Life-Cycle Graphical Representation of Managed High-Occupancy Vehicle Lane Evolution

Abstract

High-occupancy vehicle (HOV) lanes usually go through an evolution of stages in their life cycle. The typical evolution includes changes in demand levels from several modes including 2+ or 3+ carpools and vanpools, transit, and general-purpose vehicles. To ensure adequate usage, most facilities have started out with a designation of HOV2+. In some cases, over time, HOV2 volumes have exceeded the capacity of the facility, which has caused delays for transit vehicles. Therefore, there is an inevitable need for managing the hierarchy of facility users over time. A graphical tool is presented that indicates the life span of a managed HOV lane, and it can be applied to a variety of existing and planned managed HOV lane projects. The graphic was used in Colorado, Florida, and Texas in communicating the managed lane concept to transportation professionals. Further, the graphic was used to explain the historical operation of a managed HOV lane facility and the likely progression if current management policies remain in effect, based on experiences in similar facilities. Alternative management strategies can also be evaluated and compared with the graphical tool. The graphical representation of this managed HOV lane concept is anticipated to be valuable for transportation professionals in many areas (e.g., highway, tolling, and transit) in presenting and understanding operating scenarios for managed lanes over time and how they meet the goals of the facility. Applications of the life-cycle graphic to various facilities in the United States are also presented.

Accessibility Futures

“…According to Swisher et al. (), the critical operating threshold for a single HOT lane is 1,300 vehicles/hour (ensuring a very low probability of congestion and resulting speed drops). An often‐used value for the capacity of a general‐purpose freeway lane is 2,000 vehicles/hour.…”

Impact of TDM on Managed Lanes Toll Prices

“…Most recently, carpooling declined from 10.7 percent in 2003 to 9.7 percent in 2012 both in Florida and nationwide (Florida Department of Transportation, 2013). With carpool rates having dropped, HOT lanes have evolved as a way to make better use of unused capacity (Swisher, Eisele, Ungemah, & Goodin, 2003). In HOT lanes, carpools and transit use the facility for free while other vehicles pay a toll to take advantage of the excess capacity.…”

Managed lane choices by carpools comprised of family members compared to non-family members

“…Whenever an HOV lane is established or the occupancy requirement increases, there is typically a time period when the volume to capacity ratio is low. Figure 2 represents the life cycle of an HOV facility that utilizes this extra capacity through the inclusion of lower occupancy vehicles that pay a toll (Swisher et al, 2003).…”