Abstract: Vehicles driving on a roadway interrogate passive tags in or on lanes of the roadway. Codes in the tags represent locations along the highway and which lane the vehicle is traveling in. Units in the vehicles communicate longitudinal and lane positions derived from the codes among each other or with infrastructure units for purposes such as traffic management, alerts concerning other vehicles, alerts concerning external conditions, or traffic control. The units may also communicate vehicle lengths or other parameters or characteristics. Vehicle units may communicate with sensors and actuators in the vehicles for purposes such as updating the vehicles' positions between adjacent tags. Specific applications for intelligent transportation systems are described.

Abstract: A system comprises a mobile vehicle, a global positioning system (GPS) based vehicle position and heading system, at least one two-dimensional (2D) velocity sensor, a yaw rate system, and a vehicle position and heading estimator. The GPS based vehicle position and heading system is supported on the vehicle and measures global easting and global northing (measured position) of the vehicle, and determines a heading (measured heading) of the vehicle. The 2D velocity sensor measures the velocity of the vehicle with respect to the ground, over which the vehicle travels, in two orthogonal directions (measured velocity). The yaw rate system is supported on the vehicle and measures a yaw rate of the vehicle (yaw rate measurement). The vehicle position and heading estimator comprises at least one processor that computes a position of the vehicle (estimated position) and a heading of the vehicle (estimated heading) based on the measured position, the measured heading, the measured velocity and the yaw rate measurement.

Abstract: Vehicles driving on a roadway interrogate passive tags in or on lanes of the roadway. Codes in the tags represent locations along the highway and which lane the vehicle is traveling in. Units in the vehicles communicate longitudinal and lane positions derived from the codes among each other or with infrastructure units for purposes such as traffic management, alerts concerning other vehicles, alerts concerning external conditions, or traffic control. The units may also communicate vehicle lengths or other parameters or characteristics. Vehicle units may communicate with sensors and actuators in the vehicles for purposes such as updating the vehicles' positions between adjacent tags. Specific applications for intelligent transportation systems are described.

Abstract: An intersection assistance system includes at least one vehicle sensor and a gap estimator. The vehicle sensor is configured to obtain vehicle information on vehicles approaching the intersection along a main roadway. The gap estimator is configured to estimate gap information relating to a gap between the vehicles based on the vehicle information. The gap information includes a length of the gap, a location of the gap, and a velocity of the gap. In a method of obtaining information for use in assisting a driver of an entering vehicle to safely enter an intersection, vehicle information is obtained on vehicles traveling toward the intersection on a main roadway. Next, gap information is estimated relating to a gap between the vehicles based on the vehicle information. The gap information includes a length of the gap, a location of the gap, and a velocity of the gap.

Abstract: A geospatial database management system includes a geospatial database containing data elements that identify locations of a plurality of road features of a tangible road. The road features are displaced from each other in a widthwise direction that is transverse to the road.