A method of controlling event-responsive traffic lights (18 - 28) at an intersection of lanes (3 - 17) in a transportation network by means of a controller which switches the traffic lights (18 - 28) in cycles and, in each cycle, in a sequence (30 j) of phases (P n), each phase (P n) corresponding to a different switching state of the traffic lights (18 - 28) and allowing traffic flow on none, one or more of the lanes (3 - 17), wherein the controller has a memory storing a set of phase sequences (30 j) and is configured to change from one phase sequence (30 j) of the set to another phase sequence (30 j) of the set upon detection of a lane-related event, and by means of a central server connected to the controller and to one or more sensors (43 - 47) that measure traffic flows on the lanes (3 - 17), the method comprising, in the server: a) generating candidate sets (42 k) of phase sequences (30 j,k), wherein in each candidate set (42 k) all phase sequences (30 j,k) have a same number of time slots (S i,j,k) in the same order, each time slot (S i,j,k) is occupied by a respective phase (P n) and time slots (S i,j,k) of the same order have the same duration (T i), and wherein each candidate set (42 k) differs in at least one duration (T i) of a time slot (S i,j,k) of a specific order; b) determining the traffic flows on the lanes (3 - 17) by means of the one or more sensors (43 - 47); c) calculating a cost measure for each candidate set (42 k) on the basis of the determined traffic flows on the one hand and the durations (T i) on the other hand; and d) sending the candidate set (42 k,opt) with the lowest cost measure to the controller; in the controller, receiving and storing (40 c) the sent set (42 k,opt) in the memory as the set of phase sequences (30 j); and repeating steps b) - d) in successive intervals. a controller which switches the traffic lights (18 - 28) in cycles and, in each cycle, in a sequence (30 j) of phases (P n), each phase (P n) corresponding to a different switching state of the traffic lights (18 - 28) and allowing traffic flow on none, one or more of the lanes (3 - 17), wherein the controller has a memory storing a set of phase sequences (30 j) and is configured to change from one phase sequence (30 j) of the set to another phase sequence (30 j) of the set upon detection of a lane-related event, and by means of a central server connected to the controller and to one or more sensors (43 - 47) that measure traffic flows on the lanes (3 - 17), the method comprising, in the server: a) generating candidate sets (42 k) of phase sequences (30 j,k), wherein in each candidate set (42 k) all phase sequences (30 j,k) have a same number of time slots (S i,j,k) in the same order, each time slot (S i,j,k) is occupied by a respective phase (P n) and time slots (S i,j,k) of the same order have the same duration (T i), and wherein each candidate set (42 k) differs in at least one duration (T i) of a time slot (S i,j,k) of a specific order; b) determining the traffic flows on the lanes (3 - 17) by means of the one or more sensors (43 - 47); c) calculating a cost measure for each candidate set (42 k) on the basis of the determined traffic flows on the one hand and the durations (T i) on the other hand; and d) sending the candidate set (42 k,opt) with the lowest cost measure to the controller; a) generating candidate sets (42 k) of phase sequences (30 j,k), wherein in each candidate set (42 k) all phase sequences (30 j,k) have a same number of time slots (S i,j,k) in the same order, each time slot (S i,j,k) is occupied by a respective phase (P n) and time slots (S i,j,k) of the same order have the same duration (T i), and wherein each candidate set (42 k) differs in at least one duration (T i) of a time slot (S i,j,k) of a specific order; b) determining the traffic flows on the lanes (3 - 17) by means of the one or more sensors (43 - 47); c) calculating a cost measure for each candidate set (42 k) on the basis of the determined traffic flows on the one hand and the durations (T i) on the other hand; and d) sending the candidate set (42 k,opt) with the lowest cost measure to the controller; in the controller, receiving and storing (40 c) the sent set (42 k,opt) in the memory as the set of phase sequences (30 j); and repeating steps b) - d) in successive intervals.