Keeping kids safe in the car means having them seated in a properly sized and properly-installed child safety seat. Lower anchors and tethers for children, commonly known as LATCH connectors, are supposed to ease the process by standardizing the anchors that car seats attach to. However, a new study suggests that LATCH connectors in many vehicles are more difficult to use than they should be.

The Insurance Institute for Highway Safety found that only 21 out of 98 of the top-selling 2010 to 2011 model year vehicles have LATCH connectors that are easy to use. IIHS teamed up with the University of Michigan Transportation Research Institute to evaluate how easy it is to use LATCH connectors in each car. Three factors were analyzed in the tests: how deep the anchors were in the seat, ease of access and the ability to install the child seats using less than 40 pounds of force.

“One problem the inspectors found is that buckles, plastic housing and vehicle seats interfere with the anchors,” writes the Detroit Free Press. “Those anchors sometimes are buried deep within the back seat, forcing parents to dig around in the cushions to find them.”

The LATCH connectors can be hard to reach, but many vehicles also lack them for the middle seat. The New York Times writes that, “only seven of the 98 vehicles, all 2010-11 models, had Latch anchors in the middle of the second-row seats — the safest place for children to travel, according to the study’s authors.”

If you’re in the market for a new family vehicle and you have young children, look for LATCH connectors that make child safety seat installation easy. IIHS reports that it was easiest to install child seats in the 2011 Audi A4 Quattro, Cadillac Escalade, Chevrolet Equinox LT, Silverado 1500, Suburban LT and Tahoe LS, Chrysler Town & Country, Dodge Caliber and Grand Caravan, Ram 1500 Crew Cab, Ford Escape XLT and F-150 SuperCrew Cab, GMC Sierra 1500 SLE, Honda Pilot EX-L, Kia Sedona, Land Rover Range Rover Sport, Mercedes C300 and E350, Mitsubishi Eclipse GS coupe and Lancer ES and Toyota Tacoma.

Models that failed the easy-installation test include the 2011 Buick Enclave CX, Chevrolet Impala LT, Dodge Avenger Express, Ford Flex SEL and Taurus Limited, Hyundai Sonata Limited and Toyota Sienna XLE.

You can also make sure that installing car seats will be easy by bringing them along on your test drive. The IIHS also lists some of the best and worst booster seats and child safety seats.

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