Question

In: Civil Engineering

Traffic on a three-lane freeway observes a triangular flow-density relationship with free-flow speed vf=100km/h, capacity c=2000veh/h/lane,...

Traffic on a three-lane freeway observes a triangular flow-density relationship with free-flow speed vf=100km/h, capacity c=2000veh/h/lane, jam density kj=150veh/km/lane. Flow in the freeway from upstream is 5000veh/h, while the ramp flow is negligible (almost zero).At 9:45am, an accident occurs at point A. The vehicles involved close one lane of traffic (total capacity reduces to 4000veh/h) for 15min and afterwards the scene is clear (capacity returns to 6000veh/h). Lucy enters the freeway via the ramp at point B at 10:00am. Distance AB is equal to 6.5km.What time [h] does Lucy leave the queue?What time [h] does Lucy pass the accident scene (point A)?

Solutions

Expert Solution



Related Solutions

Consider a freeway with two lanes and capacity of 2000 veh/h/lane, jam density of 60 veh/km/lane...
Consider a freeway with two lanes and capacity of 2000 veh/h/lane, jam density of 60 veh/km/lane and a triangular fundamental diagram. Traffic is moving with the flow of 3000 veh/h and the space mean speed of 100 km/h. At 10:00 a.m., a traffic crash occurs that blocks one lane for half an hour. Using shockwave analysis, answer the following questions. a. Draw the space-time diagram with shockwaves and traffic states (trajectories not needed). [2 marks] b. At time t =...
Assume the speed and density at a freeway location follows a linear relationship.You observe traffic flow...
Assume the speed and density at a freeway location follows a linear relationship.You observe traffic flow rate of 2250 vehicles/hour at 45 mph and 3000 vehicles/hour at 30 mph. What are the jam density, free flow speed (max speed), and capacity of this freeway location? How about the density and speed (i.e., the critical density and the critical speed) at the capacity?
TRP 631: HIGHWAY TRAFFIC OPERATIONS An existing six-lane divided multilane highway with a field-measured free-flow speed...
TRP 631: HIGHWAY TRAFFIC OPERATIONS An existing six-lane divided multilane highway with a field-measured free-flow speed of 45 mi/h serves a peak-hour volume of 4,000 veh/h with 10% trucks (50% SUT, 50% TT). The PHF is 0.88. The highway has generally rolling terrain. What is the likely level of service of this segment? Good weather, no incidents, no work zones, and regular drivers may be assumed.
A freeway is being designed for a location in mountainous terrain. The expected free-flow speed is...
A freeway is being designed for a location in mountainous terrain. The expected free-flow speed is 88.5 km/h. Lane widths will be 3.6 m and shoulder widths will be 1.8 m. During the peak hour, it is expected there will be a directional peak- hour volume of 2700 vehicles, 12% large tracks and buses and 6% recreational vehicles. The PHF and driver population adjustment are expected to be 0.88 and 0.90, respectively. If a level of service no worse than...
Transportation: Which is more significant in reducing free flow speed on a freeway, narrower lanes or...
Transportation: Which is more significant in reducing free flow speed on a freeway, narrower lanes or a narrower right side shoulder? Does this make sense to you? Why?
A six-lane freeway (three lanes in each direction) operates at capacity during peak hour. It has...
A six-lane freeway (three lanes in each direction) operates at capacity during peak hour. It has 11-ft lanes, 4-ft right shoulders, and there are three ramps within three miles upstream of the segment midpoint and four ramps within three miles downstream of the segment midpoint. The freeway has an AADT of 60,000 veh/day. The traffic stream has 8% heavy vehicles, and it is on rolling terrain with a peak- hour factor of 0.85. It is known that 12% of the...
4. A six-lane freeway (three lanes in each direction) operates at capacity during peak hour. It...
4. A six-lane freeway (three lanes in each direction) operates at capacity during peak hour. It has 11-ft lanes, 4-ft right shoulders, and there are three ramps within three miles upstream of the segment midpoint and four ramps within three miles downstream of the segment midpoint. The freeway has an AADT of 60,000 veh/day. The traffic stream has 8% heavy vehicles, and it is on rolling terrain with a peak- hour factor of 0.85. It is known that 12% of...
. In three sentences or less, explain why traffic density and speed are related.
. In three sentences or less, explain why traffic density and speed are related.
Assuming a linear speed-density relationship. the mean free speed is observed to be 65 mph at...
Assuming a linear speed-density relationship. the mean free speed is observed to be 65 mph at near zero density and the corresponding jam density is 160 veh/mi. Assume that the average length of vehicles is 20 feet. a) Write down the equations for speed-density and flow-density relationships b) Calculate the speed and density corresponding to a flow of 1000 veh/hr c) Calculate the average time headway and average space headway when the traffic flow is at maximum value
A section of highway has the following flow-density relationship, where flow (q) is in veh/h and...
A section of highway has the following flow-density relationship, where flow (q) is in veh/h and density (k) is in veh/km. ? = 60? − 0.24? 2 What is the speed when the highway is at 50% of its capacity and the traffic is in uncongested conditions? [5 marks]
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT