Traffic Analysis Zone

Class Project

The purpose of this project is to engage students in an application of the 4-step urban travel demand forecasting process. This project will not only engage students in a group work environment, but also improve their understanding in predicting travel demand and planning for the future. This project is important because it reinforces a large portion of the key elements covered during this course.

Each group must do its own independent work. Penalties may be imposed on groups that collaborate on this project. Sharing results, spreadsheets, etc. is not allowed. If you have difficulties, please ask the instructor.Projects submitted after the deadline will NOT be accepted under ANY circumstances.

 

BACKGROUND

Your team has been hired to forecast travel demand for a small urban area with population of 50,000 consisting of four traffic analysis zones connected by a network of major highways. Your team is to conduct both base- and target-year analyses using the 4-step travel demand forecasting process as a means to predict both current and future urban travel demand for the area in consideration. Students must use Excel spreadsheets for the four steps.

TAZIncomeNumber ofCBD RENCBD RESEOE
Category HH
1Low680001679620425
Medium3000
High800
2Low46500215037575
Medium2650
High755
3Low8000245000
Medium4700
High3850
4Low8003150021001660
Medium3000
High2100
Legend:
HHHousehold
RERetail Employment 
SEService Employment
OEOther Employment

 

STUDY AREA

1
3
2
4

 

 

 

 

T=22 min; C=5,000                             T=12 min, C=4,000

 

                   T=35 min; C=5,000

 

 

T=19 min; C=6,000                               T=11 min; C=2,000

 

 

TRIP GENERATION

In your analyses, consider three types of trips: HBW, HBO, and NHB. For calculation of productions and attractions, use the TRB Trip Generation handout. Clearly note in your final report which table(s) or equation(s) from the handout was used. Consider TAZ 4 as CBD and the other TAZs as suburban. After estimation, balance the HBW, HBO, and NHB productions and attractions.

TRIP DISTRIBUTION

In order to utilize the recommended values in your calculations, use the TRB Trip Distribution handout for this step as well. Assume travel times in both directions on a link the same (i.e., travel time from 2 to 3 is the same as 3 to 2) and ignore external traffic (i.e., assume all traffic internal-to-internal). Use the average travel time of the links connected to a zone for intrazonal travel time and the FHWA gamma function for deriving friction factors. Apply the Gravity model to all three different trip types in consideration. In order to determine travel times between zones, assume travelers will choose minimum paths (measured by travel times) between zones. Make sure total travel times include both link travel times and terminal travel times.

After application of the Gravity model for different trip types, balance both productions and attractions by performing two balancing iterations each on columns and rows.

Finally, convert trip end (P-A) matrices to origin-destination (O-D) matrices by taking the average of  trips.

MODE CHOICE

Assume no other viable transport mode exists in the study area other than automobiles.

 

TRAFFIC ASSIGNMENT

For conversion of person trips to vehicle trips, auto occupancy conversion factors for each trip type are as follows:HBW: 1.11, HBO: 1.67, and NHB: 1.66

Assume 30% of the three trip types (HBW, HBO, and NHB) occur during the peak hour. Also auto traffic should be assigned based on travel times resulting from capacity restraint traffic assignment methodology using 40%, 30%, and 30% increments.

TARGET-YEAR ANALYSIS

Each group will conduct future-year analysis. Assume population and employment will increase by 2.5 and 2.2 times, respectively. Also, assume the growth will be uniform across the study area.

FINAL REPORT

Each group will prepare a report describing the complete process. The report will include at the minimum a table of contents, an executive summary, introduction or background, main text (describing what each group did, divided into several sections/subsections), conclusions and recommendations, reference section, and appendices. Summarizing information in tables, graphs, and figures, is highly desirable. Detailed or sample calculations may be included in appendices. Each group should justify why a particular value or procedure was chosen and provide reference(s), if any. A reference section should be included between the main body of the text and appendices. Each group will include a CD with the spreadsheets that were developed for the projects (this will enable the instructor to locate mistakes, if any).

 

Last Updated on April 28, 2019

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