A method is provided that performs a path search that identifies several path extensions. The method performs a viability check on a particular path extension by identifying first and second circuit geometries. The first circuit geometry is associated with a particular segment of a route that would result from the particular path expansion in a design layout. The second circuit geometry is associated with a circuit element to which the particular segment connects. The viability check also determines whether connecting the segment with the first geometry and the circuit element with the second geometry is allowable based on predetermined rules. The method stores the particular path expansion in a storage medium as a viable path expansion when the viability check determines that connecting the segment with the first geometry and the circuit element with the second geometry is allowable.