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Status Report, Vol. 43, No. 8 | SPECIAL ISSUE: BOOSTER SEATS | October 1, 2008 Subscribe

First booster evaluationsNew ratings show which seats work best

When kids are too big for their child restraints, they need boosters to help them travel safely. But many boosters aren't up to the job because they don't make adult safety belts fit kids better. In fact, 13 of the 41 boosters the Institute evaluated with the University of Michigan Transportation Research Institute did such a poor job of this that they aren't recommended at all. Ten models are best bets and 5 are good bets. These evaluations are the first to tell U.S. consumers how well belt-positioning boosters improve belt fit for booster-age children in cars, minivans, and SUVs.

"We evaluated the safety belt fit boosters provide, not crash protection," says Institute president Adrian Lund. "This is because unlike child restraints, boosters don't restrain children in crashes. They simply position kids so lap and shoulder belts are in the right place to restrain them." Good boosters route belts across a child's bony parts, not soft parts like the abdomen, which is more vulnerable.

Two booster types — backless and highback — were assessed under conditions representing a range of 2001-06 model vehicles. Some highbacks convert to backless, and some boosters, called combination seats, can be used as child restraints. Highback and backless modes were evaluated separately because each mode affects how belts fit.

More importance was assigned to lap belt fit. All of the best-bet boosters locate this belt on the upper thighs. The main problem for the boosters that aren't recommended is they leave the lap belt on the abdomen. Fit is important because a correctly positioned lap belt loads pelvic bones during a crash, not the abdomen. A good booster also positions the shoulder belt at midshoulder, keeping the webbing away from the neck so it won't chafe and reducing the likelihood that kids will endanger themselves by putting the belt behind their back or under an arm.

"We'd expect the 10 best bets to improve belt fit for children in almost any car, minivan, or SUV," Lund says. "Likewise, it's clear that kids in the 13 boosters we don't recommend aren't getting the full benefit of improved lap belt fit. These boosters may increase restraint use by making children more comfortable, but they don't position belts for optimal protection."

Boosters the Institute does not recommend are the highback Compass B505, Compass B510, Cosco/Dorel Traveler, and Evenflo Big Kid Confidence; backless Safety Angel Ride Ryte; combination Cosco/Dorel Alpha Omega, Cosco/Dorel (Eddie Bauer) Summit, Cosco Highback Booster, Dorel/Safety 1st (Eddie Bauer) Prospect, Evenflo Chase Comfort Touch, Evenflo Generations, Graco CarGo Zephyr, and Safety 1st/Dorel Intera. At least 2 of these models have been discontinued, hopefully replaced by better designs. Booster makers sometimes reuse names and even model numbers for new seats, so manufacture dates and model numbers are important.

"Our data show it's possible to design a booster with good lap and shoulder belt fit," says Matt Reed, the study's lead author and research associate professor at the University of Michigan Transportation Research Institute. "Boosters that can't do that should be redesigned."

The 10 best-bet boosters are the most likely to position not only lap belts but also shoulder portions correctly on many children in many vehicles. Best bets include 3 backless seats: Combi Kobuk, Fisher-Price Safe Voyage, and Graco TurboBooster. These may require plastic clips to correctly position shoulder belts. Six highbacks are best bets: Britax Monarch, Britax Parkway, Fisher-Price Safe Voyage, LaRoche Bros. Teddy Bear, Recaro Young Style, and Volvo booster cushion.

Another best bet is the combination seat Safeguard Go when it's used as a backless booster. Combination seats convert to boosters by removing their built-in harnesses. At least 5 of the best-bet boosters have been discontinued but still are sold.

The 5 good bets provide acceptable belt fit in almost as many vehicle belt configurations. They are highbacks Combi Kobuk, Graco TurboBooster, and Safety Angel Ride Ryte, and combinations Recaro Young Sport and Safety 1st/Dorel Apex 65, when used as highbacks.

"Parents don't have to spend a lot of money for a booster that provides optimal fit," Lund points out. The Graco TurboBooster, for example, isn't the priciest. The highback version converts to a backless booster retailing for about $50, and the backless-only seat is about $20.

Child safety seat laws in 43 states and the District of Columbia include booster seat provisions, but until now there has been little information on how to pick one that provides proper belt fit. The government's dynamic tests don't measure what a booster is meant to do, which is to improve belt fit (see "New law directs NHTSA to develop standards for booster seats," Feb. 8, 2003).

Congress in 2002 told the National Highway Traffic Safety Administration to evaluate a belt fit test, but the agency decided to forgo testing. Instead, it only rates boosters by how easy they are to use (see "NHTSA won't rate child restraints for crash performance," Sept. 28, 2005). Manufacturers crash test boosters, but these simulated tests don't tell parents how boosters will fit kids in their cars.

Next step after child restraints

When children outgrow child restraints, parents may wonder if booster seats are necessary. They are, because safety belts are designed to fit adults, not young children. For most kids, belts usually don't fit properly until they're 4 feet, 9 inches tall. Boosters do what their name implies — elevate children so 3-point belts are positioned to provide effective restraint during a crash.

About 350 children ages 4-7 die in crashes each year in the United States. An additional 50,000 are injured. Because half of the fatally injured children in this age group ride unrestrained, the first step is to get them belted. Belt-positioning boosters can help by improving the fit, effectiveness, and comfort of adult belts.

There's convincing evidence that boosters, used with lap/shoulder belts, offer the safest way for kids to ride in vehicles once they outgrow child restraints, usually at age 4. Using boosters lowers injury risk by 59 percent compared with belts alone, a 2003 study by the Center for Injury Research and Prevention at the Children's Hospital of Philadelphia found. None of the 4-7 year-olds in boosters had any injuries to the abdomen, neck, spine, or back. Such injuries did occur among children using belts alone. A 2006 study by the same authors found that boosters reduce fatality risk among booster-age children by about 28 percent compared with belts alone.

Boosters don't work like child restraints. Rear-facing restraints for infants and forward-facing ones for toddlers and younger preschoolers are designed with built-in harnesses, sturdy structures, and foam padding to protect and restrain children in crashes. Boosters themselves don't restrain kids. A vehicle's safety belts do. Boosters position the belts so they'll work best. Some manufacturers claim their boosters provide extra protection in certain crashes like side impacts. Because there's no government or independent verification of these claims, parents are left to decide on their own if such features will help or are marketing gambits.

How they're evaluated

The booster evaluations begin with lap belt fit. Researchers positioned a Hybrid III crash test dummy representing a 6 year-old, the average size of a booster-age child, in a booster in a second-row seat from a car. They assessed lap/shoulder belt fit under 7 conditions spanning a range of belt positions in 31 vehicles.

Backless boosters generally provide better lap belt fit. Only 1 of the 15 backless boosters evaluated, the Graco TurboBooster used with a belt-positioning clip, provides optimal fit for both the lap and shoulder belts across all the belt configurations. On other backless boosters, the shoulder belt often falls too close to the neck or too far off the shoulder. When researchers evaluated the TurboBooster, they obtained the best shoulder belt fit when they used the clip the manufacturer provides for routing. Lund says parents with children in backless boosters should use the clips if needed to get good shoulder belt fit.

Because of built-in guides, highbacks generally do a better job of positioning shoulder belts in all vehicle configurations. However, 12 of the 26 evaluated fail to correctly position lap belts. Good boosters have belt-routing features that hold lap belts down and forward.

Combination seats and 3-in-1s

Six of the 12 highbacks in the not-recommended group are combination seats that can be used as forward-facing child restraints with 5-point harnesses, and 2 highbacks, the Cosco/Dorel Alpha Omega and Safety 1st/Dorel Intera, are 3-in-1 seats that can be used rear-facing for infants. The Intera also converts to a backless booster. The Safeguard Go, which converts to a backless booster but not a highback, is the only combination seat that's a best bet.

"Combination and 3-in-1 seats are marketed as the last child seat parents need to buy," Lund says, "but most of these seats aren't the best choice as boosters. Parents need to be careful. These seats should be fine when their harnesses restrain younger children, but many of these designs compromise the ability to provide children with good belt fit as booster seats."

Child, booster, vehicle affect belt fit

The evaluations reflect the fit of a lap/shoulder belt for an average size 6 year-old in many belt configurations. Some boosters might fit bigger or smaller children better in vehicles with different belt setups. And unlike dummies, kids fidget and slouch in their seats, so the real-world fit boosters provide will vary.

"No matter how a booster did in our evaluations, parents still need to see how it fits their child in their car," Lund advises. He urges them "not to rush to buy a new booster if theirs isn't among the top seats. Check how it fits and remember, it's better for kids to ride restrained in any booster than to let them ride unbuckled."

Since boosters frequently change, several newer ones weren't evaluated. The Institute plans to continue these assessments.

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