Date on Master's Thesis

4-2026

Document Type

Master's Thesis

Degree Name

M. Eng.

Department

Civil and Environmental Engineering

Committee Chair

Kluger, Robert

Committee Member

Bai, Lihui

Committee Member

He, Yueshuai

Author's Keywords

Comparative analysis; before-and-after study; Northern Kentucky; traffic impact study; high-resolution signal data; traffic forecasting

Abstract

Traffic forecasting and modeling has been a significant subject of debate within the transportation sector as of the last decade. Transportation agencies and planners use traffic forecasting and modeling in order to predict current and future transportation needs, as well as the impacts of proposed developments. In particular, state departments of transportation (DOTs) and city level agencies often require developers to conduct Traffic Impact Studies (TISes) in order to gauge necessary transport network enhancements to handle new demand from proposed developments. The standards by which these TISes are conducted and judged varies widely, but primarily consists of existing traffic counts, predicted future growth rates, predicted traffic generated by the development, and computer analysis of traffic system operations and conditions. These simulations create a Level of Service (LOS) measurement, used to quantify the level of traffic congestion on the roadway. Agencies can reject a proposed development on the basis of a worsening of LOS predicted and often require developers to pay for roadway improvements as compensation for additional traffic generated. Much debate and study has been had about the accuracy of these TISes and traffic simulations. The principal tool used to calculate generated traffic by a proposed development is the Institute of Transportation Engineering (ITE) Trip Generation Handbook. This document, updated periodically, has been used for decades to calculate generated traffic and is the officially sanctioned method of doing so by many agencies, including the Kentucky Transportation Cabinet (KYTC). However, the ITE Handbook has potential shortfalls. It has been slow to adapt to mixed use developments – developments containing multiple different land uses and has little capacity to adjust to variations in trip generation and mode share between urban, suburban, and rural environments. The ITE Handbook and TIS guidelines assume that 95% - 100% of trips generated use automobile travel, even in dense urban areas. Many proposed developments in urban areas have had to be canceled or scaled back due to concerns about traffic impacts, including under this system. This thesis sets out to study the accuracy of KYTC approved TISes. In this thesis, thirty-two intersections across Northern Kentucky were analyzed. TISes from the past several years were compared to real traffic counts taken in October 2025, to gauge the accuracy of TIS predictions of traffic. Linear Regression was the principal model used to compare before & after counts. Total traffic counts, specific intersection movements, individual signal phases, and peak hour factors were compared for accuracy. It was found that the TISes studied often overestimated traffic to varying degrees, with a smaller amount being accurate or an underestimate. Further research is necessary to potentially develop adjustments or improvements to the ITE Handbook to improve TIS accuracy.

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