Yes. You have missed the "W8" sign, that is warning you that in the breaking distance there will be a speed limit.
Number painted on it is telling you the speed. You should multiply it by 10 (e.g. 2 - 20km/h, 5 - 50km/h, 12 - 120km/h etc.). On this picture, this W8 is warning about the speed limit of 30km/h.
If there's no number painted on the sign, the speed limit is 20km/h.
If you want, you can also ask one of the trainers for a small training from basics in TD2.
~KMS