Problem 2 Speed data collected on an urban roadway yielded a standard deviation in speeds of ± 5.1 mi/h.

Due to improvements in highway ITS assets, the average truck operating speed on a certain interstate freeway increased from 57 to 62 mph. Find the decrease in shipping inventory costs per year for trucks that comprise 30% of the overall traffic stream of 75,500 vpd. On the average, each truck hauls an average of $2.2 million worth of goods daily. Assume an 7% interest rate

The injury crash rate with and without improvement project at a rural two-lane highway is 2.87 and 3.5 per million VMT. Determine the user safety benefit in monetary terms due to reduction in crash rate. Assume average vehicle occupancy=1 and annual VMT is 1.5 and 1.8 millions for before and after improvement scenarios. Unit Cost of incapacitating Injury = 181,276 (2005 $).

Traffic for a future roadway is projected to be AADT = 15000 vehicles. Vehicle distribution and thecorresponding ESAL factors are given in Table 1. 1. Using a growth factor of 3%, estimate traffic in the design lane, in ESALS, for a design life of 30years. 2. The subgrade soil is a high plasticity clay (CH). The available base and sub base materials have R-Values of 75 and 50, respectively. Design a conventional flexible pavement structure using the 1 993 AASH TO method. Clearly state all assumptions made.

3. (10 points) Please read the readings and answer the following questions: a. Can we always improve the traffic conditions by building extra roads in our traffic network? Circle your answer. TRUE or FALSE b. Why did New York City decide to close the 42d Street?

9. (15 points) There are three routes between O and D, two Traffic Analysis Zones, as shown in the figure below. The total travel demand from O to D is 10,000 vehicle trips during a study period. Table 10-1 shows the attributes for each link, including the capacity, free flow speed,segment length, and BPR formula (or volume-delay function) parameters (a and B). The BPR function is shown below, a) Use the All-or-Nothing method (non-incremental) to determine the traffic assignment on three links. t_{i}=t 0_{i}\left(1+\alpha\left(\frac{v_{i}}{c_{i}}\right)^{\beta}\right) t= Congestion flow travel time on link i; t0i= Free-flow travel time on link i; vi = Volume of traffic on link i per unit of time (flow attempting to use link i); Ci= Capacity of link i per unit of time; a= Alpha coefficient, which was assigned a value of 0.15 in the original BPR curve; and B= Beta coefficient, the exponent of the power function,which was assigned a value of 4 in the original BPR curve b) Use the Incremental All-or-Nothing method to assign the traffic on three links (use 1000 increments).

6. (5 points) What is the minimum radius for a two-lane highway if the maximum superelevation emax = 7 %, side friction fs = 0.10, and the design speed is 65 mph?

5. (5 points) What is the key difference between Running Speed and Travel Speed?

A car traveling at 70 mph on a 5% downgrade skids 350 ft before striking a retaining wall head-on. The coefficient of friction between the tires and the road is 0.30. What was the approximate speed of the car atimpact?

4. (5 points) What are the advantages and limitations of Growth Factor Methods?