The average light vehicle on the road today was manufactured in 2003 or 2004. While cars built today usually meet the highest of safety standards, there are a number of vehicles built more than a decade ago that are relatively unsafe.

To determine the most dangerous cars in America, 24/7 Wall St. reviewed crashworthiness evaluation results from the Insurance Institute for Highway Safety, a nonprofit research organization funded by auto insurers. The IIHS conducts a number of crash tests to determine how well a vehicle minimizes the possibility of injury for its occupants in a collision. While the IIHS has added several tests since, in the early 2000s, the nonprofit primarily tested frontal collision, broadside collision, roof strength, and head restraint and seat safety.

To compile America’s most dangerous cars, the model must have received a poor or “marginal” rating in either the frontal crash impact or side crash impact safety tests — frontal and side impact collisions are the most fatal. Additionally, a car must have also received a “poor” rating on either the roof strength test, which simulates a vehicle rollover, or the head restraint and seat test, which simulates a rear-end collision. As we are only looking for vehicles that are still likely driven on the roads today, we only reviewed generations of cars which included the 2005 model year or later.

Click here to see the 12 most dangerous cars.

The safest cars tend to be the largest. In a frontal car collision, the heavier the oncoming car is and the shorter the distance between the occupant and the front of the car, the higher likelihood of injury. Smaller, lighter cars carry a greater risk of injury, as occupants will experience greater force in a collision. In 2014, there were 55 driver deaths in subcompact cars per million registered vehicles, a far higher driver death rate than the 19 fatalities in very large cars per million registered vehicles.

Safety is an important consideration when buying a car for many Americans. Of the top 10 best selling cars today, eight are top-safety IIHS picks. For many of the cars on this list, low safety ratings may have hurt their popularity among U.S. consumers and ultimately led to their discontinuation. Of the 13 most dangerous cars, five have been discontinued in the United States at some point.

The roads are much safer today than they were a decade ago. Passenger vehicle deaths fell from 21,952 in 2004 to 15,479 in 2014. This statistic is even more impressive when considering that there are many more drivers today. Over that same 10-year period, driver deaths fell from 117 per million registered vehicles to just 44.

While improvements in road infrastructure likely partially contributed to this increased safety, the reduction in fatalities was largely driven by manufacturers building safer cars, according to the IIHS.

The overall improvement auto industry safety is apparent when considering that most of the cars on this list are about a decade old. The vast majority were sold in the 2005 or 2006 model years. The most recently produced generation of car on this list is the 2006-2009 Kia Rio.

In the mid-2000s, the Hyundai Accent, Kia Rio, Nissan Sentra, and others failed at least two of the four major tests conducted the IIHS. The 2016 models of each of these cars received “good” or “acceptable” ratings in all four categories. The Sentra rated as one of the IIHS’s top safety picks.

Click here to read our methodology.

These are the most dangerous cars in America.