The Honda Civic Si has standard driver and front passenger side knee airbags mounted low on the dashboard. These airbags helps prevent the driver and front passenger from sliding under their seatbelts or the main frontal airbags; this keeps them better positioned during a collision for maximum protection. Knee airbags also help keep the legs from striking the dashboard, preventing knee and leg injuries in the case of a serious frontal collision. The K4 doesn’t offer knee airbags.
Using vehicle speed sensors and seat sensors, smart airbags in the Civic Si deploy with different levels of force or don’t deploy at all to help better protect passengers of all sizes in different collisions. The Civic Si’s side airbags will shut off if a child is leaning against the door. The K4’s side airbags don’t have smart features and will always deploy full force.
The Civic Si’s lane departure warning system alerts a temporarily inattentive driver when the vehicle begins to leave its lane and gently nudges the vehicle back towards its lane. The K4 doesn’t offer a lane departure warning system.
The Civic Si has a standard blind spot warning system that uses sensors to alert the driver to objects in the vehicle’s blind spots where the side view mirrors don’t reveal them. A system to reveal vehicles in the K4’s blind spot costs extra.
To help make backing out of a parking space safer, the Civic Si has standard Rear Cross Traffic Monitor, helping the driver avoid collisions. Only the K4 LXS/EX/GT-Line offers Rear Cross-Traffic Collision Warning.
The Civic Si has standard HondaLink Assist, which uses a global positioning satellite (GPS) receiver and a cellular system to send emergency personnel to the scene if any airbags deploy. The K4 doesn’t offer a GPS response system, only a navigation computer with no live response for emergencies, so if you’re involved in an accident and you’re incapacitated help may not come as quickly.
Both the Civic Si and the K4 have standard driver and passenger frontal airbags, front and rear side-impact airbags, side-impact head airbags, front and rear seatbelt pretensioners, front wheel drive, height adjustable front shoulder belts, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, crash mitigating brakes, daytime running lights, rearview cameras and driver alert monitors.