Test 2 Solutions
Step 1: Estimate the Free-Flow Speed
fLS = 3 (Tab. 16.5)
Total access points per mile on each side =
1 acc. pt. 5280 ft
On both sides = 4.4 x 2 = 8.8 acc. pt/mile
f A 8.8 0.25 2.2 mi / h (or Table
Alternate Test 1
3. What is the average speed of vehicles on the freeway during the study period?
4:00 pm - 4:15 pm
4:15 pm - 4:30 pm
4:30 pm 4:45 pm
4:45 pm 5:00 pm
Step 1: Determine the free-flow speed
Speeds were collected on one lane of a freeway and are provided below and in the attached excel
spreadsheet. Show final equations used.
For this data determine the mean, median, 85th percentile speed and the
standard deviation of the speeds.
1. A roadway has on average 5 crashes per mile during a year.
a. If the number of crashes are assumed to follow a Poisson distribution, what is the
probability that more than 5 crashes occurs within a one-mile segment of the
roadway during a year?
An accident occurs at 4:00 pm on a four-lane highway closing two lanes for 30 minutes. At 4:30
pm, one of the closed is reopened and the second lane remained closed for another 30 minutes.
The demands for the freeway section under construction a
A Class I two-lane highway is located in rolling terrain and has a base free-flow speed of 60 mph
and 40 percent of the segment consists of no-passing zones. The cross-section has 12-ft lanes
and 3-foot shoulders on both sides of the road. There is an ave
In the diagram below, a weaving section is created by vehicles entering Ramp A and vehicles
exiting Ramp B. Assume 150 pcph that enter Ramp A exit Ramp B. The short length of the
weaving section is 2000 feet. The freeway is on level terrain and the interc
The freeway shown below has 12-foot lanes, adequate lateral clearances, level terrain,
and is used primary by commuters. What is the level of service of the Ramp B junction?
(Hint: The freeway volume at Ramp B includes the freeway volume at Ramp A plus th
1. An undivided six-lane multilane highway has an 85th percentile speed of 60-mph with the
volumes in one direction of the roadway during the AM peak hour shown in the table below.
The highway has 11-foot lanes, no shoulders, and is located in rolling ter
1. Construction is planned in the eastbound direction of an eight-lane rural freeway in New
Jersey. The existing freeway has 12-foot lanes, 4-foot shoulders on both the right and
median side of the roadway and has a posted speed limit of 65 mph. There are
A study of freeway flow at a particular site has resulted in a speed-flow relationship, as follows:
F 45S 0.6S 2
a. From this relationship determine speed-density and flow-density relationships.
b. What is the capacity of the freeway?