Email is a word that refers to both the system (defined by several RFCs, including the SMTP spec) and an individual message (an email). You pluralize them differently.
I checked my email today. (Refers to the system itself, like I checked the mail.)
I sent you two emails today. (Refers to individual messages, like I sent you two letters.)
So if you’re talking about specific, countable messages, the plural is emails.
Also, neither “traffic” nor “traffics” appear anywhere on the page, so I’m not sure what you’re referencing. Maybe you meant that as an example of a word like email as in the system of email.