Just merely obtaining a commercial driver's license, such as the Class A, should not on its own mean that your son's personal auto insurance rates will go up or down for that matter. If he needs to upgrade his auto insurance to a business or commercial auto insurance policy then his rates would normally rise since this type of policy would usually cost more due to what it covers and its limits.
With a CDL, insurance companies are aware that you should have professional training and are held to stricter regulations regarding your driving record so rates on your personal auto insurance should not be affected however there may be some insurers that say you will now drive more miles during the year and thus you are more at risk to be in an accident and thus your premiums will go up.
In general personal auto insurance premiums are not typically affected by a person obtaining a commercial driver's license.
If your son is getting commercial auto insurance though it may help lower his rates of this type of policy to have a CDL. Some insurance companies, such as Progressive, have an experienced commercial driver discount.
Progressive notes that you spend time and effort earning your Commercial Driver's License (CDL), which is why they reward dedicated drivers like this with their Experienced Commercial Driver discount. With this discount offer the longer your son has had his CDL the more of a discount he may receive.
With Progressive one can save as much as 15 percent on a commercial auto insurance policy for the experience they have as a CDL holder. Since you son is just recently received his Class A license this may not benefit him much now but should as he lengthens the time in which he maintains his CDL and if he needs a commercial auto insurance policy.
To see if his current personal auto insurance rates will be affected by him getting his Class A license your son should speak to his insurance agent about his insurance provider's rating system regarding those holding a CDL.
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