## 7 Future Development Trends and Research Prospects
### Theoretical Research Directions  
Specific Theoretical Deficiencies: Current research lacks (1) multi-scale traffic flow theory integrating microscopic lane-changing behavior with macroscopic intersection performance in non-conventional environments, (2) robust control theory for dynamic lane systems under demand uncertainty, (3) network-level impact theory predicting system-wide effects of local non-conventional implementations, and (4) human-machine interaction theory for connected vehicle integration with variable infrastructure. Future theoretical research will focus on constructing a complete theoretical system for non-conventional lane design and control, specifically including the following:  
(1) Spatial-Temporal Relationship Reconstruction Patterns and Adaptability Assessment Theory for Non-conventional Lanes  
Revealing the reconstruction patterns of intersection traffic spatial-temporal relationships after introducing non-conventional lanes is a key scientific issue that needs to be addressed. Future work needs to construct a unified theoretical framework for non-conventional lane design, integrating existing research results [58; 63; 71]. This theoretical system should include a classification system and design criteria for non-conventional lanes, a theoretical foundation and methodology for adaptability assessment, mathematical models and optimization algorithms for dynamic conversion mechanisms, and theoretical frameworks for coordinated control strategies. Particularly important is the establishment of a general theory for spatial-temporal resource allocation of non-conventional lanes, revealing the common patterns and individual characteristics of different types of non-conventional lanes and providing theoretical guidance for the systematic design. (2) Optimal Allocation Theory of Spatial-Temporal Passage Resources Under Mixed Traffic Flow Conditions  
Analyzing the optimal allocation mechanism of spatial-temporal passage resources for intersection non-conventional lanes oriented to mixed traffic flow will become an important research direction [34; 35; 59; 70]. Traditional single-objective optimization can no longer meet the needs of complex traffic systems, requiring the discovery of optimal balance among multiple objectives such as efficiency, safety, environment, and fairness. Future research should develop new multi-objective optimization theories and algorithms, particularly addressing issues such as conflicts between objectives, dynamic adjustment of weights, and robust optimization under uncertainty. Simultaneously, the interpretability of multi-objective optimization results should be studied to help decision-makers understand the trade-offs between different schemes. (3) Coordinated Optimization Theory of Intersection Non-conventional Lanes and Signal Control  
The coordinated optimization theory of non-conventional lanes and signal control needs to be strengthened, requiring research on spatial-temporal coordinated integration of phases, phase sequences, green ratios, and green intervals for motor vehicles, non-motorized vehicles, and pedestrian traffic, as well as optimal signal timing methods for phase difference coordination with related intersections. Mechanism research at the microscopic level is the foundation for macroscopic optimization [12; 13; 23; 50]. Future research needs to further explore the evolution patterns of mixed traffic flow in non-conventional lane environments, behavioral characteristics and adaptation processes of different types of drivers, interaction mechanisms under human-machine mixed driving conditions, and self-organizing characteristics of traffic flow under abnormal events. Especially in a connected and automated vehicle environment, traditional traffic flow theory needs to be modified and extended to adapt to new technological conditions. Discussion of theoretical research directions indicates an urgent need to establish a systematic theoretical system in the field of non-conventional lanes to guide engineering practice and technological innovation.