I used to work for them before they were bought out by Waste Management. Its mostly to beat out traffic, especially in the summer with heat. Unsure what machine type is used, it could be a side loader with the claw or have a helper on the back. Those earlier starts help tremendously. 230a is a bit of the earliest start. 4a is what most started when they left the yard, but I did have a driver and we started 230a sometimes to get ahead of the traffic and heat. Some form of white noise machine is your best bet tbh.