The disclosure relates to a computer-implemented method of expanding swarm data for controlling a motor vehicle by way of a driver assist system, wherein the swarm data for a route section include corresponding indicator swarm data regarding a course of at least two roadway or lane indicators on the route section, and wherein the swarm data are provided by registered roadway or lane indicator data. The method includes calculating, from the indicator swarm data, a minimum indicator swarm distance regarding the at least two roadway or lane indicators at one or more route section positions of the route section, and expanding the indicator swarm data regarding at least one of the at least two roadway or lane indicators with the indicator swarm distance at the one or more route section positions.