What's "barrel down" mean?

Native speaker’s answer
Rebecca
To "barrel down" means to move very quickly in a particular direction. Thus, "there's this truck barreling down the road" means that there was a truck that was driving very quickly down the road. Ex: The student barreled down the hallway, trying to make it to his class on time. Ex: The little girl saw a large dog barreling towards her and screamed in fear.