The Toyota Tundra earned a "poor" grade from an American highway safety regulator, causing the consumer recommendation rating for the pickup truck to drop.

In its latest round of crash tests, the Insurance Institute for Highway Safety (IIHS) gave the Toyota pickup the lowest possible rating out of the 11 mid-size and full-size trucks it reviewed.

Safety Of Pickup Trucks

To test the highway safety of pickups, the IIHS put four compacts and seven full-sized trucks through a crash test that simulates when a vehicle's front corner hits a stationary object or another car. The relatively new test involved having the vehicles run at 40 mph.

Of all the pickup trucks that were tested, Nissan Titan, the Ram 1500 and the Ford F-150 each received a "good" rating, while the Honda Ridgeline had an "acceptable" grade from the IIHS.

The GMC Sierra and the Chevy Silverado 1500 were both given "marginal" rating for its passenger protection following the crash tests.

Dan Flores, a representative for General Motors (GM) reaffirms the American automaker's commitment to improve the safety of its vehicles. He said GM designs its cars to keep passengers safe from a broad range of collisions such as front, offset, angle, side and rear impacts.

Meanwhile, a Toyota spokesperson told CNBC that the company's main priority is the safety and reliability of its cars.

"We'll continue to look for ways to improve in an effort to exceed customers' expectations — particularly in new testing such as IIHS' passenger-side front small overlap (tests) for pickup trucks," the spokesperson said.

The IIHS said that pickup trucks generally have a problem with keeping their passengers safe from front-end collisions. This could be caused by a lack of emphasis on front-seat passenger protection found in older pickup designs.

The regulator believes that if these vehicles were to be redesigned, they will likely include better protection for passengers sitting at front.

The new IIHS crash test is expected to impact how consumers buy pickup trucks.

Consumer Reports Rating

The Toyota Tundra's poor performance at the IIHS testings has caused its Consumer Reports (CR) score to drop below the recommendation threshold.

On the other hand, the Ford F-150 is the only full-size pickup that received the consumer website's approval.

Jennifer Stockburger from CR's Auto Test Center explains the importance of getting high marks in such vehicle tests.

"Pickup trucks are becoming increasingly popular for hauling families as well as cargo," Stockburger said. "That means assessments like this one — that look at passenger safety as well as driver safety — are just as important for pickups as they are for cars and SUVs."

CR scores are used to determine whether a vehicle is fit for consumer use. It factors in the results of various crash tests conducted by the National Highway Traffic Safety Administration and the IIHS for its overall grading.

CR also considers the vehicles' safety systems, their road-test scores, and the results of website's exclusive Auto Surveys, where car owners are asked about how satisfied they are with the car they bought.

Vehicles that notch high CR Overall Scores are given a solid recommendation by Consumer Reports.