Method for adaptively controlling a vehicle speed (vFzg) in a vehicle, in particular a commercial vehicle, comprising a cruise control system, which method comprises at least the following steps: establishing a reference speed (vRef); controlling an engine and/or brakes and/or a transmission of the vehicle by the cruise control system depending on a vehicle target speed (vSoll) and/or on a vehicle target deceleration (zSoll) for fuel-efficient adaptation of the currently existing vehicle speed (vFzg) to the reference speed (vRef), the vehicle target speed (vSoll) and/or the vehicle target deceleration (zSoll) for a current driving-dynamic situation of the vehicle, defined by driving-dynamic vehicle parameters (vFzg, M, A, B, P), being determined depending on at least one calculation coefficient (W, X, Y, Z), the at least one calculation coefficient (W, X, Y, Z) being provided by an external computing unit outside the vehicle depending on the currently existing driving-dynamic vehicle parameters (vFzg, M, A, B, P) and depending on currently existing route information for a route portion ahead, the route portion ahead being established based on the currently existing driving-dynamic vehicle parameters (vFzg, M, A, B, P), characterized in that a currently existing position and a currently existing vehicle speed (vFzg) and a current vehicle mass and a maximum currently available drive torque and a maximum currently available braking torque are used as driving-dynamic vehicle parameters, the maximum currently available braking torque being weighted with a first calculation coefficient, the current vehicle mass with a second calculation coefficient, and the maximum currently available drive torque with a third calculation coefficient in order to calculate the vehicle target speed (vSoll) and/or the vehicle target deceleration (zSoll), and route information being taken into account via a fourth calculation factor, an algorithm on the external computing unit deriving the at least one calculation coefficient (W, X, Y, Z) depending on the currently existing route information and on a position of the vehicle, the algorithm for calculating the at least one calculation coefficient (W, X, Y, Z) only taking into account route information which lies in the route portion ahead, in order to restrict the amount of data to be processed by the algorithm. establishing a reference speed (vRef); controlling an engine and/or brakes and/or a transmission of the vehicle by the cruise control system depending on a vehicle target speed (vSoll) and/or on a vehicle target deceleration (zSoll) for fuel-efficient adaptation of the currently existing vehicle speed (vFzg) to the reference speed (vRef), the vehicle target speed (vSoll) and/or the vehicle target deceleration (zSoll) for a current driving-dynamic situation of the vehicle, defined by driving-dynamic vehicle parameters (vFzg, M, A, B, P), being determined depending on at least one calculation coefficient (W, X, Y, Z), the at least one calculation coefficient (W, X, Y, Z) being provided by an external computing unit outside the vehicle depending on the currently existing driving-dynamic vehicle parameters (vFzg, M, A, B, P) and depending on currently existing route information for a route portion ahead, the route portion ahead being established based on the currently existing driving-dynamic vehicle parameters (vFzg, M, A, B, P), characterized in that a currently existing position and a currently existing vehicle speed (vFzg) and a current vehicle mass and a maximum currently available drive torque and a maximum currently available braking torque are used as driving-dynamic vehicle parameters, the maximum currently available braking torque being weighted with a first calculation coefficient, the current vehicle mass with a second calculation coefficient, and the maximum currently available drive torque with a third calculation coefficient in order to calculate the vehicle target speed (vSoll) and/or the vehicle target deceleration (zSoll), and route information being taken into account via a fourth calculation factor, an algorithm on the external computing unit deriving the at least one calculation coefficient (W, X, Y, Z) depending on the currently existing route information and on a position of the vehicle, the algorithm for calculating the at least one calculation coefficient (W, X, Y, Z) only taking into account route information which lies in the route portion ahead, in order to restrict the amount of data to be processed by the algorithm.