Driver Workload Evaluation on the Basis of Design Criteria in Rural Road of Kaski, Nepal

Er. Prakash Baral

Vehicle Stability, Driver workload, Operating speed, Vehicle stability

Road fatalities are severe these days not only in developing countries but also in developed countries too. Various criteria (methods) are explored to minimize fatalities like continuous speed profile, alignment index, and vehicle stability and driver workload method. Though most of the explorations are based on continuous speed profile, this paper focus on estimation of threshold value of driver workload (V_d) based on design criteria and crash rate (CR) for a rural road section. Three test curves were observed on Methlang-Gyarjati road section and analyzed based on variation in speed, vehicle stability and driver workload itself.This paper focus on utilization of different design criteria in the estimation of driver workload in rural road of Kaski. Visual demand (V_d) is determined from pre-determined model (V_d =0.173+43/R) where road geometric feature radius is taken into consideration. The moderate value of workload 1.2 was obtained from test curve section 1 which is between 1.9(maximum) and 0.7(minimum).From criteria 1, test curve holds good during design evaluation with a value of 9.59 which is less than 10Km/hr, but vehicle stability method (Δf_R) holds poor for all the test curve section under observation. Driver workload is minimum of all and crash rate is also minimum with a value of 5.83 for test curve section 1.So, overall from the above evaluation improvement on curve section 2 and 3 are required from driver workload(visual demand) point of view in comparison to 1 which holds good criteria on the basis of variation in speed. Therefore, from safety criteria aspect as well as design consistency the threshold value of driver workload (visual demand) is 1.2 which is good to meet the driver expectations in rural road of Kaski district.