Developing Efficiency Attributes for Right-Turn Flashing Yellow Arrow on Impeding through and Opposing Left Phases Using a Multinomial Logit Model

Abstract

The right-turn flashing yellow arrow (FYA) signal display is still considered a new signal practice in the United States. The Manual on Uniform Traffic Control Devices (MUTCD; 2009) allocates a signal phasing section for the right-turn FYA, which requires a four-section configuration. It supports multiple phase indications that guide the motorists through permissive, protected, or permissive or protected phases. However, there are no right-turn FYA or protected permissive right turn (PPRT) guidelines in place with a focus on operational efficiency. In this paper, we investigated two permissive right-turn FYA phases in various traffic conditions and signal timing plans. The first permissive right-turn FYA phase is the right turn on impeding through (RTOIT) taking place during cross-street through movement. The second permissive right-turn FYA phase occurs during opposing left-turn movement and is thus called right turn on impeding left (RTOIL). We aimed to develop warrants leading to the efficient implementation of permissive right-turn FYA phases based on a microsimulation analysis. The response, the average maximum right-turn throughput (MRTT) per cycle, was categorized into three categorical variables represented as the nonefficient (NE), low efficient (LE), and efficient (E) categories depending on the number of executed right turns per cycle. A multinomial logit model was developed to establish a decision support system that predicts the efficiency attributes of the permissive RTOIT and RTOIL FYA phases that can help traffic management center operators in planning and operational-level applications.