Hybrid cars are safer for their occupants but less so to pedestrians, those are the findings of a research conducted by the Highway Loss Data Institute (HLDI), an affiliate organization to the Insurance Institute for Highway Safety. On average, the odds of being injured in a crash travelling in a hybrid car are 25 percent lower than people in nonhybrid models. "Weight is a big factor," says Matt Moore, HLDI vice president and an author of the report.

"Hybrids on average are 10 percent heavier than their standard counterparts. This extra mass gives them an advantage in crashes that their conventional twins don't have." He notes that other factors, such as how, when, and by whom hybrids are driven, also may contribute. Researchers included controls to reduce the impact these differences may have had on the results. In another study researchers found that hybrid cars are 20% more likely to be involved in a pedestrian crash, due to the lack of noise coming from the engine when moving in electric-only mode.

"When hybrids operate in electric-only mode pedestrians can't hear them approaching," says Moore, "so they might step out into the roadway without checking first to see what's coming." Earlier this year Congress gave the agency three years to come up with a requirement for equipping hybrids and electric models with sounds to alert unsuspecting pedestrians.