Abstract: An improved tunnel or covered highway structure with means for easy and quick access to the interior. The structure includes a wind tunnel built over a highway and a wind deflector slab provided near the exit end of the tunnel and having an opening for permitting vehicular traffic to pass therethrough. The wind deflector functions to deflect upwardly the air flow generated by the piston action of traffic moving in the tunnel so as to diffuse air pollutants such as carbon monoxide and traffic noise. The wind tunnel includes vent openings and/or side entrances which are normally closed to prevent ventilation of the tunnel therethrough but can selectively be opened to reduce wind pressures generated by piston action of the moving traffic so that the operation of maintenance personnel may not be hampered thereby during repairs.

Abstract: An improved tunnel or covered highway structure with means for easy and quick access to the interior. The structure includes a wind tunnel built over a highway and a wind deflector slab provided near the exit end of the tunnel and having an opening for permitting vehicular traffic to pass therethrough. The wind deflector functions to deflect upwardly the air flow generated by the piston action of traffic moving in the tunnel so as to diffuse air pollutants such as carbon monoxide and traffic noise. The wind tunnel includes vent openings and/or side entrances which are normally closed to prevent ventilation of the tunnel therethrough but can selectively be opened to reduce wind pressures generated by piston action of the moving traffic so that the operation of maintenance personnel may not be hampered thereby during repairs.

Abstract: The present invention is connected with a method for testing a gas diffusion which comprises the steps of rotatably disposing a topography model in the wind passage of a wind tunnel; previously establishing a time distribution of a direction and a velocity of a wind blowing above the topography model; rotating the topography model on the basis of the established time distribution of the blowing wind; discharging a tracer gas from a certain position of the topograph model while changing the wind velocity in the wind tunnel; and testing a diffusion of the tracer gas. Further, the present invention is connected with an apparatus for practicing the above-mentioned method and is concerned with a method for testing a gas diffusion which comprises fixing a topography model in a wind passage of a wind tunnel; and rotating the wind passage about the topography mold on the basis of a time distribution of a wind direction. Furthermore, the present case is concerned with their improvements.