A method for determining a movement trajectory (MT) for a movable object (a vehicle) in a rule-based trajectory planning (TP) system, TP being performed based on minimizing overall costs of a cost function (CF), the CF considering violation costs (VC) which arise for each MT section from a potential respective violation of violatable rules as to the section, the rule violation (RV) including a state/transition RV, the state RV indicating a violation of a state rule indicating an impermissible state of the object; the transition RV indicating a violation of a transition rule indicating an impermissible state transition, the state RV being assigned a time-dependent cost amount of the VC, and the transition RV being assigned a fixed, time-independent cost amount of the VC, so that overall costs for a MT for each section violating a violatable rule depend on the time-dependent/fixed cost amount assigned to the violated rule.