Doctoral Dissertations

Date of Award


Degree Type


Degree Name

Doctor of Philosophy


Civil Engineering

Major Professor

Lee D. Han

Committee Members

Stephen H. Richards, William L. Seaver, Frederick J. Wegmann


Right turn on red (RTOR) is an established part of today’s driving patterns. However,despite several revisions of the Highway Capacity Manual (HCM), the procedures for estimating delay at signalized intersections do not adequately incorporate the effects of RTOR. The HCM currently removes RTOR from the analysis.

This dissertation has developed models of uniform delay that incorporate RTOR based on queuing theory. Queuing accumulation polygons (QAP) were developed that include RTOR. The research developed a classification system for describing any signal phasing into one of 4 classes based on the sequence of 3 red regimes and one green regime.

It was further demonstrated that these 4 classes of signal phasings resulted in one of 2 general QAP patterns. The first pattern consists of two conflicting regimes followed by two nonconflicting regimes. The other pattern consists of alternating conflicting and non-conflicting regimes. Models to calculate delay for each basic pattern were developed.

The performance of the proposed models was evaluated with both field data and simulated data. The proposed model predicted delays that were different from both the observed delays and the delays based on the HCM method. A review of the intermediate calculations and videotape data suggests that variations in driver behavior may may partially account for the difference between the observed delay and the predicted delay.

Data sets were generated by varying volume parameters and signal timing parameters. The first data set simulated a variety of traffic conditions at the study intersection. The second data set represents as a variety of volumes under different signal timing patterns for a 4 phase timing plan. The proposed model predicted reductions in delay over a wide range of conditions when compared to the HCM approach under both sets of conditions.

Files over 3MB may be slow to open. For best results, right-click and select "save as..."