Financing a new or used car could spell big financial trouble if your vehicle is ever declared a total loss – even if the accident is 100% the other driver's fault. Here's what you need to know about staying safe financially if you take out a car, truck, or SUV loan in the future.

Background - The 80% Rule

Many Americans believe if their vehicle is declared a total loss following an accident, insurance companies will provide enough money to cover the cost to replace the vehicle with a similar vehicle. The truth, though, is that insurance companies never provide you with enough money to buy a true replacement vehicle.

The rule of thumb to use when planning is 80%...if the true cost to get the exact same vehicle you were driving before an accident is $30,000, your insurance will only give you 80% of this dollar amount, or $24,000. You'll have to come up with the other 20%, or $6,000 in this example.

Why not 100%?

Unbeknownst to most of America, the valuation of vehicles deemed a total loss is determined by one company, CCC Intelligent Solutions. Per CCC, their services are used by most of the top 20 insurance companies. Instead of using a fair market valuation method to calculate the replacement cost of your vehicle, CCC uses a model that calculates a value that, when compared to valuation models found at Kelly Blue Book, Edmunds, and NADA, is systemically low.

How to Protect Yourself Financially

Here are some ideas to help you stay financially healthy when purchasing your next vehicle:

• Put down at least 20%. An unavoidable accident, even with no medical bills, could place your financial life in chaos. So try to have at least 20% equity in the vehicles you own from the moment you make the purchase or your loan will be underwater leaving you with no room to replace your vehicle with a similar make and model.

• Get a vehicle history report. Don't buy a vehicle that's been in an accident or has had other major issues such as flood damage. Buying a vehicle history report can help you identify cars, trucks, & SUVs that may create an even greater financial risk if you need to find a replacement.

• Build a fund for vehicle repairs and maintenance. Save up for inevitable maintenance and vehicle repairs. You could even use these funds to cover your 20% portion of a vehicle's replacement cost. Having enough money in this fund is critical. If you need to repair a car after a fender bender AND you do not have enough to cover your share of the cost, you will need to deal with the lender who has a lien on your vehicle. You can quickly find yourself in a financial trap.

• Choose shorter repayment terms. While the average car loan length is now well over five years for both new and used vehicles, choosing a shorter repayment term can help you build equity faster. You'll have a higher monthly payment, but you'll be in a better financial situation sooner in the event of an accident.