles’ relatively instantaneous velocities. First, two adjacent pixels’ actual distance was acquired from the closed‐circuit television (CCTV) images. Then, the instantaneous average velocity within this one frame interval time (FIT) was calculated out. The frame‐based method and its evaluating result were also introduced in this paper. The results showed that the velocity estimated by this new pixel‐based method was higher than which derived from the frame‐based method. Employing this presented novel method in these cases, it could be more accurately identified whether or not the vehicles had exceeded the speed limits, and then the responsibilities could be consequently assigned impartially.     

判别分析法在鞋底磨损特征检验中的应用

目的从统计学角度论证同一人的鞋底磨损特征具有相对稳定性。方法对50名实验对象（同质人群）的穿鞋足迹中的鞋底磨损特征进行量化测量,并对测量结果用判别分析的方法进行处理。结果不同人的鞋底磨损特征具有差异性,并且可用于不同人的鉴别。为利用鞋底磨损特征进行个人识别提供了理论基础。     

A Comparison of Various Fixatives for Casting Footwear Impressions in Sand at Crime Scenes

Footwear examination can provide an important link between the crime scene and the suspect. Casts have been taken from snow, soil, and sand substrates to assist with the examination and to accurately depict the impression. However, there has been some discrepancy on what kind of fixative, if any, should be used with impressions present in sand. This study tested four different fixatives on three sandy substrates. Eight gross characteristics were added to a boot sole, and thirty sand impressions were created in each substrate. Except for one control set that remained untreated, the impressions were treated with a fixative agent before casting. The ninety shoe casts were examined by a qualified footwear examiner and scored based on his ability to see the eight characteristics. The results indicated that pump‐action hairspray was the most successful on play and construction sand, while beach sand impressions without any fixative scored highest.     

Manufacturing processes for athletic shoe outsoles and their significance in the examination of footwear impression evidence

The most common methods of manufacturing athletic shoe outsoles are given and how each method can influence the examination of footwear impression evidence. Several processes for manufacturing athletic shoe outsoles are described. Significant factors of each process that are relevant to the examination of footwear impressions are explained. Some manufacturing processes result in distinguishing random characteristics which can assist in the identification of a shoe sole, even when new. These characteristics, together with the traditionally observed wear patterns and random cuts on the shoe outsoles, enable the examiner a stronger basis for expert opinion.     

Glass particles in footwear of members of the public in south-eastern Australia--a survey

A total of 776 pairs of shoes collected from random members of the public in south-eastern Australia were examined for the presence of glass fragments. From the samples collected a total of 110 fragments were recovered from 57 pairs of shoes (7.3% of the pairs examined). This study shows that the prevalence of glass fragments in footwear is dependent upon the area of the shoe from which the fragments were recovered. A much higher percentage of shoes were found to have fragments embedded in the sole (5.9%) than in the upper area of the shoe (1.9%). These shoes were also more likely to have multiple fragments from multiple sources of glass. Only a very small percentage of shoes contained fragments in both the upper and the sole (0.3%). These findings and their significance for the interpretation of glass evidence involving footwear are discussed in this study.     

Two Simple Formulas for Evaluating the Lower Bound of the Impact Velocity in Vehicle–pedestrian Accidents

Formulas for evaluating the lower bound of the impact velocity are valuable in vehicle–pedestrian accident reconstruction. The theory of classical mechanics and four hypotheses were employed to derive formulas; the research results and simulation/accident tests were employed to validate their feasibility. Then, two simple formulas were developed according to the distance between the rest positions of the vehicle and the pedestrian and the flight‐phase distance. The results showed that the evaluated results by the two proposed formulas are inferior to the existing results. The influence of a roadside step on the impact velocity, which decreased with an increase in the flight‐phase distance and a reduction in the road slope, was evaluated. Based on a real accident, the study concludes that the lower bound can be easily obtained with the proposed formulas, which can be used to determine the evaluated impact velocity during simulations.     

A first time for everything: homicide involving the Brenneke SuperSabot shotgun slug

Sabot shotgun slugs are not a new projectile, but the Brenneke SuperSabot shotgun slug has never been reported in a homicide. We present the case of a 28-year-old man killed with multiple gunshot wounds during an alleged "drive-by" shooting. At autopsy, a 496.2 grain slightly deformed projectile with a base diameter of 5/8' (1.7 cm) was found within the decedent's clothing. Six distinct bullet tracks were identified. An entrance of the anterior right thigh was 3/4 x 5/8' and ovoid, having only passed through the decedent's jeans. This bullet track passed through the soft tissue of the right thigh, exiting out the medial aspect and partially transecting the right greater saphenous vein, re-entering the medial left thigh and re-exiting out the posterior left upper thigh. With the exception of an irregular entrance on the sole of the left foot, which passed through the decedent's shoe, all other entrances were less than 1/2' in greatest dimension. Investigating officers recovered an additional projectile of the same type, which had undergone more extensive deformation after striking and penetrating the tailgate of a truck. Further investigation identified the projectiles as the Brenneke SuperSabot shotgun slugs.     

Physical match: insole and shoe

In this case report, the authors show an interesting case of a physical match between an insole and a suspect shoe that was connected to the crime scene by a blood drop. Several pairs of shoes were seized and inspected. On the insoles of the main suspect's shoes, two different types of prints were seen, one was clear and the other image was faint. A physical match examination was conducted and the authors could place the right insole inside the right shoe. The insole was apparently glued to the shoe by the sweat, heat and dirt inside the shoe, and not by the manufacturer. In this case, the critical questions were how conclusive can the complexity of the random contours be, and whether the physical match between the two objects could pass the "Daubert challenge."     

Shoe print examinations: effects of expectation, complexity and experience

Even though trace evidence is becoming more and more important in legal cases, only little is known about the influence of task and context factors on comparative judgments. In the present study we investigated how expectations and complexity affect shoe print examinations and to what extent differences exist between beginners and experienced examiners. Twelve examiners assessed similarity between a shoe print and a shoe for eight different cases. For half the cases expectation was induced by providing additional incriminating evidence. A complex case meant that the print was relatively noisy, for example because the perpetrator rotated his foot. A simple case meant that the print was clear. The results showed that there was no effect of expectation and no effect of experience. Only complexity affected the examiners' assessments: when the background was noisy, the acquired features received a lower evidential value than when the background was clear. Apparently, examiners compensated for the quality of the print and were more cautious in drawing conclusions when prints were less clear. Even though the results allow for some optimism with regard to the influence of expectations on shoe print examinations, it has to be taken into account that the Dutch procedure is supported by a formal guideline, which may (partly) explain the present findings.     

What shoe was that? The use of computerised image database to assist in identification

The use of a computerised (digital image-based) reference system for the capture, storage and retrieval of shoe soles and uppers has the ability to give quick and reliable information to the investigator in relation to the brand and model of shoe responsible for latent impressions located at crime scenes. The success of the system described is due to the diversity and simplicity of the classification codes, coupled with the ability to search part or all of a shoe sole area. This gives the user greater discriminating power and, with the use of icons and ‘click on’ features, makes the system user friendly when classifying and searching for shoes, thus reducing the possibility of interpretation error.     

Application of Enhanced Point Estimators to a Sample of In Vivo CT‐derived Facial Soft Tissue Thicknesses

Facial approximations based on facial soft tissue depth measurement tables often utilize the arithmetic mean as a central tendency estimator. Stephan et al. (J Forensic Sci 2013;58:1439) suggest that the shorth and 75‐shormax statistics are better suited to describe the central tendency of non‐normal soft tissue depth data, while also accommodating normal distributions. The shorth, 75‐shormax, arithmetic mean, and other central tendency estimators were evaluated using a CT ‐derived facial soft tissue depth dataset. Differences between arithmetic mean and shorth mean for the tissue depths examined ranged from 0 mm to +2.3 mm (average 0.6 mm). Differences between the arithmetic mean plus one standard deviation (to approximate the same data points covered by the 75‐shormax) and 75‐shormax values ranged from ?0.8 mm to +0.7 mm (average 0.2 mm). The results of this research suggest that few practical differences exist across the central tendency point estimators for the evaluated soft tissue depth dataset.