Traffic Barrels or Sand Barrels
There can be confusion over what these are called, but the proper term is sand barrels, more generally they can be called traffic barrels. Those yellow barrels you to ensure that if your car goes off course it doesn’t end up in what the barrels are in front of. A lot of times they are in front of the concrete barrier that forms an exit off ramp.
These are not necessarily re directive, but they are still useful for protecting cars and trucks during a crash. Chances are if they are hit hard you are going to have to buy a new one, but most are designed so that a minor hit won’t damage them. Most barrels are able to be filled with sand, and can add up to around 1,000 pounds once filled.