It's important to check the specifics of what is and is not covered by the Rental Vehicle Excess insurance component of travel insurance products (both complimentary credit card insurance and travel insurance purchased for a specific journey).
Commonly standard travel insurance will reimburse rental vehicle excess damage costs where the cause of damage is due to one of the damage causes included in the car rental company's standard excess.
For example, windscreen damage, under body and overhead damage are common causes of damage that are excluded from the standard rental excess by hire car companies. What this means is that if you hired a rental car and caused damage to the vehicle as a result of one of these excluded causes, it's likely that you will be liable to pay for the full repair cost without any compensation from your travel insurance policy. It's important to check the specifics of your chosen car rental company's inclusions and exclusions first to fully understand what is and is not covered under the standard excess.
Allianz Australia have created a specific insurance for the rental excess, Rental Vehicle Excess (RVE) Insurance, which provides cover for damage causes commonly excluded from the rental company's standard excess cover. It's a specialised product that provides cover up to your chosen premium if the car is either damaged or stolen while in your possession for items such as underbody, overhead, windscreen, tyres, single and multi vehicle accidents.
The car rental companies also offer their own Excess Reduction coverage products at the rental counter too. This is an additional fee you can pay to reduce your excess to a lower or nil value however it's important to check the terms of your selected product as excess reduction has multiple levels of coverage with varying damage inclusions and exclusions. Check the specifics of products sold by your preferred car rental supplier for further information.