How to insure a rental car

The question at the rental counter is not whether the car is insured, but who pays if it is damaged, and in what order. Four sources can respond: the liability and physical damage coverage on your own auto policy, a benefit attached to the credit card that paid for the rental, the damage waiver and supplemental liability the rental company sells, and, for a business trip, an employer's commercial policy. Each has gaps the others fill, and each has conditions that are easy to break by accident, such as letting an unlisted driver take the wheel or crossing into Mexico from Arizona.

The decision takes ten minutes if you do it before the trip and thirty seconds of guessing if you do it at the counter. This guide sets out what to check on each source, the order in which they pay, the situations where the counter waiver is worth buying, and the ones where it is money spent on coverage you already own.

What to gather before you rent

Everything on this list is available from your desk before the reservation is made.

• Your auto declarations page, showing whether you carry collision and comprehensive, the deductibles, and your liability limits. Physical damage coverage on a rental usually mirrors the coverage on your own car; if you carry liability only, a rental is liability only too.
• The policy form's definition of a covered auto and the section on non-owned autos. Most personal policies extend to a car you rent for personal use in the United States and Canada, but not to Mexico, not to trucks over a stated size, and not to rentals longer than a set number of days.
• The guide to benefits for the card you will pay with, specifically the auto rental collision damage section. Note whether the benefit is primary or secondary, the maximum rental period, the excluded vehicle types, and the countries excluded.
• The rental company's terms, which set the waiver's price and its own exclusions: off-road driving, an unlisted driver, driving under the influence, and using the car for hire.
• Your destination and the roads you intend to use. Gravel roads to trailheads in Utah and Idaho, and a crossing into Sonora, both change the answer.

Step one: check what your own auto policy already does

Start with liability. A personal auto policy's liability coverage follows the named insured and resident relatives into a car they do not own, including a rental, at the limits on the declarations page. If you injure someone or damage their property while driving the rental, your own policy is the primary source in Arizona, Nevada, Utah and Idaho, and the rental company's minimum liability sits behind it. If your limits are low, the supplemental liability the counter sells is one way to raise them for the week; an umbrella policy you already own is another, and it usually follows you into a rental car as well.

Then physical damage. If your policy has collision and comprehensive, damage to the rental is covered the same way, with the same deductibles, subject to the policy's limits on vehicle type and rental period. What your policy often does not pay is what the rental company will bill you for beyond the repair: loss of use while the car is in the shop, administrative fees, and diminished value. Some carriers include loss of use for rentals; many do not, or cap it. That gap is the honest reason a person with full coverage might still buy the waiver. Call your carrier or your agent and ask three questions: does my collision extend to a rental, does it pay the rental company's loss of use, and does it cover a rental in the place I am going.

Utah's no-fault personal injury protection follows you into a rental; in the three at-fault states, your medical payments coverage does the same. Neither is a reason to buy anything at the counter, but knowing they apply saves you from buying personal accident insurance you already have.

Step two: check the credit card benefit

A rental car damage benefit on a credit card pays for damage to or theft of the rental car itself. It does not pay liability to anyone else; no card benefit does. It applies only when the rental is paid in full with that card, the reservation is in the cardholder's name, and the counter waiver is declined. If you accept the waiver, the card benefit goes away.

The distinction that matters is primary versus secondary. A primary benefit pays first, so your own auto policy is never involved, no claim appears on your record and no deductible applies. A secondary benefit pays only what your auto policy does not, typically the deductible and any loss of use the carrier refused, and it requires you to file with your own carrier first. If you have no auto policy at all, a secondary benefit often becomes primary by default, which is the situation of a city dweller who does not own a car.

Read the exclusions. Cards commonly exclude exotic and high-value cars, large vans and trucks, motorcycles, rentals over a stated number of consecutive days, and specific countries. Some exclude particular popular models. A benefit that would have covered a mid-size sedan may not cover the twelve-passenger van you rented for the family trip to Zion.

Step three: understand what the counter sells

The rental company offers three or four products, and the names vary. The damage waiver, sometimes called a loss damage waiver or collision damage waiver, is not insurance; it is the company agreeing not to hold you responsible for damage to its car, subject to its conditions. It has no deductible unless the counter offers a cheaper partial version, it covers the loss-of-use and administrative charges your own policy might not, and a claim under it never reaches your own carrier. Its price is quoted per day and adds up over a long rental.

Supplemental liability raises the liability protection available while you drive, above the company's own minimum. It is useful for someone with low limits on their own policy and no umbrella, and redundant for someone with high limits. Personal accident insurance pays medical costs for you and your passengers, which health insurance, medical payments coverage and Utah's personal injury protection already address. Personal effects coverage insures luggage in the car, which a home or renters policy already does, subject to its deductible.

The waiver is void if you break its conditions, and the conditions are strict: an unauthorised driver, driving off pavement, towing, driving outside permitted states or into Mexico, and reckless or impaired driving all cancel it. A waiver that does not apply is worse than no waiver, because you will have declined the card benefit to buy it.

Step four: decide, and put it in writing

Work through the cases in order. If you carry collision and comprehensive at home, your deductibles are moderate, and you have a card with a primary benefit, decline the waiver: the card pays the damage first and your own policy stands behind it. If you carry full coverage but your card benefit is secondary, decline the waiver only if you are willing to run a claim through your own carrier, pay the deductible and recover it from the card, and accept the small renewal effect; if you are not, buy the waiver. If you carry liability only, your own policy does nothing for the rental car; either the card benefit is your only source or the waiver is. If you have no auto policy, buy both the waiver and the supplemental liability, or rely on a non-owner policy bought in advance if you rent often.

Then check the destination. A rental crossing into Mexico needs a Mexican liability policy, sold by the rental company or a specialist; nothing on a domestic personal policy or card satisfies the Mexican requirement. Off-pavement driving on forest roads voids most waivers and many card benefits, so a trip that ends at a trailhead should rely on your own comprehensive and collision or should stay on pavement. A rental in another country needs the card's country list read carefully.

Whatever you decide, keep the record: the rental agreement showing the waiver accepted or declined, the card statement, and photographs of the car at pickup and return, all four sides and the interior, with the fuel and mileage. The photographs settle most disputes about pre-existing damage without anyone's insurance being involved.

Common mistakes

Each of these turns a ten-minute decision into a claim dispute.

• Assuming the card benefit covers liability. It never does.
• Accepting the waiver and then discovering it voided the card benefit you were counting on for the deductible.
• Letting a spouse or friend drive without adding them to the rental agreement, which cancels the waiver and can complicate the card benefit.
• Skipping the pickup photographs and being billed for a scrape that was already there.

A worked example

Suppose a couple from Boise fly to Las Vegas and rent a mid-size sedan for six days. At home they carry collision with a $500 deductible and liability limits they raised on the advice of their agent, and they pay with a card whose benefit is primary. They decline the waiver and the supplemental liability. On day four the car is sideswiped in a parking structure and the rental company bills $3,200 for the repair, $400 for loss of use and $100 in administrative fees. They file with the card benefit, which pays the whole $3,700 after receiving the rental agreement, the repair invoice and the police report number; their own carrier is never contacted and their deductible is untouched. Had their card benefit been secondary, the sequence would have been a collision claim with their own carrier for $2,700 after the deductible, and a card claim for the $500 deductible plus the $500 the carrier declined for loss of use and fees. Either way they are whole; the primary benefit made it one claim instead of two. The figures are illustrative.

How to use this

Before a trip, send us the card's benefit guide and we will tell you in a sentence how it fits with the auto policy we placed: whether the waiver is redundant, whether the rental period or vehicle is a problem, and whether the destination changes anything. For clients who rent often, the review sometimes shows that a rental car coverage endorsement or higher liability limits at home is cheaper across a year than waivers bought trip by trip, and sometimes it shows that what is in place already works and the counter can be declined with confidence. Either way the analysis costs nothing, in Arizona, Nevada, Utah or Idaho.