I want to rent a car whilst driving in the States in September. My question is this: most travel insurance quotes do not specify whether it is ok to drive a car or not. I'll have CDW and SLI amongst others, these however do not cover injuries to myself should I have an accident. This is where Travel Insurance comes in.

How do I go about arranging this with my Travel Insurance company?

As long as you are simply using the car as a mode of transport then there is no need to arrange anything special with your travel insurers. You will have cover on travel insurance policies for medical treatment received as a result of an accident.

Some policies may exclude driving a vehicle under the Personal Accident section but this will be rare and only relates to a compensation payment if an accident results in the death of an insured person, loss of limb/sight or permanent total disablement. If such an exclusion is on the policy this would not affect the cover for any actual medical treatment.

Hope this helps, good luck.