Question

Problem 1

On freeway 3 lanes each direction serving traffic to and from coastal beach resorts, determine the level of service when the following parameters are given:

PHF = 0.90

Lane width = 11 ft

Rolling terrain

Average space of interchanges = 2 miles

8% trucks and 2% RV

Right shoulder lateral clearance = 5 ft

BFFS = 70

Problem 2

1. Determine the level of service for a 3000 ft segment of a four –lane highway with 3% grade, 45 mph field measure, 11 ft lanes, 0.88 PHF, 15% trucks and 4%. Assume one way peak hour volume is 2200 vehicles/hour and the traffic consists of commuters.

Problem 3

Based on an entry-exit record in a gated parking lot, 275 cars parked during a typical day between 9 am and 6 pm. Of these cars 10% were parked for 1 hour, 35% for 2 hours, 25% for three hours and the remaining for 4 hours. About 15% of the bays are vacant on an average throughout the day. If the efficiency factor is 80 %, what is the space-hour demand and the number of parking spaces in the lot

Answer 1

1) Given, Base free flow speed (BFFS) = 70 mph

Lane width = 11 ft

Reduction in speed corresponding to lane width, f_LW = 1.9 mph

Lateral Clearance = 5 ft

Reduction in speed corresponding to lateral clearance, f_LC = 0.4 mph

Interchanges/Ramps = 1 /2 miles = 0.5/ mile

Reduction in speed corresponding to Interchanges/ramps, f_ID = 0 mph

No. of lanes in each direction = 3

Reduction in speed corresponding to number of lanes, f_N = 3 mph

Free Flow Speed (FFS) = BFFS – f_LW – f_LC – f_N – f_ID= 70 – 1.9 – 0.4 – 3 – 0 = 64.7 mph

Assume, Peak Flow, V = 2500 veh/hr

Peak-hour factor = 0.90

Trucks and buses = 8 %

RVs = 2 %

Level Terrain

f_HV = 1/ (1 + 0.08 (2.5-1) + 0.02 (1.2-1)) = 1/1.14 = 0.877

f_P = 1.0

Peak Flow Rate, V_p = V / (PHV*n*f_HV*f_P) = 2500/(0.90*3*0.877*1.0) = 1055.59 ~ 1056 veh/hr/ln

S = FFS = 64.7 mph

Density = V_p/S = (1056) / (64.7) = 16.32 veh/mi/ln

LOS B

Density of LOS B lies between 11-18 veh/mi/ln