The Adverse Effects of Depression-Type Distress on Driving in Asphalt Pavements

Depressions are a type of distress that cause whole-body vibration (WBV) on people traveling in vehicles, adversely affecting traffic safety, especially at high driving speeds. The study investigated the WBV levels of people traveling in the vehicle during the passage of passenger cars over depressions at the depths defined in the standard. In this context, vibration measurements were made in the vehicle at various driving speeds on some road sections with a known vertical profile with a passenger car. The road sections have been selected with a speed control hump in the middle of the section to consider extreme changes while riding. Vehicle responses were digitized by calibrating a half-vehicle dynamic model with the help of profile data of known geometry and vibration data. WBV values occurring in the seats of vehicles caused by depression type distress in nine different sizes, three different depths defined in low (L), medium (M), and high (H) severity levels and three different widths at each depth, were dynamically simulated. The evaluations were repeated for road profiles expressing A and B classes according to ISO 8608. In the simulation, vibration values were produced by changing ten units to see the change in vibration parameters in the range of vehicle speeds between 10 and $100\mathrm{km}/\mathrm{h}$, and the effects of driving speed on WBV were also taken into account. Vibration data were analyzed using vertical weighted root-mean-square acceleration (${\mathrm{a}}_{\mathrm{w}}$), vibration dose value (VDV), and equivalent static compressive stress (${\mathrm{S}}_{\mathrm{e}}$) parameters defined in the ISO 2631 standard. The analysis shows that with the increase in driving speed, the discomfort increased by 16% in depressions of 0.5 m width, 26% in depressions of 1 m width, and 79% in depressions of 3 m width.