Dataset for Lane-Dependent Speed Asymmetry Across Expressway Tunnel Portals: A Field-Based Transition–Recovery Analysis in Mountainous Terrain

<p dir="ltr">This dataset supports the study entitled “Lane-Dependent Speed Asymmetry Across Expressway Tunnel Portals: A Field-Based Transition–Recovery Analysis in Mountainous Terrain.” The dataset contains derived field-based operating-speed observations collected at the Menora–Meru Tunnel on the North–South Expressway, Malaysia. It comprises 80 lane- and zone-specific 85th-percentile speed (V85) observations across ten five-minute observation intervals and four spatial locations: 50 m before the tunnel entrance, at the tunnel entrance, at the tunnel exit, and 50 m after the tunnel exit.</p><p dir="ltr">The dataset was prepared to support the analysis of lane-dependent operating-speed variation and transition–recovery behaviour at expressway tunnel portals.

Variables include observation interval, tunnel transition zone, location, traffic lane, and V85 speed in km/h. A data dictionary and supporting metadata are included in the accompanying Excel workbook.</p><p dir="ltr">Raw individual-vehicle LIDAR records are not reconstructed in this public dataset. Traffic-volume data supplied by PLUS Malaysia Berhad are also not included because they may be subject to third-party data-sharing restrictions.