Explanation The level of service is LOS C . Given: The free flow speed is 65 mi / h . The analysis directional flow is 182 veh / h . The opposite directional flow is 78 veh / h . The peak hour factor is 0.90 . Formula Used: Write the expression for the analysis flow rate. v p = V P H F × f G × f HV …… (I) Here, v p is the flow rate, V is the hourly volume, P H F is the peak hour factor, N is the number of lanes and f HV is the heavy vehicle adjustment factor. Write the expression for the heavy vehicle adjustment factor. f HV = 1 1 + P T ( E T − 1 ) + P R ( E R − 1 ) …… (II) Here, P T is the proportion of the heavy vehicles and E T is the passenger car equivalent for heavy vehicles. Write the expression for average travel speed. A T S d = F F S − 0.00776 ( v d + v o ) − f n p …… (III) Here, A T S d is the average travel speed. Write the expression for base percent spent time. B P T S F d = 100 [ 1 − e a v d b ] …… (IV) Here, B P T S F d is the base percent spent time and a , b are constants. Write the expression for percent spent time. P T S F d = B P T S F d + f np ( v d v d + v o ) …… (V) Here, P T S F d is the percent spent time. Calculation: Refer Table 6.16 “Passenger car equivalent for heavy vehicles for average travel speed” of the book “Principles of Highway Engineering and traffic, 6 th Edition.” The E T for truckfor rolling terrain is 1.9 . Substitute 1.9 for E T , 0 for P R , 1 for E R and 0.15 for P T in equation (II). f HV = 1 1 + 0.15 ( 1.9 − 1 ) + 0 ( 1 − 1 ) = 1 1 + 0.135 = 1 1.135 = 0.88 Refer Table 6.15 “Grade adjustment factor for average travel speed” of the book “Principles of Highway Engineering and traffic, 6 th Edition.” The f G for truck for level terrain is 1 . Substitute 0.9 for P H F , 1 for f G , 0.93 for f HV and 182 for V in equation (I). v d = 182 0.9 × 1 × 0.93 = 182 0.837 ≈ 217 pc / h Substitute 0.9 for P H F , 1 for f G , 0

The level of service of highway.

EBK PRINCIPLES OF HIGHWAY ENGINEERING A

6th Edition

ISBN: 9781119299332

Author: WASHBURN

Publisher: JOHN WILEY+SONS,INC.-CONSIGNMENT

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Question

Chapter 6, Problem 30P

To determine