Effective Capacity Analysis and Traffic Data Collection for the I-85 HOV to HOT Conversion


Kate D'Ambrosio, Graduate Student, Georgia Tech
Dr. Randall Guensler, Professor, Georgia Tech
Dr. Michael Hunter, Associate Professor, Georgia Tech
Dr. Jorge Laval, Assistant Professor, Georgia Tech
Dr. Angshuman Guin, Research Engineer II, Georgia Tech
Vetri Elango, Research Engineer I, Georgia Tech

Project Overview:

In many urban areas, traffic congestion cannot be alleviated through the addition of lanes due to the lack of available right-of-way.  The current high-occupancy (HOV) lanes on I-85 experience recurrent congestion consistent with congestion on the adjacent general purpose lanes, usually with a minor delay in congestion onset.  The replacement of the HOV lane with a new HOT (High Occupancy Toll) lane is designed to alleviate the congestion currently experienced in the HOV lane and provide a reliable trip time through the corridor. In the new HOT lane, vehicles with three or more occupants can ride for free while vehicles with one or two occupants can pay a toll to use the lane. Variable pricing will be used based off demand and capacity of the lane to provide a reliable trip time throughout the day.

The effectiveness of the implementation of the HOT lane is being evaluated in this before and after study.  Traffic volume and speed data are being archived as well as field collection of vehicle occupancy and license plate data (for demographic studies). These data will provide information about who is using the carpool and general purpose lanes before and after HOT lane implementation. Data are being collected eight times over a two year period at five sites along the I-85 corridor from Chamblee-Tucker Road to Old Peachtree Road.