maps or printed maps is not as economical as simply stating locations as offsets, or ranges of offsets, along a linear feature. Linear referencing systems can also be made to be both very precise and very accurate at a much lower cost than is needed to collect latitude and longitude coordinates with high accuracy, especially when the goal is sub-meter accuracy. This is highly dependent upon the width of the linear feature, its centerline, and the visibility of the landmarks and markers that are used to define linear reference offsets. Often, roads are created by engineers using CAD tools that have no geospatial reference at all, and LRS is the preferred method of defining data for linear features. Limitations Consequently, a major limitation of linear referencing is that specifying points that are not on a linear feature is troublesome and error-prone, though not entirely impossible. Consider for example a ski lodge located 100 meters to the right of the road, traveling north. The linear referencing system can be extended by specifying a lateral offset, but the absolute location (i.e. coordinates) of the lodge cannot be determined unless coordinates are specified for the road; that process is prone to error particularly on curved roads. Another major drawback of linear referencing is that a modification in the alignment of a road (e.g. constructing a bypass around a town) changes the measurements that reference all downstream points. The system requires an extensive network of reference stations, and constant maintenance. In an era of mobile maps and GPS, this maintenance overhead for linear referencing systems challenges its long-term viability. (But see below for US Federal Highway Administration requirement that all State DOTs use LRS.) Nonetheless, travel along a road is a linear experience, and at the very least, linear referencing will continue to have a conversational role. Linear referencing systems are recognized by the US Federal government as a valuable tool for specifying right of way data, and are now actually required for the States. Therefore, it is not likely to see LRS usage decline any time soon. Applications ARNOLD: US Federal Requirements for Highways The US Federal Highway Administration is pushing states to move closer to standardization of LRS data with the ARNOLD requirement. To wit: "On August 7, 2012, FHWA announced that the HPMS is expanding the requirement for State Departments of Transportation (DOTs) to submit their LRS to include all public