You're over thinking it - assuming you rented from Hertz.co.uk then all the mandatory insurance is covered in the rental.
"Hertz do cover third party liability in the 'Liability Insurance Supplement'. Is that correct, " - Yes this is the part of the insurance that covers you if you are sued by another driver or damage property etc.
"is there anything I need to check with Hertz i.e. excesses etc and how much is covered?" - The Loss Damage Waiver covers the vehicle and might include an excess but it should be clearly stated. The excess for a car is normally low but I think you can reduce it to zero, if there is any excess, if you buy further insurance from Hertz but I never bother.
"'Personal Accident Insurance / Personal Effects Coverage' for approx $7 USD per day but I think my travel insurance policy covers me in case of an accident?" - This will probably be covered by your travel insurance but as travel policies vary wildly I cannot confirm this.
You have all the insurances that I would want for a rental car in the US so I wouldn't worry but be aware that some rental firms will try to sell you further insurance when you pick up the car, most of them are unnecessary and I've never had this issue with Hertz as it's normally hand over your reservation confirmation, driving licence etc and you're quickly on the road. Have a great trip.
Those "fee recovery" add-ons are mandatory. Everyone pays them. You'll need liability insurance and the damage waiver. The latter will cover any damage to the vehicle that you or another person inflicts, while the liability covers damage you inflect on other people or property. Your travel insurance should cover your medical expenses, which will not be covered by these Hertz options.
As long as, as already said, you rent a car, before travel to the US, and from a .co.uk website for a specific US rental company, or use a third party consolidator who has quoted you in anything other than US$, then normally the very necessarily insurances that you'd need to drive in the USA with adequate cover should be included.
I don't have time here to go into a long spiel, so please may I suggest that, if you want more info on the whole can of worms that car rental abroad can be, you have read of this topic. I accept it's not the best source of the specific info you seek, but buried in the detail is a lot of chat about car insurance types, and what you should have:
tripadvisor.com/ShowTopic-g1-i12567-k4713887…
When you pick up the car from Hertz, do check what you sign and don't agree to pay again for any insurance that was already included in your quote. As many of the reps at the desk are so used to US based customers, they often automatically get to to buy extra insurance (for which they get commission, hence the keenness to do this). If you sign up before travel to Hertz No.1 Club on the Hertz website and get your booking linked to the membership number, it might smooth your path when you pick up the car.
LDW (included by Hertz) - This is to cover damage to the vehicle, but we may still be liable for an excess if damage does occur, even if it's not our fault? Am I right in thinking that 'car rental insurance' is designed to pay this excess?
Liability Insurance Supplment (included by Hertz) - This covers third party liability claims should I injure someone or damage another vehicle/property? I assume that this is a minimum amount set by the government in these States, is the minimum usually enough?
Personal Accident Insurance (not included by Hertz, but advertised for $7 per day extra) - This covers medical expenses for myself, and should be negated by the fact that I have travel insurance which pays medical costs?
I was mainly confused about the difference between terms, and I wasn't sure if 'car rental insurance' that you could purchase online was designed to cover third party liability/accidents or whether it was simply to cover any excesses payable should damage occur. I think the thing I'm worried about most is injuring someone and being sued for a sum that I'll be paying off for the rest of my life!
I just did a dummy booking on the Hertz UK website and this was what I found
"LDW (included by Hertz) - This is to cover damage to the vehicle, but we may still be liable for an excess if damage does occur, even if it's not our fault? Am I right in thinking that 'car rental insurance' is designed to pay this excess?" - There shouldn't be any excess and the full value of the rental value is covered so you don't need any further insurance.
"Liability Insurance Supplment (included by Hertz) - This covers third party liability claims should I injure someone or damage another vehicle/property? I assume that this is a minimum amount set by the government in these States, is the minimum usually enough?" - Think of this as the UK version of 3rd party insurance in the unlikely event you have an accident and are sued - the minimum is adequate.
"Personal Accident Insurance (not included by Hertz, but advertised for $7 per day extra) - This covers medical expenses for myself, and should be negated by the fact that I have travel insurance which pays medical costs?" - Very unlikely to be needed as any medical costs will be covered by your travel insurance, subject to the terms and conditions of your policy.
In case you didn't know dont drive on unpaved roads as this will invalidate your insurance coverage.
There is no easy answer.. Most additional SLI limits the cover to $1,000,000 unlike unlimited liability in the UK. As far as I can tell there is no unlimited liability available and even private car insurance is usually limited.to a specific amount. damages greater than £1000,000 are not uncommon in the UK for a wage earner with family who is killed or damaged and is unable to work again let alone care.
This is a really useful thread. I have 2 questions about car rental in the U.S:
1. Is there any difference in making the reservation via a .co.uk site rather than .com?
2. Looking at a couple of rental places in Vegas some bundle up the insurances etc. Into gold/silver/bronze type packages. At least 1 of these had 24 hour breakdown cover in the silver package but not the bronze - as it's their car surely they would help recover it whether I brought that package or not?