Tiêu đề Day 49 - Transportation Engineering (1).pdf ✅

DAY 49: TRANSPORTATION ENGINEERING SIGHT DISTANCE "Think like a signal light—stay alert, plan your move, and always go for green." 2. Stopping Sight Distance The stopping sight distance is the length required for a driver to stop the vehicle after seeing an object in the vehicle’s path without hitting the object. This distance is the sum of the distance traveled during perception-reaction time (lag distance) and while braking (braking distance). During the perception-reaction time, which DPWH provides to be 2.5 s, the vehicle undergoes a uniform motion (no acceleration). d1 = vt When the driver starts to brake, the vehicle undergoes a uniformly accelerated motion with deceleration −g(f ± G). The factor (f ± G) incorporates the effects of friction and gravity. To fully stop, vf 2 − vo 2 = 2ad 02 = v2 = −2g f + ±G d2 d2 = v2 2g f ± G where: v = velocity of vehicle g = acceleration due to gravity f = coefficient of friction G = grade of roadway in decimal, positive if upward and negative if downward