Where do I find guides for placarding hazardous materials on a truck?
There are a couple of resources that may be useful.
The NYS Department of Motor Vehicles (NYS DMV) has a Hazardous Materials Manual available online or at any DMV oiffice.
The familiar yellow Emergency Response Guidebook (ERG) is produced by the US Department of Transportation’s Pipeline and Hazardous Materials Safety Administration (PHMSA). The 2016 version being released in May.