sustainability Article Improvement of Road Safety through Appropriate Cargo Securing Using Outliers Martin Vlkovský 1, * , Jiˇ rí Neubauer 2 , Jiˇ rí Malíšek 1 and Jaroslav Michálek 2   Citation: Vlkovský, M.; Neubauer, J.; Malíšek, J.; Michálek, J. Improvement of Road Safety through Appropriate Cargo Securing Using Outliers. Sustainability 2021, 13, 2688. https:// doi.org/10.3390/su13052688 Academic Editor: Aoife Ahern Received: 30 December 2020 Accepted: 22 February 2021 Published: 2 March 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 Department of Logistics, University of Defence, 662 10 Brno, Czech Republic; jiri.malisek@unob.cz 2 Department of Quantitative Methods, University of Defence, 662 10 Brno, Czech Republic; jiri.neubauer@unob.cz (J.N.); jaroslav.michalek@unob.cz (J.M.) * Correspondence: martin.vlkovsky@unob.cz; Tel.: +420-608-888-646 Abstract: The article focuses on evaluating a transportation experiment that intends to improve road safety by analyzing transport shocks that significantly affect the system of securing the load, vehicle, driver, and other aspects. Within Europe, improper or insufficient securing of loads causes up to 25% of all cargo vehicle accidents. Our transport experiment consists of eight rides of a Tatra truck. The measured values of shocks (acceleration coefficients) are statistically evaluated. Three hypotheses are established for these purposes. First, it is proven that the probability distributions of the shocks values differ statistically significantly among individual rides, namely in their shape and median value. Thus further statistical analyses are performed separately for the individual rides, axes, and the accelerometer locations. These analyses prove significant exceedances of the normatively set limits given by the EN 12195-1:2010 standard, which is potentially risky. Especially for the z axis and y axis, the set 20% limit was exceeded in 75.0% and 56.3% of cases, respectively. In the case of the x axis, the established 20% limit was practically not exceeded at all. The analysis of exceeding the permitted limits (the statistical evaluation of the second and third established hypothesis) is based on boxplots that graphically describe the individual rides, as well as on the found contaminated log-normal distribution of the values of the acceleration coefficients in the individual rides. The last hypothesis regarding exceeding the double value of the permitted limit is rejected. Methods of statistical comparison are used during data analysis. The probability distribution of acceleration coefficients is modeled using a contaminated log-normal distribution. Keywords: road safety; transport experiment; shock; truck accident; cargo securing; boxplot; outliers; contaminated distribution 1. Introduction The cargo vehicle accident rate is a long-term problem in most countries of the Euro- pean Union (EU), and the Czech Republic (CZ) is no exception. The total number of traffic accidents in the CZ increased throughout the last monitored period (2018) by nearly 3% (from 21,263 to 21,889), while over the last five years (2014–2018), this value has more or less stagnated [1]. Globally (year 2018), road traffic accidents are the eighth most common cause of unnatural death among people of all ages, however, it is the number one cause of death for the population from 5 to 29 years old [2]. In the same year, the number of cargo vehicle accidents in the CZ was a total of 11,542, representing nearly 53% of all traffic accidents [3]. According to estimates published by the Directorate-General for Mobility and Transport of the European Commission, based on statistics from most EU states, 25% of cargo vehicle accidents are caused by improper or insufficient securing of the cargo [4]. Recalculated to the CZ in 2018, it is estimated that 2886 traffic accidents had a cause related to securing cargo, representing 13% of the total number of traffic accidents in the CZ in 2018. Although the intentional/careless improper securing of the cargo may be considered a larger problem, it is more of an issue of management and the absence of controls and appropriate sanctions. This article focuses on the segment of cargo vehicle traffic accidents Sustainability 2021, 13, 2688. https://doi.org/10.3390/su13052688 https://www.mdpi.com/journal/sustainability