Corridor X Development Plan
This project applied analytical tools (regional economic forecasting models, GIS, transportation planning software, and traffic simulation software) to inform the planning and development process along an emerging interstate highway corridor. It illustrated the benefits of advanced planning and access management intended to preserve the functional integrity of the corridor and its interchanges and crossroads. The 96 mile study area includes all of Corridor X from the Mississippi State Line to US 31 in Birmingham and includes 28 interchanges with county, state and federal highways providing access to and from Corridor X.
Microsimulation of generalized access management and no access management alternatives along the interchange crossroads revealed that relatively simple access management treatments (nontraversable median, right- and left-turn bays) preserved higher operating speeds along the arterial roadway. A simplified analysis was conducted using the Access Management Impact Calculator (NCHRP 420) and that indicated safety benefits from the reduction of conflict points.
The report offers conceptual access management guidance on a number of interchange areas along the corridor and concludes with a discussion of state, county and city authority to implement various access management measures. An interesting example is that of the City of Decatur, Alabama on SR 67. Since the late 1980s, the City has implemented frontage roads by requiring developments to bond for their share of the future road. Direct highway access is provided with the understanding that the driveway will be closed and relocated onto the frontage road when it becomes available. The City decides at what time it will implement the frontage road and using the bond funds, it constructs the road and ties in to the existing driveways.
A strategy implemented based on a major street plan and combined with reserved right of way for long term intersection improvements appears to be a variation that can be justified, defended and implemented.
Jones, S., S. Ostaseski, M. Lewandowski, K. Sharma and M. Anderson, Corridor X Development Plan, University of Alabama, Birmingham, Regional Planning Commission of Greater Birmingham, University Transportation Center for Alabama (2006)