An arrangement of a traffic infrastructure and an optic sensor system (10, 20), the traffic infrastructure having a traffic carrying surface to support conveyance elements of a vehicle, therewith allowing movements of the vehicle over the traffic carrying surface, the optic sensor system (10, 20) comprising an interrogator and at least one fiber optic sensor that is coupled to said interrogator and that is arranged below said traffic carrying surface, the at least one fiber optic sensor comprising an optic fiber with a plurality of optic strain-sensor elements distributed over its length, which plurality of optic strain-sensor elements have mutually different optical characteristics, the interrogator being configured to transmit an optical interrogation signal into the at least one fiber optic sensor, to receive a response optical signal that has been modulated by said fiber optic sensor based on its optical characteristics, and to identify changes in the optical characteristics of the response optical signal resulting from strains induced in said optic strain-sensor elements as a result of a conveyance element of a vehicle moving over the traffic carrying surface across said at least one fiber optic sensor, wherein the at least one fiber optic sensor extends at least substantially according to a straight line in a direction at least substantially parallel to the traffic carrying surface, characterized in that the at least one fiber optic sensor is provided with at least one anchor element that extends around the at least one fiber optic sensor between mutually subsequent optic strain-sensor elements, the at least one anchor element having a circumference in a plane transverse to a longitudinal direction of the at least one fiber optic sensor that is at least 1.5 times larger than a circumference of the fiber optic sensor in a plane transverse to said longitudinal direction at a position of an optic strain-sensor element. the optic sensor system (10, 20) comprising an interrogator and at least one fiber optic sensor that is coupled to said interrogator and that is arranged below said traffic carrying surface, the at least one fiber optic sensor comprising an optic fiber with a plurality of optic strain-sensor elements distributed over its length, which plurality of optic strain-sensor elements have mutually different optical characteristics, the interrogator being configured to transmit an optical interrogation signal into the at least one fiber optic sensor, to receive a response optical signal that has been modulated by said fiber optic sensor based on its optical characteristics, and to identify changes in the optical characteristics of the response optical signal resulting from strains induced in said optic strain-sensor elements as a result of a conveyance element of a vehicle moving over the traffic carrying surface across said at least one fiber optic sensor, wherein the at least one fiber optic sensor extends at least substantially according to a straight line in a direction at least substantially parallel to the traffic carrying surface, characterized in that the at least one fiber optic sensor is provided with at least one anchor element that extends around the at least one fiber optic sensor between mutually subsequent optic strain-sensor elements, the at least one anchor element having a circumference in a plane transverse to a longitudinal direction of the at least one fiber optic sensor that is at least 1.5 times larger than a circumference of the fiber optic sensor in a plane transverse to said longitudinal direction at a position of an optic strain-sensor element.