Synthesis of State Practices in Developing Linear Referencing Systems
Greg Yarbrough, John Wisdom · 2009
Many departments of transportation (DOTs) have had legacy linear referencing systems (LRSs) in place since before the digital era. As geographic information system (GIS) technology has become widely used, the issue of how to implement and integrate LRSs into departmental work flows has presented a significant challenge to DOTs. The issues which contribute to these challenges include, but are not limited to, vendor implementations of linear referencing, legacy data issues, and staffing and budgetary constraints. The differences in resources available among the various DOTs have resulted in a variety of implementations of linear referencing with the GIS environment. As GIS has moved from the desktop to the enterprise environment, implementation issues have a greater impact on the ability to disseminate LRS-based data. In light of these differences, there is a need to evaluate the current state of GIS LRS implementations among the nation’s DOTs in order to take stock of what has been and is being done in order to share information and ideas. This report summarizes the results of the National Cooperative Highway Research Project (NCHRP) 08-36 Task 80, “Synthesis of State Practices in Developing Linear Referencing Systems.” The project consists of a survey of the nation’s DOTs regarding their LRS activities, as well as five case studies highlighting technical and institutional issues related to LRS implementation. The survey results showed notable variations in LRS implementations among DOTs. While all respondents are using linear referencing in some fashion, the level of implementation and integration with departmental business processes range from low to very high. Of particular interest is the relatively low implementation of multimodal LRSs. This suggests that most DOTs are still focusing on integrating and implementing roadway-based LRSs and have not been able to focus on other modes. It is expected that the information in this report will provide insight into the actual state of LRSs in the nation’s DOTs and expose some of the gaps between the theoretical possibilities and reality. In addition, the report should benefit states by highlighting some of the practices employed by DOTs with successful LRS implementations. This information could serve as a model for other states to follow in their LRS implementation efforts.