"Front crash prevention systems can add a thousand dollars or more to the cost of a new car," said David Zuby, IIHS chief research officer, in a release. "Our new ratings let consumers know which systems offer the most promise for the extra expense."

Front crash prevention systems are rated superior (highest rating), advanced, or basic (lowest rating) depending on features and effectiveness. Vehicles with front crash prevention systems are tested at 12 mph and 25 mph. In order to earn a superior rating, vehicles with optional or standard front crash prevention systems with an autobrake feature must avoid a crash or substantially reduce speeds in both tests.

An advanced rating is given to systems with an autobrake feature that can avoid a crash or reduce speeds by at least 5 mph in at least one of the tests. Front crash prevention systems that meet National Highway Safety Administration (NHTSA) performance criteria earn a basic rating. Those systems must issue a driver warning in five out of seven tests in three different scenarios.

The first models to be tested by the IIHS include 2013 and 2014 model year moderately priced and premium midsize cars and SUV/crossovers. Of the 74 vehicles tested, seven earned a superior rating, six models earned an advanced rating, and 25 models earned a basic rating, while the remaining 36 models didn't offer a front crash prevention system or didn't meet IIHS or NHTSA standards.

IIHS Superior-Rated Vehicles

Vehicles earning a superior rating include the Subaru Legacy sedan and Outback crossover, Cadillac ATS sedan and SRX crossover, Mercedes-Benz C-Class, as well as the Volvo S60 sedan and XC60 crossover. When not equipped with the available autobrake feature, the 2014 Acura MDX (rated advanced) and the Cadillac ATS sedan and SRX crossover earned a basic rating with their available front crash prevention systems.

IIHS Advanced-Rated Vehicles

An advanced rating was given to the 2014 Acura MDX, Audi A4 sedan and Q5 crossover, 2014 Jeep Grand Cherokee, Lexus ES sedan, and Mazda6. While Volvo S60 sedan and XC60 crossover models equipped with the available front crash prevention system earned a superior rating, models only equipped with the standard City Safety autobrake feature earned an advanced rating. Volvo's City Safety feature slows the vehicle to avoid a collision without warning the driver.

IIHS Basic-Rated Vehicles

A basic rating was given to the BMW 3 Series and X3; Chevrolet Equinox and Malibu; 2014 Dodge Durango; Ford Edge, Explorer, Flex, and Fusion; GMC Terrain; Honda Accord and Crosstour; 2013 Infiniti EX, FX, JX; 2014 Infiniti Q50, QX50, QX60, and QX70 models; 2014 Jeep Cherokee; 2014 Lexus IS sedan and RX crossover; Lincoln MKT, MKX, and MKZ; and Mercedes-Benz GLK-Class and M-Class.

The Subaru EyeSight system performed the best with the Cadillac's Automation Collision Preparation system second best in testing, according to the IIHS. Subaru's system helped the Legacy and Outback avoid a collision at both test speeds, while Cadillac's system helped the ATS sedan and SRX crossover from hitting the object at 12 mph and reduced speed by 15 mph and 19 mph in the 25 mph test for the ATS and SRX, respectively.

The BMW 3 Series and Infiniti JX (QX60) earned a basic rating for only minimal braking in both tests. The Toyota Prius v wagon with an autobrake feature didn't perform well enough to earn an IIHS rating.

The IIHS' 2014 Top Safety Pick+ winnerswill be required to have a basic, advanced, or superior front crash prevention rating on top of the existing crash-test rating requirements.

Source: IIHS