# Evaluation of Adjustment Effects of Highway Guide Signs Based on the TOPSIS Method
## 5 Evaluation Model and Application
### Application of the Evaluation Model
The pairwise comparison matrix constructed for evaluating the effectiveness of highway signage is shown in Table A5 (see Appendix A). In the primary indicators, the normativity and compliance are the fundamental requirements. More importantly, continuity and consistency are pursued only after ensuring normative and compliance standards are met. Therefore, normative and compliance aspects are relatively more significant. After data processing, the weights of each primary indicator are as shown in Table A6 (see Appendix A). The values of CI and CR in the table are both less than 0.1, indicating that the consistency check is satisfied. Determining the weights of secondary indicators: Within the primary indicator of \"Normativity\", the three indicators--location distance sign, exit notification confirmation sign, and guidance sign for roadside facilities--are primarily concerned with whether they are set up correctly. Since these three indicators are of equal importance, their weights relative to the higher-level objective are also equal, as shown in Table A7 (see Appendix A). The weights for the secondary indicators corresponding to the other three primary indicators (Readability, Continuity, and Consistency) are also determined using the AHP. Pairwise comparisons are made regarding the importance of these indicators in relation to their respective primary indicators. The comparison matrices are constructed as shown in Tables A8-A10 (see Appendix A), in accordance with the standards outlined. The summary of the weighted values for all secondary indicators of expressway signage after data processing is shown in Table A11 (see Appendix A). The values of CI and CR in the table are both less than 0.1, indicating that the consistency check is satisfied. Constructing the weighted decision matrix  
Multiply the weights of each indicator by the dimensionless matrix to obtain the weighted decision matrix for the road signs R.  
Determining the optimal and worst solutionsIn this evaluation case, the optimal value for each indicator is 1, which defines the optimal solution as optimal solution \(\text{S}^{+}=\text{M}_{1}\). Similarly, the worst value for each indicator is 0, defining the worst solution as worst solution \(\text{S}^{-}=\text{M}_{2}\). Calculate the distance between solution \(\text{M}_{3}\) and the optimal solution \(\text{S}^{+}\) and the worst solution \(\text{S}^{-}\), respectively. \[\text{Sd}_{3}^{+}=0.0332\ \ \text{Sd}_{3}^{-}=0.3448\]  
The relative closeness \(\text{C}_{3}\) of the solution \(\text{M}_{3}\) to the optimal solution \(\text{S}^{+}\) is  
\[\text{C}_{3}=\frac{0.3448}{0.0332+0.3448}=0.9121\]  
Therefore, the final evaluation indicates that the closeness of this solution to the optimal solution is 0.9121. The effectiveness evaluation of the G2 Expressway's guide signs indicates room for improvement. Six evaluation metrics scored below 0.9: layout compliance rate, visual comfort of spatial arrangement, rational selection rate for hierarchical information, user satisfaction with information prioritization, completeness of advance signage, and appropriateness of route guidance. These findings suggest a need to revise layout standards and enhance advance signage configuration to ensure regulatory compliance. Furthermore, three subjective indicators (i.e., visual comfort, satisfaction with information selection, and appropriateness of route guidance) directly reflect drivers' subjective experiences. This underscores the necessity of optimizing the signage system with a user-centric approach to improve operational usability. Case validation demonstrates that the proposed evaluation method effectively assesses expressway signage performance while providing actionable recommendations for optimization. Such improvements can enhance both traffic safety compliance and user experience outcomes.