The Z4’s pre-crash front seatbelts will tighten automatically in the event the vehicle detects an impending crash, improving protection against injury significantly. The Emira doesn’t offer pre-crash pretensioners.
The BMW Z4 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 Emira doesn’t offer knee airbags.
The Z4 has standard City Collision Mitigation, which use forward mounted sensors to warn the driver of a possible collision ahead. If the driver doesn’t react and the system determines a collision is imminent, it automatically applies the brakes at full-force in order to reduce the force of the crash or avoid it altogether. The Emira doesn't offer collision warning or crash mitigation brakes.
The Z4 has standard Post-Crash Braking, which automatically apply the brakes in the event of a crash to help prevent secondary collisions and prevent further injuries. The Emira doesn’t offer a post collision braking system: in the event of a collision that triggers the airbags, more collisions are possible without the protection of airbags that may have already deployed.
Over 200 people are killed each year when backed over by motor vehicles. The Z4 (except Manual) offers an optional Active Park Distance Control that uses rear sensors to monitor for objects to the rear and automatically applies the brakes to prevent a collision. The Emira doesn’t offer backup collision prevention brakes.
The Z4’s optional 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 Emira doesn’t offer a lane departure warning system.
To help make backing out of a parking space safer, the Z4’s optional Cross Traffic Warning uses sensors in the rear to alert the driver to vehicles approaching from the side, helping the driver avoid collisions. The Emira doesn’t offer a rear cross-path warning system.
The Z4’s driver alert monitor detects an inattentive driver then sounds a warning and suggests a break. According to the NHTSA, drivers who fall asleep cause about 100,000 crashes and 1500 deaths a year. The Emira doesn’t offer a driver alert monitor.
The Z4 has standard BMW Assist, which uses a global positioning satellite (GPS) receiver and a cellular system to remotely unlock your doors if you lock your keys in, help track down your vehicle if it’s stolen or send emergency personnel to the scene if any airbags deploy. The Emira 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 Z4 and the Emira have standard driver and passenger frontal airbags, front side-impact airbags, front seatbelt pretensioners, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, available blind spot warning systems and rear parking sensors.