# Optimal Longitudinal Texture on Concrete Pavement to Reduce Lateral Vibration of Vehicles
## 3 Driving Simulation Test  
The driving simulation testing equipment has the advantage of enabling testing by combining tire and longitudinal texture as desired. This study used a self-manufactured and validated testing equipment, and the test process is shown in Figure 2. First, the longitudinal texturing specification to be tested was generated on the drum using steel rings. When the texture was generated, the tire to be tested was installed on the wheel. When the texture and tire installation was completed, the tire was moved to the initial position and the desired contact pressure was implemented. In this study, considering the vehicle type and the number of passengers, 2.96 KN was applied for 13-inch tires and 5.34 KN for 18-inch tires. Then, the vibrations and displacements of the tires were measured while the driving speed was maintained at 80 km/h and the tire was moved transversely in small increments. The evaluation method of the testing equipment was as follows: data were measured in each step while moving by 1 mm units in the lateral direction as data was obtained after 500 m pre-driving. The test was completed after measuring a length twice the center-to-center interval of the longitudinal intning or groove. The Min-Max value was determined for the displacement data collected from each step. If the value was larger than the criteria value, it was evaluated that there is a high probability of lateral vibration at that step. Because there was no displacement criteria value for determining lateral vibrations and this was a relative evaluation, this study determined 1 mm as the lateral vibration criteria. For example, because the center-to-center interval of the 3 \(\times\) 3 \(\times\) 19 mm was 19 mm, the test was conducted 38 times by moving the tire along the simulated texture up to 38 mm, which is twice the center-to-center interval. The Min-Max was calculated for each test data sample. In 18 cases where this value was larger than 1 mm, it was determined that the probability of lateral vibration was 18/38 \(\times\) 100 = 46.2%. Tests were performed for 48 cases \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Classification**} & \multicolumn{8}{c}{**Texturing Specifications**} \\ \cline{2-9}  & **3 \(\times\) 3 \(\times\) 19** & **3 \(\times\) 3 \(\times\) 16** & **4 \(\times\) 4 \(\times\) 14** & **2 \(\times\) 3 \(\times\) 19** & **2 \(\times\) 3 \(\times\) 16** & **3 \(\times\) 3 \(\times\) R** & **Average** \\ \hline \multirow{2}{*}{Tire4} & 0.000 & 0.000 & 0.287 & 0.000 & 0.000 & 0.141 & 0.428 \\ \hline \multirow{2}{*}{Tire5} & 0.000 & 0.000 & 0.070 & 0.029 & 0.037 & 0.496 & 0.632 \\ \hline \multirow{2}{*}{Tire6} & 0.000 & 0.000 & 0.043 & 0.000 & 0.000 & 0.000 & 0.043 \\ \hline \multirow{2}{*}{Tire7} & 0.000 & 0.000 & 0.210 & 0.000 & 0.000 & 0.115 & 0.325 \\ \hline \multirow{2}{*}{Tire8} & 0.041 & 0.000 & 0.178 & 0.000 & 0.076 & 0.026 & 0.321 \\ \hline \multirow{2}{*}{Average} & 0.007 & 0.004 & 0.136 & 0.004 & 0.017 & 0.173 & \\ \hline \hline \end{tabular}
\end{table} 
Table 4: _Cont._  
of test parameters in total, including the tire and longitudinal textures examined during the field investigation. Table 6 shows the test results. First of all, the test results for each texture showed very clear patterns. For the timing widths, 3 \(\times\) 3 \(\times\) 19 mm and 2 \(\times\) 3 \(\times\) 19 mm, 3 \(\times\) 3 \(\times\) 16 mm and 2 \(\times\) 3 \(\times\) 16 mm showed similar values. The order of lateral vibration of the center-to-center intervals was 3 \(\times\) 3 \(\times\) 16 mm \(<\) 3 \(\times\) 3 \(\times\) 19 mm \(<\) 3 \(\times\) 3 \(\times\) Random. The driving simulation test results showed that fewer lateral vibrations occurred with smaller center-to-center intervals. When the probability of lateral vibration was examined with respect to tires, small vehicles showed a better result than SUVs. By vehicle type, Tire1 among the small vehicle tires and Tire8 among the SUV tires showed higher possibilities of lateral vibration.