Purdue University
School of Civil Engineering
CE 361 Introduction to Transportation Engineering
Homework 3
CAPACITY, DELAY, AND TRAVEL MODELS
Out: Wed. 17 September 1997
Due: Fri. 26 September 1997
Problem 2 reworded on 22 September 1997
Dear Consultant:
Please demonstrate your ability to apply a variety of Travel Demand
Modeling techniques by completing the problems listed below.
Some of the solutions are sensitive to the precision of intermediate
calculations,
so use at least three significant figures in these cases.
We in the Mythaca County Engineer's office
will also be evaluating the clarity and conciseness with
which you complete the assigned problems.
Use of a spreadsheet is encouraged whenever appropriate.
In any case, show enough sample calculations to demonstrate to us that
your procedure is correct.
Reminder: You must give each problem a descriptive heading or title.
-
Highway Capacity.
A formerly rural portion of Mythaca County has become a popular location for
residential and commercial development.
The principal access to this area is county road (CR) 545,
which does not meet modern highway design standards.
CR545 is a rural two-lane road that winds through rolling terrain.
Our staff has determined that passing is permitted on CR545 only 46 percent of the time.
During afternoon peak periods,
about 84 percent of the traffic is in the direction of the new development.
The traffic lanes are each 11 feet wide,
with a gravel shoulder about 2.5 feet wide.
During the afternoon peak,
there are no buses on CR545, but 6.6 percent of the traffic stream is trucks
and 2 percent are RVs.
-
A.
(10 points)
The County staff wants to use SF(E) as the capacity of CR545 in their peak period
Travel demand model.
What is this value?
Show clearly how you determined the value of each adjustment factor.
-
B.
(5 points)
If the current 2-way flow on CR545 is 723 vph during the afternoon peak period,
what is the corresponding LOS?
(Use the same traffic stream characteristics as in Part A.)
-
(10 points)
Intersection Delay.
Compute the average stopped time delay (HCM equation 11-3) for
the LT lane on EB Coliseum Avenue at Wakefield Street for both the
"peak" and "off-peak" periods.
(See HW2, Problem 3.)
The cycle is 60 seconds long and the LT lane gets only 8 seconds of "effective green time".
Assume the LT lane has a capacity of 1445 vph,
and that the HCM equation applies to the LT lane's operation.
-
(10 points)
Review of CNotes Chapter 8.
A thoughtful, honest, coherent response to each of the four items below is expected.
-
A. Is the general level of the presentation in Chapter 8
too simple, too difficult, or about right for you?
-
B. Which sections were the most helpful in understanding the material?
-
C. Which sections were confusing or otherwise inadequate?
Elaborate briefly.
-
D. If you found typographical or other errors, where were they?
-
(10 points)
Trip Generation.
Do MK Problem 7.3.
Include in your answer the change in total number of trips in the zone.
-
(10 points)
Trip Generation by ITE Method.
Memorial Hospital in Mythaca
is an example of a special generator.
Use pages 885 and 896 in the ITE T/G report (SNotes Section 3.2)
to produce values for
the number of trip ends the site can be expected to generate during
two time periods:
the average weekday and
the weekday PM "adjacent street peak".
The values of certain independent variables are given in
the following table.
For each time period and variable,
use both the rate and fitted equation to calculate T values.
Then decide upon a single T value for each period
and explain why you chose the value you did.
|
Variable
|
MMH value
|
|
Beds
|
187
|
|
Employees
|
610
|
|
Gross Floor Area (1000s sq ft)
|
267
|
-
(10 points)
Trip Distribution.
Do MK Problem 7.7, but
use the Gravity Model with
F(ij) = t(ij)^(-1.25),
where t = travel time (minutes).
Assume A(j) = Commercial Floor Space
and average travel speed = 15 mph.
Use the tabular format shown in SNotes Section 3.3
and CNotes Table 8.3.
-
(10 points)
Mode Choice.
A sudden increase in disposable income and tourism around Shoridan has made the
hovercraft and helicopter rides across Murdoch Bay (CNotes Ex. 8.4) very popular.
In fact, there seems to be a market for hot air balloon rides as a third
"travel mode" during Shoridan's upcoming Fall Foliage Festival.
Balloon rides will cost $76.30,
take an average of 21 minutes for queueing and check-in (OVTT), and
take an average of 41 minutes to float across the bay.
If the mode-specific constant for hot air balloon is a(0,hot) = 0.45,
estimate the mode share for all three modes this Fall.
-
(10 points)
Route Choice (Trip Assignment).
Do MK Problem 7.20.