The redesigned seat-mounted side airbags deploy lower in the pelvis area and incorporate new venting technology. The tunnel vent on the seat mounted side airbag is lined up with the shoulder area of the occupant. On larger passengers, the shoulder engages the vent and keeps it from venting so the gas stays inside the airbag. On smaller passengers, the effect is just the opposite: Because the occupant's shoulder is below the vent, the gas vents out of the airbag.The driver's airbag uses a reconfigured curve-shaped tether system that pulls in the lower section to create a pocket that is designed to help lessen the impact of the airbag on the driver's chest and ribs in frontal crashes. Deploying at the same time is a driver's knee airbag. Top fuel economy, driver assist technologyThe Fusion boasts leading fuel economy and numerous technologies that help enhance the driving experience, reduce stress and assist in avoiding potentially harmful scenarios. Fusion brings the broadest selection of fuel-efficient powertrains in the midsize car segment. Consumers have the choice of a pair of EcoBoost four-cylinder engines, a normally aspirated four-cylinder engine, an automatic start stop system to shut off the engine at stationary idle, front-wheel drive and all-wheel drive applications, and a choice between automatic and manually shifted six-speed transmissions. The Fusion also offers hybrid and plug-in hybrid alternatives, which offer 47 mpg on the highway and in the city (hybrid) and 100 mpgE, a mile per gallon equivalency metric for electrified vehicles. Maneuvering parking lots and traveling open roadways become even safer and less stressful with Fusion's available sensor-based BLIS ® (Blind Spot Information System) with cross-traffic alert. BLIS sounds an alert when a vehicle is detected entering a blind spot. Cross-traffic alert warns if traffic is detected approaching from the sides, such as when Fusion is leaving a parking space in reverse. Parallel parking the Fusion is also virtually stress-free with the available active park assist. With the press of a button, the system detects an available parallel parking space and automatically steers the vehicle into the space. Drivers remain in control of gear selection, acceleration and braking.