An additional driver surcharge is a daily fee imposed by car rental companies to cover the perceived increased insurance risk and administrative cost of having more than one person authorized to operate the vehicle. In 2026, this fee typically ranges from $10 to $15 per day, per driver, and is often capped at a maximum amount for the duration of the rental. The rationale behind the charge is that having multiple drivers increases the likelihood of an accident or wear and tear on the car. All additional drivers must be present at the rental counter with a valid driver's license to be officially added to the contract. It is important to note that many companies waive this fee for spouses or domestic partners, particularly if the primary renter is a member of the company's loyalty program (such as Hertz Gold or Avis Preferred). Some states, like California, have laws that strictly prohibit or limit these surcharges for spouses. Failing to register an additional driver is a major risk; if an unauthorized driver is involved in an accident, the rental insurance and any third-party coverage are usually voided, leaving the primary renter personally liable for all damages.