You may see traffic drums on the side of the highway, with blinking lights on top of them (barricade lights). They are typically orange and have reflective sheeting. There are also big yellow traffic drums that are used for cushioning potential impacts.
The yellow traffic drums are typically right next to exits and filled with sand. I am not positive as to what the proper term is for an orange versus a yellow traffic drum, but I believe the truth is there are many different terms, traffic barrels, channelizers etc.