A method for safety improvement when a motor vehicle (100) having a power train with an engine (230), automatic gearbox (240) and torque converter (237) is stationary and particle filter (320) for the exhaust gases of the engine (230) is being regenerated; The step of applying safety brake action to keep the vehicle (100) stationary despite torque transfer being maintained in the power train. The step of choosing in the gearbox (240) a gear step which is higher than an initial gear step of the gearbox (240) in order to reduce the torque transferred to the vehicle's tractive wheels (247a, 247b) when the vehicle is thus kept stationary. Also a computer programme product with program code (P) for a computer (200; 210) for implementing the method. Also a device for safety improvement when a motor vehicle (100) is stationary and a particle filter (320) for the exhaust gases of the engine (230) is being regenerated. Also, a motor vehicle (100) equipped with the device.