At first you might think that this is a “no parking” sign. But the words below tell you that you cannot park on certain days. In this case there is no parking on even numbered days. If, for example, it is the 3rd, then you can park. The first word is “haam” which means “forbidden”. Next is “jot” which is “to park” and then finally “wan koo” which is “even numbered days”. The opposite is “wan kee”.
ห้าม จอด วันคู่ (haam jot wan koo)