## 6 Discussion and Conclusions
### Policy and Research Implications  
Policy implications of this review are particularly salient. First, decision makers should prioritize flexible PTI designs capable of accommodating different demand scenarios and user groups. This includes adopting universal design standards, enforcing crowd behavior protocols, and integrating crowd management into contract performance indicators for transport operators. Second, regulations should mandate that infrastructure projects systematically incorporate evidence from laboratory-based pedestrian studies, ensuring that public funds are directed toward solutions with proven behavioral impact. Finally, policy should recognize that PST variability is both a service quality and equity issue. Delays disproportionately affect PRMs and exacerbate existing accessibility gaps; thus, improving crowd flow is not merely a matter of efficiency but of social inclusion [48; 71].  
The methodological convergence of behavioral observation, simulation modeling, and experimental testing constitutes a promising path forward for PTI optimization. However, as identified in this review, a gap persists between the academic knowledge base and real-world application. Bridging this gap requires greater institutional coordination, investment in professional training, and the development of open-access tools that enable transport agencies to implement findings in a scalable way. Stakeholders in design, operation, and policy must work in concert to ensure that the lessons derived from research are transformed into daily practice. Without such integration, the risks of inefficiency, congestion, and exclusion at the PTI will remain unresolved despite growing scholarly consensus on effective measures.  
In conclusion, future research should focus on validating proposed crowd management interventions under live operating conditions and over extended periods. Longitudinal studies examining behavioral adaptation, particularly under changing urban mobility patterns, will enhance the resilience and adaptability of public transport systems. Moreover, interdisciplinary collaborations--bringing together engineers, designers, psychologists, and urban planners--will be essential to advance holistic PTI solutions. By grounding  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Variable** & **Value** \\ \hline Door width & In the range between 1.65 m and 1.85 m; the capacity of the doors will increase if a new line of flow is generated between passengers boarding or alighting the train. \\ \hline Vertical handrail & Located not in the middle of the hall of the carriage but displaced to the start or end of the aisle; if the vertical handrail is in the middle of the hall, then passengers can block the train doors. \\ \hline Seat layout & Parallel to the movement of the train brings more space in the aisle; in addition, seats should have handrails, especially for PRMs. \\ \hline Markings on the floor & Waiting areas should be implemented to let alight first and then boarding. Signage and colors can be used to differentiate the boarding and alighting areas. \\ \hline PEDs & The use of PEDs can change the behavior of passengers on the platform as they wait beside the doors rather than in front of them. In addition, PEDs avoid passengers from falling onto the tracks. \\ \hline Space for PRMs & Waiting areas for PRMs should allow them to maneuver in a 1.5 m diameter circumference. \\ \hline Space for bikes & Waiting areas inside the train should be used for passengers with bikes (e.g., 2 or 3 spaces for bikes per carriage). In addition, it is desirable to define specific cars for placing bikes. \\ \hline \hline \end{tabular}
\end{table}
Table 3: _Cont._planning and design decisions in empirical evidence and human-centered principles, cities can create safer, more inclusive, and efficient transit environments for all.