Tieverkkoanalyysi

Tieverkkoanalyysi, or road network analysis, is the systematic study of road transport networks to understand performance, capacity, and accessibility and to support planning and operation decisions. In practice, it treats the road network as a graph, where intersections are nodes and road segments are edges with attributes such as length, number of lanes, capacity, free-flow speed, and permitted movements. Demand is typically described by origin–destination matrices, which record the number of trips between zones or areas.

Analytical approaches include static and dynamic traffic assignment, where travelers are assumed to choose routes based on costs like travel time; Wardrop's equilibrium principles are applied in static models. Macroscopic models describe aggregate flow and density, while microscopic simulations model individual vehicle interactions. Data-driven methods use GPS traces, traffic counts, probe data, and mobile sensor data to calibrate and validate models.

Applications cover long-range planning, capacity expansion, operation and incident management, and performance assessment. Outputs include travel times, delays, speeds, reliability measures, level of service, and network accessibility metrics. Tools range from GIS-based network analysis to specialized software such as VISUM, TransCAD, AIMSUN, SUMO, and MATSim, often integrated with land-use models.

Validation requires calibration against observed data and, where possible, cross-validation. Tieverkkoanalyysi faces challenges such as data quality, dynamic variability, and uncertainty, as well as integration with land-use change and environmental considerations. The analyses inform decisions on road design, maintenance prioritization, and policy measures aimed at reducing congestion and improving mobility.