Yep. 6.2G/300K = 20.7K police officers. Somehow I think there are more than 20,667 police officers in the US.
Maybe they meant state highway patrols? The page on statistics brain says the source is "U.S. highway patrol" which is funny since last I checked the FBI has never issued a speeding ticket. Maybe park rangers issue tickets, but otherwise highway patrols are state entities. So, is the $6.2G only the total of tickets issued by state highway patrols? I haven't gotten a lot of tickets in my life (last one was 7 years ago) but more than once they were on local roads issued by local officers (you know, doing 50 in a 35mph zone). So, I'm really uncertain as to the accuracy of any of their numbers.
That aside, who cares? Not every state/local govt is Hampton, FL. http://www.cnn.com/2014/03/09/...
Speaking of math, U.S. state governments combined spend about $1.5T a year. (http://www.usgovernmentspending.com/) So $6.2G is less than 1% of just the state budgets. Not a big deal.
Anyway, more information = more ways to tax. Think of an autonomous car as a black box that not just records your driving but does your driving. http://www.abqjournal.com/3311... But in this case we really don't even need the black box. Simply raising the gas tax a few cents would easily make up the lost revenue. State and local fuel taxes were over $40B in 2011 (http://www.taxpolicycenter.org/taxfacts/displayafact.cfm?Docid=401). Fed fuel tax revenue was over $25B in 2006 (wikipedia). So, ask yourself, would you mind paying a few cents more per gallon if it meant NEVER HAVING TO PAY A SPEEDING TICKET AGAIN?
All in all, a tempest in an, ahem, teapot.