Japan has many active volcanoes, and a large eruption can cause ash fall over a wide area. The accumulation of volcanic ash on paved roads affects the driving of vehicles. Therefore, we collected data by driving over volcanic ash accumulated on paved surface with a vehicle equipped with devices that can measure the force applied to the running tires. Vehicle driving tests were conducted at constant speed, rapid acceleration, and rapid deceleration. Data were collected on flat straight roads as well as on roads with grades and curves. In addition to longitudinal, lateral, and vertical tire forces, camber angle, rotation speed, and ground speed were measured. This paper discusses the effects of volcanic ash covering paved roads on driving by processing the tire data obtained. The relationship between the sideslip angle and side force can be obtained by processing turning driving data, and these effects were modeled using a neural network and Gaussian process that can consider multiple variables such as tire sideslip angle, camber angle, and vertical force. (c) 2024 ISTVS. Published by Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.