## 3 Results and Discussions
### Acceleration/Deceleration  
The results of the within-subjects repeated measures ANOVA, with Greenhouse-Geisser correction for acceleration/deceleration (acc/dec), are presented in Table 4. It indicates that both curve radius (\(F\)(1.00, 46.00) = 6.73, \(p\) = 0.013, \(\eta^{2}p\) = 0.02) and measuring point (\(F\)(2.69, 123.57) = 71.27, \(p\) < 0.001, \(\eta^{2}p\) = 0.61) significantly impacted acceleration and deceleration. This showed that the measuring points and the curve radii significantly affected the differences in acceleration. However, the curve direction and condition factors were insignificant, suggesting that the differences in ACC and DCC were not noticeably different across different conditions and curve directions. Moreover, the two-way interaction effects of curve direction \(\times\) condition (\(F\)(3.86, 177.37) = 3.29, \(p\) = 0.014, \(\eta^{2}p\) = 0.07) are significant. This means that the effect of curve direction on acceleration/deceleration depends on the road condition. Depending on the visual road treatments, drivers may respond differently to the left vs. right curves. In addition, the two-way interaction effect of curve radius \(\times\) measuring point (\(F\)(2.58, 118.61) = 75.28, \(p\) < 0.001, \(\eta^{2}p\) = 0.62) is highly significant. This means that the impact of the curve's radius on acceleration/deceleration varies significantly depending on the location within the curve. \begin{table}
\begin{tabular}{c c c c c} \hline
**Effect** & _df_ & \(F\) & \(p\) & \(\eta^{2}_{p}\) \\ \hline Curve direction & (1.00, 46.00) & 0.975 & 0.328 & 0.021 \\ Curve radius & (1.00, 46.00) & 6.730 & **0.013** * & 0.128 \\ Condition & (3.72, 170.88) & 2.254 & 0.070 & 0.047 \\ Measuring points & (2.69, 123.57) & 71.267 & **<0.001** & 0.608 \\ Curve direction \(\times\) Curve radius & (1.00, 46.00) & 1.004 & 0.322 & 0.021 \\ Curve direction \(\times\) Condition & (3.86, 177.37) & 3.290 & **0.014** & 0.067 \\ Curve radius \(\times\) Condition & (3.55, 163.46) & 0.361 & 0.814 & 0.008 \\ Curve direction \(\times\) Curve radius \(\times\) Condition & (3.33, 153.30) & 1.044 & 0.379 & 0.022 \\ Curve direction \(\times\) Measuring points & (3.39, 155.99) & 1.350 & 0.258 & 0.029 \\ Curve radius \(\times\) Measuring points & (2.58, 118.61) & 75.275 & **<0.001** & 0.621 \\ Curve direction \(\times\) Curve radius \(\times\) Measuring points & (3.30, 151.77) & 1.167 & 0.326 & 0.025 \\ Condition \(\times\) Measuring points & (9.36, 430.50) & 3.035 & **0.001** & 0.062 \\ Curve direction \(\times\) Condition \(\times\) Measuring points & (10.49, 482.60) & 1.828 & **0.050** & 0.038 \\ Curve radius \(\times\) Condition \(\times\) Measuring points & (9.51, 437.23) & 0.836 & 0.589 & 0.018 \\ \hline \end{tabular}  
* Bolded values are statistically significant at the \(p\) < 0.05 level.  
\end{table} 
Table 4: Analysis of acc/dec: within-subjects repeated measures ANOVA with Greenhouse-Geisser correction. Figure 7: Average speed across conditions and measuring points. Drivers adjust their speed differently based on how sharp the curve is. Another significant two-way interaction is condition \(\times\) measuring point (\(F\)(9.36, 430.50) = 3.04, \(p\) = 0.001, \(\eta^{2}_{p}\) = 0.06), meaning that road marking conditions affect acceleration/deceleration patterns differently at various measuring points. Some markings may encourage earlier or later deceleration in the curve. The three-way interaction effect for the factor curve direction \(\times\) curve radius \(\times\) measuring point (\(F\)(10.49, 482.60) = 1.83, \(p\) = 0.050, \(\eta^{2}_{p}\) = 0.04) was also marginally significant, suggesting that the combined effect of curve direction and road markings might vary across measuring points, but the evidence is weak. The descriptive statistics and pairwise comparisons of acc/dcc for the road marking conditions, adjusted using the Bonferroni correction, are presented in Table 5. The acceleration in the RWE condition was the highest compared to the other conditions.