Research on Comfort and Safety Threshold of Pavement Roughness

Abstract

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.

Effects of the International Roughness Index and Rut Depth on Crash Rates

“…Hu et al developed mathematical relationships between IRI and driving comfort and safety (driving workload) ( 16 , 17 ). The authors developed threshold IRI values on road segments at different risk levels for driving comfort and safety.…”

Passsenger Ride Comfort and International Roughness Index Specifications in the Slovak Republic

“…Such results have not been previously summarized and discussed. Field measurements that reported this relation were rare in the past and most measurements were provided only in recent years [4][5][6][7][8][9][10][11][12][13][14][15]. Comprehensive overview of published relations between the WBV and IRI was provided in [16].…”

“…Limitation of published results [4][5][6][7][8][9][10][11][12][13][14][15] is in limited length and number of processed sections; using only one vehicle speed; using only one test vehicle that does not represent a vehicle fleet; only one (vertical) direction for the WBV evaluation; absence of passenger cars among tested vehicles; long time between the IRI measurement and WBV measurement.…”

International Roughness Index Thresholds Based on Whole-Body Vibration in Passenger Cars

“…Field measurements are still rare and have only been available in recent years ( 4–14 ). An overview of published relationships between WBV and IRI was provided in Múčka ( 15 ).…”

“…The total length of the processed sections ranged from several hundred meters to 58 km ( 4 ). Wheel path(s) used for IRI calculation were mostly not introduced in ( 4–14 ). The elapsed time between road roughness and vibration measurements was not reported.…”