They're 20 ounces so nearly twice the size of an average drink. Even energy drinks which are typically bigger are usually 16 ounces (though sometimes 20). Looking at the website the highest-caffeine version has just under 160mg in 20oz.
Regardless, not sure what this has to do with the overall point, which is that you could consume multiple "high-caffeine" drinks and still be well under the amounts discussed in this study.
Regardless, not sure what this has to do with the overall point, which is that you could consume multiple "high-caffeine" drinks and still be well under the amounts discussed in this study.