# Accelerometer-Based Pavement Classification for Vehicle Dynamics Analysis Using Neural Networks
## 3 Results
Following 0.5 s of acceleration, the jumps diminish, and by 1 s, the graph approaches a linear trajectory, suggesting that the vehicle has either decelerated or passed the largest obstacles and returned to a smoother surface. The hump surface, while exhibiting less irregularities than the grate surface, substantially impacts the vehicle, particularly when the wheels strike singular huge protrusions. These leaps may induce abrupt variations in acceleration, as seen in the graph, and exert significant stress on the vehicle's suspension and unsprung mass. The accelerometer captures significant variations in acceleration whenever the wheels traverse a bump, enabling it to derive data specific to this surface type. The primary issue presented by potholes (Figure 4) is the abrupt displacement of the unsprung mass (wheels and suspension) during the entry and escape of the wheels from the pothole. Figure 4 demonstrates the impact of abrupt changes on vehicle dynamics. Beginning at 0 s, Figure 4 illustrates a rather smooth trajectory of vertical acceleration, with minor oscillations either attributable to typical surface imperfections or the transitional phase before the car encounters the potholes. Beginning at around 0.3 s, the acceleration exhibits notable fluctuations, suggesting that the wheels are beginning to meet minor irregularities in the road surface, such as tiny bumps or minor potholes; however, these variations are not yet as strong as those shown later in Figure 3.  
A very strong acceleration peak, surpassing +200 m/s\({}^{2}\), is found between 0.9 and 1.1 s. This is a certain indication that the vehicle's wheels have encountered a substantial pothole. Concurrently, just after this apex, the acceleration declines to around \(-\)150 m/s\({}^{2}\), indicating that the car exited the pit shortly thereafter. Sudden increases in vertical acceleration are  
Figure 3: The acceleration peaks observed on a thump surface with large irregularities: (**a**) the acceleration graph; (**b**) an example of the surface. characteristic of traversing deep potholes, as the wheels quickly plunge into the depression and then emerge, resulting in significant effects on the vehicle. The significant fluctuation in acceleration during the one-second interval signifies the most substantial external influence on the sprung mass during the experiment. This impacts both the vehicle's suspension system and the quality and safety of driving. This coating may inflict significant harm on the vehicle's wheels and suspension, particularly at elevated speeds. Subsequent to this disturbance, the acceleration normalizes, and within 1.2 s, the trajectory approaches linearity, indicating that the vehicle now traverses calmer terrain or minor irregularities after a significant pothole. Figure 4 clearly illustrates that the effect of potholes on a vehicle is notably severe, since deep potholes induce significant vertical accelerations that fluctuate rapidly between high and low values. This substantially impacts the vehicle's stability, and potholes might be among the most hazardous surfaces, concerning both possible damage to the automobile and the driver's comfort. Figure 5 illustrates the acceleration of a vertically suspended mass as it traverses a surface composed of concrete cubes. This pavement is often used in urban settings, particularly in historic sections of European towns where streets or pavements are covered with concrete tiles or cubes. This coating has uniform intervals between the cubes, resulting in constant although comparatively milder vibrations than those produced by coarser coatings like grates or pits. Figure 5 clearly illustrates variations in acceleration at a rather regular frequency, indicative of the continuous interaction between the wheels and the interstices of the concrete cubes. Between 0 and 0.25 s, the graph illustrates an early, rather smooth motion with acceleration values marginally above \(\pm\)50 m/s\({}^{2}\).