High Occupancy Vehicle (HOV) lanes are employed in many cities as a traffic congestion mitigation technique. These lanes are intended to provide a travel time benefit to carpools and buses, thus providing an incentive to form carpools or take transit. The time and frustration involved in finding and using HOV lane access points may act as a deterrent to HOV lane use. Thus, proper planning of HOV lane access may be able to improve convenience for potential users, increasing HOV lane utilization. By optimizing HOV lane volumes, high levels of service and trip reliability are ensured for those who carpool. Congestion is also reduced on General Purpose Lanes (GPLs) due to the diverted traffic. Public approval is tied to HOV lane utilization, which may be affected by access. Thus, HOV lane success may be determined in part by accessibility. This research investigated the possible relationship between the time required to access the HOV lane and travelers' choice of HOV lane as their mode. Additionally, the distance to HOV lane access points and the type of access point used were examined for their influence on HOV lane use rates. It was concluded that neither the type of HOV lane access point, nor the added time necessary to access the HOV lane were significant factors in HOV lane use rates. Instead, the convenience of carpool formation and the convenience of HOV lane access to traveler's origins and destinations were found to be the most important factors in HOV lane use rates. Specifically, the HOV lane use rate for the area 5 to 7 miles from the nearest HOV lane exit, which includes Downtown Houston, was much higher than the use rates for any other area.

Managed lanes are a form of congestion pricing that use occupancy and toll payment requirements to utilize capacity more efficiently. How socio-spatial characteristics impact users’ travel behavior toward managed lanes is the main research question of this study. This research is a case study of the conversion of a High Occupancy Vehicle (HOV) lane to a High Occupancy Toll (HOT) lane, implemented in Atlanta I-85 on 2011. To minimize the cost and maximize the size of the collected data, an innovative and cost-effective modeling framework for socioeconomic analysis of managed lanes has been developed. Instead of surveys, this research is based on the observation of one and a half million license plates, matched to household locations, collected over a two-year study period. Purchased marketing data, which include detailed household socioeconomic characteristics, supplemented the household corridor usage information derived from license plate observations. Generalized linear models have been used to link users’ travel behavior to socioeconomic attributes. Furthermore, GIS raster analysis methods have been utilized to visualize and quantify the impact of the HOV-to-HOT conversion on the corridor commutershed. At the local level, this study conducted a comprehensive socio-spatial analysis of the Atlanta I-85 HOV to HOT conversion. At the general scale, this study enhances managed lanes’ travel demand models with respect to users’ characteristics and introduces a comprehensive modeling framework for the socioeconomic analysis of managed lanes. The methods developed through this research will inform future Traffic and Revenue Studies and help to better predict the socio-spatial characteristics of the target market.