Traffic flow on a section of a two-lane highway can be described by the Greenshields model, with a mean free speed of 54 mi/h and a jam density of 146 veh/mi/In. At the time when the flow was 90 percent of the capacity of the highway, a large dump truck loaded with heavy industrial machinery from an adjacent construction site joins the traffic stream and travels at a speed of 11 mi/h for a length of 3.5 mi along the upgrade before turning off onto a dump site. Due to the relatively high flow in the opposite direction, it is impossible for any car to pass the truck. Determine how many vehicles will be in the platoon behind the truck by the time the truck leaves the highway. vehicles Need Help? Read It Watch It

Traffic flow on a four-lane (one direction) freeway can be described by the Greenshields model. Two lanes of the four lanes on a section of this freeway will have to be closed to undertake an emergency bridge repair that is expected to take 2 hr. The mean free speed of the highway is 60 mi/h and the jam density is 140 veh/mi/ln. If it is estimated that the demand flow on the highway during the emergency repairs is 80% of the capacity, using the deterministic approach, determine: (a) The maximum queue length that will be formed (b) The total delay(c) The number of vehicles that will be affected by the incident(d) The average individual delay

The traffic demand for a six-lane urban arterial road (three lanes per direction) is given in the table below. The relationship between flow and density for this road follows GreenShiled's model, with a free flow speed of 105 km/h and a jam density of 92 veh/km/lane. Two of the three lanes of the EB direction were closed at 5:00 AM for maintenance. The two lanes were re-opened at 8:00 AM, allowing the traffic to be released at capacity conditions. a) What is the maximum length of the queue upstream of the bottleneck? b) At what time the queue upstream of the bottleneck will be fully dissipated? c) What is the furthest point upstream of the bottleneck that will be impacted by the lane closure? d) Draw the shock wave diagram showing shock wave speeds, critical times, and distances. Time 5:00 6:00 AM 6:00 7:00 AM 7:00 8:00 AM 8:00 9:00 AM 9:00 10:00 AM 10:00 11:00 AM Demand (vph) 2000 4000 6400 6000 3600 3000

Question A linear relationship is observed between speed and density on a certain section of a highway. The free flow speed is observation to be 80 km per hour and the jam density is estimated as 100 vehicles per km length. Based on the above relationship, the maximum flow expected on this section and the speed at the maximum flow will respectively be

Traffic flow on a three-lane (one direction) freeway can be described by the Greenshields model. One lane of the three lanes on a section of this freeway will have to be closed to undertake an emergency bridge repair that is expected to take 2 hours. It is estimated that the capacity at the work zone will be reduced by 35 percent of that of the section just upstream of the work zone. The mean free flow speed of the highway is 50 mi/h and the jam density is 115 veh/mi/In. If it is estimated that the demand flow on the highway during the emergency repairs is 85 percent of the capacity, using the deterministic approach, determine the following. (a) the maximum queue length (in veh) that will be formed Your response differs from the correct answer by more than 10%. Double check your calculations. veh (b) the total delay (in h) h (c) the number of vehicles that will be affected by the incident veh (d) the average individual delay (in min) min

Traffic flow on a three-lane (one direction) freeway can be described by the Greenshields model. One lane of the three lanes on a section of this freeway will have to be closed to undertake an emergency bridge repair that is expected to take 2 hours. It is estimated that the capacity at the work zone will be reduced by 35 percent of that of the section just upstream of the work zone. The mean free flow speed of the highway is 60 mi/h and the jam density is 125 veh/mi/ln. If it is estimated that the demand flow on the highway during the emergency repairs is 90 percent of the capacity, using the deterministic approach, determine the following. (a) the maximum queue length (in veh) that will be formed  Your response is within 10% of the correct value. This may be due to roundoff error, or you could have a mistake in your calculation. Carry out all intermediate results to at least four-digit accuracy to minimize roundoff error. veh (b) the total delay (in h)  Your response differs…

Traffic flow on a three-lane (one direction) freeway can be described by the Greenshields model. One lane of the three lanes on a section of this freeway will have to be closed to undertake an emergency bridge repair that is expected to take 2 hours. It is estimated that the capacity at the work zone will be reduced by 25 percent of that of the section just upstream of the work zone. The mean free flow speed of the highway is 60 mi/h and the jam density is 140 veh/mi/ln. If it is estimated that the demand flow on the highway during the emergency repairs is 85 percent of the capacity, using the deterministic approach, determine the following.  the maximum queue length (in veh) that will be formed  the total delay (in h) the number of vehicles that will be affected by the incident  the average individual delay (in min)

Ex2/ The speed density relationship of traffic on a section of free way lane was Vs =18.2ln 220 1- what is the max flow, speed and density at this flow ? 2- what is the jam density ?

The relationship between flow and density on a four-lane highway (two lanes per direction) is known to follow GreenShiled's model, with a free flow speed of 100 km/h and a jam density of 80 veh/km/lane. One of the two lanes of the EB direction will be closed for an entire month for maintenance. The traffic demand for the highway on a typical weekday is shown in the table below. a) What is the maximum length of the queue upstream of the bottleneck during both the morning and afternoon peak hours? b) At what time will the morning and afternoon queues be dissipated? c) Draw the shock wave diagram (for the entire day) showing shock wave speeds, critical times, and distances. Time 7:00 AM - 9:00 AM 9:00 AM 3:00 PM 3:00 PM 7:00 PM 7:00 PM–11:00 PM 11:00 PM 7:00 AM Average Demand (vph) 3000 1500 3200 1200 400

Traffic & Highway Engineering Chapter 6 question 6-18