An RCA plug connector includes an annular outer ground sleeve, an insulating ring within the sleeve, and an elongated signal probe member having an exterior spring, including a plurality of circumferentially spaced bowed portions extending from within the insulating ring along the central axis. Probes include a conductive tube and a conductive plunger, contained in at least one end side of the tube, and having a distal end part protruding axially outward from the tube. If the rack-thrust-force deviation value is below the maximum-value-determination threshold value, the device refers to a preliminarily set map to determine a restoring speed at which the road-surface friction coefficient is to be restored to 1. Time differential is measured by autocorrelation of the entire impulse radio scan period, by detecting the leading edges of both incoming signals or various combinations of these methods. A memory is coupled to the processor and is configured to provide the processor with instructions.