Slip and fall cases: Using the BOT 3000E

Some of the most frequent cases for forensic or human factor experts are slip and falls. Various tribometer devices exist within the forensic field including the English XL, the German ramp, SlipAlert, Tracscan, TORTUS, American Slipmeter (ASM), GS-1 and the BOT 3000E, yet not all tools provide the best methodology for accurate measurements. For example, it is important to differentiate that the English XL measures only slip index which is not correlated to coefficient of friction. Tribometers testing for coefficient of friction (COF) would help in determining the probability of whether or not a level surface could contribute to someone slipping or falling.

Dynamic COF (DCOF) is a measurement for how much friction there is on floors when walked upon, that is when two surfaces are in motion with each other, creating friction; static COF (SCOF) is the measurement of two surface when they are in a resting position with respect to each other. 

Dynamic friction is used to assess when the pedestrian is walking on a sidewalk. Since most slipping injuries occur while an individual is moving (i.e., in a “dynamic” state) DCOF is the appropriate test method to assess pedestrian safety. Understanding the difference between SCOF and DCOF is necessary for analyzing a slip and fall case, and subsequently, using the appropriate tribometer. As seen in Figure 1, only DCOF has standards pertinent to it.

Since the BOT 3000E can measure both DCOF and SCOF in wet and dry conditions, it is highly adaptable to a variety of cases or incidents. It is also a popular choice for measuring COF for determining slip resistance, or “slipperiness,” of a surface because it is best used to compare the slipperiness of different surfaces. Slipperiness is affected by multiple extraneous factors, such as, but not limited to the material of the surface being tested, dirt, water, soap, grease, snow, gravel, etc. 

This device is considered a user-friendly tribometer that can be used for walkway surfaces in laboratory and real-world environments. First-hand experience at Explico has determined the BOT to be one of the most robust tribometers for documentation of COF. Our team of trained Human Factor and Biomechanics experts have trained and used other devices, yet the BOT continues to stand out due to its uniformity, repeatability of results, and limiting user input and subjectivity.

Features of BOT that assist with admissibility

Various feature of the BOT assist with admissibility of its results in court:

• A validation procedure and tools are included with the tribometer, which gives an assurance of calibration.

• Due to the lack of human input needed, it is considered precise and reliable in measuring COF.‍

• An operator can’t unknowingly manipulate the test results, which results in multiple and repeatable measurements without much interaction.‍

• Generally accepted by the standards. Validated and certified by an independent laboratory, so that it meets ASTM 2508 – a standard for standard walkway tribometers. 

• The only device qualified for using ANSI A326.3. the ANSI standard is the only standard for measuring DCOF and represents the sound scientific methodology published in the current research required to meet Daubert rulings.‍

• Capable of taking pictures during testing (Figure 3), which can be reproduced in report along with other COF raw data collected incapable of being altered.

Limitations

• The BOT 3000E, by itself, will not address all issues makes associated with footwear, human ambulation, or perception and expectation. The environment itself, biomechanics of the individual’s body, and their experience with their environment should always be considered in order to conduct a holistic analysis of a slip and fall situation, which requires specialized expertise, knowledge, or training.

How Explico Can Help

Explico can provide the expertise to evaluate the contributions of system attributes that cannot be measured by any tribometer on its own. The scientists and technicians at Explico know how to properly utilize the BOT 3000E for floor COF testing and can use the data from the BOT and pair it with other analysis, such as: motion capture data, footwear information, scientific literature, and facts of the case in order to come to a scientifically accurate conclusion of what occurred during an incident. Animations of a slip and fall/trip and fall can also be provided when needed, as seen below.
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