The Honda Civic is still the only small car to get the top rating on a new test that simulates a severe front-end crash, the Insurance Institute for Highway Safety says.

IIHS, which is funded by insurance companies, today released another batch of test results for its "small overlap" crash test, which replicates an accident in which the front corner of a car clips another car, a pole or a tree at 40 mph.

The group gave "acceptable" ratings to the Dodge Dart, Ford Focus, Hyundai Elantra and 2014 Scion tC, which was enough to earn them Top Safety Pick+ honors.

However, they did not do as well as the two- and four-door Civic, which received "good" ratings earlier this year -- a payoff for Honda engineers in Ohio after they redid the car's front-end architecture to better handle this type of crash.

Automakers generally make greater use of high-strength or hot-formed steel to help cars stand up to small-overlap crashes. The engineering challenge can be daunting because these crashes tend to bypass the structures under the hood that are designed to crumple and absorb the force of a straight-on front-end crash.

Many popular and entry-level small cars struggled with the new test. The Nissan Sentra, Kia Soul and 2014 Kia Forte all received a "poor" rating today while the Chevrolet Cruze, Chevrolet Sonic and Volkswagen Beetle received "marginal" ratings.

"In the worst cases, safety cages collapsed, driver airbags moved sideways with unstable steering columns and the dummy's head hit the instrument panel," IIHS Chief Research Officer David Zuby said in a statement. "Side curtain airbags didn't deploy or didn't provide enough forward coverage to make a difference. All of this adds up to marginal or poor protection in a small-overlap crash."

Starting for model year 2013, the IIHS made an "acceptable" or "good" score on the small-overlap test a prerequisite for Top Safety Pick+ honors, though cars that flunk the test are still eligible for Top Safety Pick plaudits.

The passing grade for the Scion tC coupe is a sign of improvement for Toyota, which drew criticism from IIHS over the past year as top-selling models such as the Camry sedan and RAV4 crossover received low marks on the new test.

IIHS didn't test the 2013 Corolla sedan because it is on the verge of a redesign.

Joe Nolan, the head of the group's testing laboratory, said during a recent interview that Toyota has asked IIHS to test the redesigned 2014 Corolla, Highlander SUV and Prius compact hybrid, as well as the freshened 2014 Camry. He said it was a sign of the automaker's confidence in its efforts to steel those cars against small-overlap crashes.