Patent ID: 8352173

Claim:
A method for hierarchically grouping principals to facilitate collision warning, the method comprising: obtaining, by a computing device, information on a number of non-primary principals; constructing one or more first-level groups of the non-primary principals based on a distance function, wherein constructing a respective first-level group of the one or more first-level groups involves placing a non-primary principal into the first-level group if the distance between this non-primary principal and any principal of the first-level group is less than or equal to a predetermined distance value; subdividing the first-level group into at least two second-level groups in accordance with the distance function based on both a velocity and a location of a non-primary principal within one of the second-level groups, wherein each second-level group comprises a non-overlapping subset of the non-primary principals in the first-level group; and responsive to predicting a collision between a primary principal in a host vehicle and the non-primary principals in at least one of the second-level groups, presenting a collision warning to the primary principal.