## 4 Discussion  
With the increasing cases of traffic violations and accidents in Metro Manila, the current study examined the comprehension of Filipino drivers and nondrivers of the 73 existing traffic signs for their matching accuracy, matching time, and cognitive design features. Since several studies have already investigated the effects of age, gender and educational attainment on the comprehension level of traffic signs, these were not analyzed in the current study, as they all fall under the non-design category of comprehensibility. While drivers' characteristics may have a significant effect on comprehensibility, this study focused on the design factors, such as the type and display conditions, which are more flexible to modifications than the characteristics of drivers. The results of the study showed that signs displayed in text may have higher matching accuracy, but not necessarily with faster matching times. For example, \"Left lane must turn left\" obtained a 100 percent matching accuracy, but it was the \"Bike Lane\" sign, which was displayed in symbol form, which was matched the fastest at 2.71 s. Similarly, \"B\" the minimum speed limit of 40 sign obtained a 100 percent matching accuracy, but it also registered one of the slowest matching times at 10.14 s. While some traffic signs were fully comprehended, the effect of late reaction could affect the driver's preparedness and subsequent responsiveness to events [36]. Thus, traffic sign effectiveness is not only attained through comprehension matching accuracy, but also through comprehension matching time. Traffic signs are designed to prevent accidents and help road users adapt to the environment easily. However, almost thirty-seven percent of the 73 traffic signs failed to meet the 67% comprehension test passing rate set by ISO 3864-1:2011 [25]. Between the two types of traffic signs, warning signs were more often miscomprehended, especially those presented in symbols. Symbolic signs are often misunderstood by drivers, even those that have already been standardized and used throughout the world [14]. For example, [PERSON] et al. [37] found that low comprehension levels existed for several traffic symbols when evaluated by more than 3000 drivers in Texas. The use of symbols is sometimes preferred because it facilitates large amounts of information (relative to text occupying similar surface area) and avoids varying language and reading abilities among users. However, most of these symbols are poorly designed and difficult to understand [16; 28]. Lack  
\begin{table}
\begin{tabular}{l c c c c c} \hline \hline Cognitive & \multicolumn{3}{c}{Highest Rating} & \multicolumn{3}{c}{Lowest Rating} \\ \cline{2-6} Design Features & Regulatory & Warning & Regulatory & Warning \\ \hline \multirow{3}{*}{Concreteness} & \multirow{3}{*}{
\begin{tabular}{c}  
of understanding may reduce its intended purpose and may lead to violations and road accidents, including errors in making predictions about other road users' actions [38; 39]. To increase the comprehension of traffic signs, there is a need to redesign signs that failed the 67% comprehension standard, which were mostly symbolic signs. The proposed designs should be direct, simple, and closely related to the meaning by considering user perceptions [40; 41]. With user participation in the design process, signs are more likely to be interpreted correctly by the intended meaning because they were directly mapped from the mental models of users [42; 43]. However, redesigning the traffic sign based on the user's perception is not enough because everyone has a different perception. [PERSON] et al. [19] incorporated ergonomic principles in redesigning the 21 poorly designed road warning signs in the Philippines. The redesigned alternatives led to substantial improvements in the comprehension level of drivers. Therefore, the 27 traffic signs that failed the 67% comprehension standard should also be redesigned, incorporating cognitive design features to increase comprehension scores.