Updated methods for traffic impact analysis, including evaluation of innovative intersection designs

Gerald Thomas Bollinger, Purdue University

Abstract

In 1992, Dr. Jon Fricker and Soumya Dey published both an Applicant's and Reviewer's Guide to Traffic Impact Analyses to standardize the methodologies for conducting traffic impact analyses (TIAs) in Indiana for the Indiana Department of Transportation (INDOT). The methodologies were meant to help streamline the process of preparing and reviewing TIAs. The methodology is applicable for other transportation and government entities as well. Now that 20 years have passed since the publication of the guides, INDOT wishes to: • evaluate how effective the guides have been, • determine what in the guides has worked well, • revise parts of the guides that have not worked well, and • add improvements and changes that have occurred since the guides' publication. The guides were evaluated by collecting survey responses from INDOT personnel, LPAs and consultants involved in the TIA process. A number of recommended changes to the guides are presented, including updates to the scoping meeting outline and requiring TIAs to be conducted by traffic engineers licensed in Indiana. Brief explanations of the innovative intersection alternatives of roundabouts, median U-turns (MUT), restricted-crossing U-turns (RCUT), displaced left-turns (DLT), and quadrant roadways (QR) have been provided to increase awareness of and provide some criteria for when to consider these possible designs. When conducting a TIA, these innovative designs may be viable alternatives. Some of the innovative designs were compared against a two-way stop-controlled intersection and a conventional signalized intersection for varying minor street approach volumes. The median U-turn design seemed to perform better at higher, more balanced flows whereas the roundabout performed better for unbalanced flows. An attempt was made to compare visually confirmed internal trips to the internal trips predicted using each store's individual land use code in ITE Trip Generation. At times, a development affects roads in more than one jurisdiction. Ideas are presented that may facilitate the inclusion of all affected parties early in the development process to improve communication, address all possible effects of the development and better satisfy all affected parties.

Degree

M.S.C.E.

Advisors

Fricker, Purdue University.

Subject Area

Civil engineering

COinS