All that said I do believe that those Deputy's running radar on 295, have at one time been through a Police Academy. I do not know if their certifications are current or not.
The Sheriff's Office does not need a written policy governing his/her Deputy's certification. As HOSS likes to point out you only need to look at the Code Of Virginia. The Code Of Virginia requires those that are certified Law Enforcement Officer's to attend recertification once every 2 years for 40 hours, to maintain their certification.
The Code Of Virginia also has requirements for certification to run radar. It also spells out the requirements to maintain that certification. The Code also has requirements regarding the equipment used to measure speed.
But you are probably correct that only about 85% of those that are written tickets on 295 do not go to court. Those that do go to court probably represent themselves and do not ask the right questions or know to ask for certain things that are required by the Code Of Virginia. It is not the Judges responsibility to assist in the defense of or the prosecution of a person.
Basically the Sheriff does not need a written policy governing certifications. The Commonwealth has already done it for him/her.
Maybe HOSS should read more of the Code that he likes to refer to, instead of just the section that tells him that he must uphold all the laws of the Commonwealth.