Traffic Volume Study and Intersection Capacity Analysis of Selected Junctions on NH 169A, Udupi–Shivamogga Corridor

Rapid growth in vehicle ownership and tourist movement has made National Highway 169A, which links Udupi to Shivamogga through the coastal and Malenadu regions of Karnataka, increasingly congested and accident-prone. This study investigates two unsignalized T-intersections on this corridor, Athrady and Hiriyadka, with the aim of quantifying prevailing traffic conditions and recommending engineering measures to improve safety and efficiency. Classified traffic-volume counts were carried out manually over two consecutive days at each intersection, covering the morning (08:00-10:00) and evening (16:00-18:00) peak windows, and vehicle counts were converted to Passenger Car Units using Indian Roads Congress conversion factors. Speed and delay characteristics were measured on three connecting stretches using the floating-car method, and a road-inventory survey covering twenty-eight geometric, signage, marking and safety parameters was conducted along the six-kilometre study stretch. Intersection capacity was estimated using the Indian Roads Congress weaving-section formula for rotary design, and signal timings were computed by Webster's method. Results show a critical peak-hour flow of 1,498 PCU/h at Athrady (09:00-10:00) and 868 PCU/h at Hiriyadka (17:00-18:00), with two-wheelers and passenger cars together contributing more than three-quarters of the flow at both locations. Running speeds along the corridor ranged between about 44 and 81 km/h. The inventory survey found an absence of street lighting, crash barriers, guideposts and marked pedestrian crossings along most of the stretch. Weaving-section analysis gave rotary capacities of 2,056 veh/h at Athrady and 2,092 veh/h at Hiriyadka, while Webster's method yielded optimum cycle times of 52 seconds at Athrady and 120 seconds at Hiriyadka. The study concludes that signalisation is practicable at Athrady, whereas the excessive cycle length at Hiriyadka favours a channelised roundabout with improved lighting and signage instead.