It's hazardous to use a hand-held cell phone while driving, so many people turn to hands-free models. But they're also dangerous say researchers at Israel's Assaf Harofe Medical Centre. They had 41 people sit in front of a bowl, stare at the center and hit a button when they saw a light twinkle. First they took the test without distractions. Then they did it while using a speaker phone--and, on average, missed twice as many lights, "Missing one point may be important while driving," says the study's author. "That could be a car braking." To be safe, park, then chat.