Question

hegg Study TEXTBOOK SOLUTIONS EXPERT ORA PRACTICE NEW affic Engineering (4th Edition) Bookmark Chapter 15, Problem 3P Show all steps ON Problem Consider the on-ramp shown in Figure Figure: Segment for Problem Freeway 4,200 veh/h 8 % trucks Level terrairn FFS- 65 mil/h PHF 0.92 Ramp 700 veh/h 5% trucks Level terrain RFFS 40 m/h PHF-0.92 (a) At what LOS would the merge area be expected to operate? (b) A new development nearby opens and increases the on-ramp volume to 1,000 veh/h. How does this affect the LOS?

Answer 1

Step - I Flow rate v_p = V/ PHF times N times F_NV times F_p heavy vehicle adjustment factor (F_HV) = 1/ 1 + p_T (E_T - 1) rightrarow for trucks = 1/ 1 + 0.05 (1.5 - 1) = 0.975 Driver population factor (F_P) = 1 v_p = 700/0.92 times 1 times 0.975 times 1 [because N = 1 for merge area road] = 780 veh/hr/lane step 2: free flow speed of ramp (RFFS) = 40 mid/hr step 3: density D = V_p/RFFS = 780 /40 = 19.5 veh/hr/lane Step 4 level of service for RFFS = 40 mph & density = 19.5 veh/hr/lane therefore level of service = B \r\n Step_I flow rate for increases in ramp volume V_p = V/P_HF times N timers F_HV times F_p = 1000/0.92 times 1 times 0.975 times 1 v_p = 1115 veh/hr/lane step 2 free flow speed (or) ramp (RFFS) = 40 mph