Pavement roughness, which may cause vehicle vibrations and driving instability and even cause loss of control, is the main cause of unsafe and uncomfortable driving. In most countries, the international roughness index (IRI) is used to measure pavement roughness. Driving comfort and safety are currently evaluated with an empirical method of expert scoring, and reliable experimental measurements are not created. Based on previous work, which included evaluation of driving comfort and safety (driving workload) according to physiological and psychological indexes, as well as thresholds of driving comfort and safety, this paper determines the mathematical relationship between IRI and driving workload with experimental data of real vehicles to study the threshold of IRI for driving comfort and safety. Experimental data, including physiological and psychological indexes, driving speed, and IRI, of 12 car drivers and 12 truck drivers driving at a speed of 60 km/h were collected on a road with high alignment elements that had no impact on driving workload in northwest China. The mathematical relationships between IRI and driving workload of car drivers and truck drivers were determined, and thresholds of IRI on road segments at various risk levels for driving comfort and safety were obtained. The results show that standard IRI values for pavement maintenance in China are beyond the comfort and safety thresholds for both car drivers and truck drivers. Methods and conclusions in this paper could provide theoretical and technical support for the improvement of pavement service.
Glare seriously affects the quality of tunnel lighting, and also has a negative impact on drivers’ visual recognition in the tunnel. By introducing the calculation method of glare influence level G and relative threshold increment TI, the article uses DIAlux evo lighting simulation analysis software to simulate and analyze the tunnel lighting glare of different installation spacing and angle combinations under the condition of Symmetrical lighting on both sides in the tunnel. The influence range of glare produced by different installation spacing and angle combinations under symmetrical lighting is obtained. The research results show that: in the symmetrical lighting mode on both sides of the tunnel, when the angle between the driver’s sight line and the incident direction of the tunnel lighting is less than 82.38°, the lamps will produce glare to the driver. When the glare influence level of symmetrical bat-wing tunnel lamp is between 1 and 3 at any installation distance and angle under the symmetrical arrangement of lights on both sides, it is a serious glare effect.
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