Driver nearly sideswiped us at a light. Sped up to more than 20mph over the speed limit on a road where children were standing, waiting for their school bus. Then when we ended up beside him at a light and told him he nearly hit us, he flipped us off and started belligerently yelling. He sounded drunk or high on something. He proceeded to follow us erratically, nearly hitting us again, weaving across several lanes, ending up cutting in front of us and trying to brake check us even though we were keeping a safe distance, until he finally ended up stuck in traffic and we turned a different direction. This driver was completely out of his mind and seemingly under the influence.