Urban drivers often pick mini and microcars because they’re affordable, fuel efficient, and easy to park on city streets. Fender-benders are hazards of urban driving, and just one of them can add up to thousands of dollars in repair costs because car bumpers don’t adequately protect vehicles from damage. None of the bumpers on 7 mini and microcars the Insurance Institute for Highway Safety recently tested earn the top rating of good, and just 1, the Smart Fortwo, is acceptable. Five out of the 7 earn poor ratings and 1 earns a marginal. The Institute evaluated results according to a new ratings protocol for low-speed tests that better represents the damage insurance claims centers assess daily.

The worst performer is the Kia Rio, which sustained $9,380 total damage in the 4 tests — 2 full-width impacts and 2 corner — to earn a poor rating. The Rio’s repair bill is worse than those of most other small and midsize cars and minivans the Institute has tested. This minicar racked up about $3,700 damage, or 30 percent of its purchase price, in the full-front test alone. The Toyota Yaris, Honda Fit, Hyundai Accent, and Mini Cooper also earn poor ratings for bumper performance.

The Smart Fortwo is best overall, with $3,281 total damage in 4 tests. Costs are relatively low for this microcar because its pre-painted plastic body panels are dent-resistant, inexpensive, and easy to replace. The Chevrolet Aveo, a minicar, is next best, with $4,490 total damage.

These are the first bumper test results released under a new Institute ratings protocol that’s based on repair costs averaged and weighted to reflect real-world damage patterns. These averaged and weighted repair costs determine each vehicle’s overall rating of good, acceptable, marginal, or poor in 4 bumper tests representing full-width and corner crashes at low speeds.

Weighted average repairs must be less than $500 for a good rating, less than $1,000 for acceptable and less than $1,500 for marginal. Repairs of $1,500 or more earn bumpers a poor rating.

For more information: www.iihs.org