Teknik Dergi, 2022 12329-12334, Paper 684, Technical Note Sliding and Rollover on Highways - Subtleties to Note * Banihan GÜNAY 1 ABSTRACT While the horizontal curves have a duty to protect all types of road vehicles against sliding as well as rollover, the fact that different vehicle types lose their stability for competing criteria makes this task difficult and vital. In relation to the sliding and rollover of a vehicle undergoing centripetal acceleration, this technical note discusses a number of unclear interpretations of some statements seen in reference books and how their better understanding should be. This note has been prepared to observe such benefits as accident investigations, determination of pavement rehabilitation frequencies, and most importantly, ensuring the correct student learning. Keywords: Static stability factor, rollover threshold, tripped rollover. 1. INTRODUCTION Whereas sliding is adequately discussed in many highway engineering books [1-18], it is prominent that the topic of rollover (also known as overturning) has found no mention in these sources. Yet, rollover type accidents are the second most fatal accidents after head-on collisions [19]. It has been proven that a loaded truck rolls over at a speed of 25 km/h on a 20 m radius curve [20] and at only 5 km/h above the design speed on a minimum radius curve [21]. More interestingly, even if the trailer of a truck begins to roll over, the driver in the front cabin, which has a lower centre of gravity, may not be able to feel the danger [22]. Certain statements in a limited number of books containing discussions on rollover however, are sometimes misinterpreted (Section 2). These details may be overlooked in newly prepared textbooks or lecture notes and erroneous interpretations may have been repeated to date. Before commencing the discussion of the topic, the dynamics of sliding and rollover with point mass [23] simplification † will be summarised here. On a level surface, the forces acting on a vehicle (Figure 1) moving in a circular motion in the plan view are its weight (mg), the centrifugal reaction (mv 2 /R), and the frictional force (µmg). In order for this vehicle (with rigid wheels and body) not to slide laterally, the Note: - This paper has been received on July 9, 2020 and accepted for publication by the Editorial Board on March 1, 2021. - Discussions on this paper will be accepted by September 30, 2022.  https://doi.org/10.18400/tekderg.766631 1 Metropolitan University of Tirana (UMT), Department. of Civil Engineering, Tirana, Albania bgunay@umt.edu.al - https://orcid.org/0000-0002-4640-417X † With increasing number of wheels of the vehicle, the point mass simplification becomes rather cumbersome.