Patent ID: 7266438

Claim:
A method of assisting a driver of a vehicle to negotiate a curved roadway, by identifying a true curve, determining an estimated negotiable speed for the true curve, and assisting the driver when an actual speed of the vehicle exceeds the estimated negotiable speed, the method comprising the steps of: (a) substantially automatically accessing an electronic map database, wherein the electronic map database represents a geometry of the roadway using a plurality of data points containing spatial information; (b) estimating a heading and a curvature magnitude of a particular portion of the roadway on which the vehicle is traveling using the spatial information of the plurality of data points, and identifying the true curve based on the heading or curvature and by comparing the curvature magnitude against a curve start threshold; (c) calculating the estimated negotiable speed for the identified true curve based at least on one or more characteristics of the curve; (d) determining the actual speed of the vehicle, comparing the actual speed and estimated negotiable speed, and autonomously generating a response when the actual speed of the vehicle exceeds the estimated negotiable speed.