Running the Penna Turnpike, we definitely have to be aware of the rules because the PA Turnpike Commission places their own restrictions on what you can or cannot take through the tunnels. In order to understand the Turnpike's rules, you need to understand some basic hazmat rules and definitions, like what bulk packaging means, etc... Unfortunately, some drivers still refuse to educate themselves even though they run the Turnpike.
So, we get all kinds of hazmat. I've pretty much pulled it all, bulk and non-bulk packaging, Table 1 and Table 2 materials. Bulk constitutes more than just anything over 119 gallons, you've also got the rule about the net weight of the container weighing 882 lbs or more. And yes, that rule about a container needing to be washed out is a real pain. It really sucks when you have to take a hazmat route that's over an hour out of route simply because of an empty tote with residue.
And don't forget about that nifty 8820 rule, where you have non-bulk packaging of hazmat with the same UN # that in total weighs 8,820 lbs or more, from the same shipper, with no other freight (hazmat or not) on the trailer. You need UN #s on the outside of that trailer, but it's still not considered 'bulk packaging.' You placard those trailers according to class and also have the UN #.