Map accuracy and location expression in transportation – reality and prospects

We were contracted to test a suite of proposed location messaging standards for the intelligent transportation systems (ITS) industry. We studied six different databases for the County of Santa Barbara, documented types and magnitudes of error, and examined the likely success of the proposed standards. This paper synthesizes the test results and identifies caveats for the user community as well as challenges to academia. We conclude that, first, current messaging proposals are inadequate, and superior methods are required to convey both location and a measure of confidence to the recipient. Second, there is a need to develop methods to correct map data geometrically, so that location is more accurately captured, stored and communicated, particularly in mission critical applications such as emergency servicing. To address this, we have developed methods for comparing maps and adjusting them in real time. Third, there must be standards for centerline map accuracy, that reflect the data models and functions associated with transportation.