The 2015 Toyota Prius C hybrid subcompact has now become a "IIHS Top Safety Pick" among new cars, according to the Insurance Institute for Highway Safety.

The crash-test ratings of the smallest Toyota hybrid improved after updates were made during the 2015 model year.

These changes allowed the Prius C to go from a "poor" to an "acceptable" rating in the latest IIHS small-overlap front crash test.

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That score improvement advanced the Toyota Prius C to the "Top Safety Pick" list.

The small-overlap test is meant to replicate a collision with the corner of a another vehicle, or a fixed object such as a utility pole or tree.

For the test, a rigid barrier strikes 25 percent of a car's front end, at 40 mph.

2015 Toyota Prius C IIHS small-overlap front crash test

2015 Toyota Prius C IIHS small-overlap front crash test

The changes made to improve performance in this area include "structural improvements to the front end and occupant compartment" on Prius C models--but only those built after May 2015, according to the IIHS.

The car's side-curtain airbags were also lengthened.

A car's ability to maintain the dimensions of its passenger compartment while absorbing an impact is crucial to preventing injuries, and analysts say the modified Prius C performed better in this regard.

Maximum intrusion was reduced by 3 inches in two areas of measurement, the IIHS said.

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However, not everything about the car's crash performance was considered ideal.

Seat belts and airbags did not adequately restrain crash-test dummies, although the newly-lengthened side-curtain airbags did a better job than the original versions, testers found.

The 2015 Prius C scored "good" ratings--the highest possible--in the other four IIHS crash tests.

Those include moderate-overlap front, side, head-restraint, and roof-strength tests.

2015 Toyota Prius C

2015 Toyota Prius C

Lack of the latest automated crash-prevention systems excludes the Prius C from a "Top Safety Pick+" rating.

The structural improvements made to the 2015 Prius C coincide with a minor refresh of the model.

Other changes include new styling and some added technology features, although the car remains mechanically unchanged.

MORE: 2015 Chevrolet Trax, Buick Encore Small SUVs Get IIHS Top Safety Pick Label

The IIHS introduced the small-overlap test in 2013, and has allowed vehicles with an "acceptable" rating to qualify as "Top Safety Picks" until now.

However, for the upcoming 2016 model year, vehicles will have to achieve a "good" rating on all IIHS tests.

That means that to maintain the "Top Safety Pick" status, Toyota would have to alter the Prius C further. Stay tuned.


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