The Safest Explosion: The Science of Airbag Technology in Motorcycles

As motorcycles increase on the road, often as a fuel-efficient commuting choice, what is the best way to keep these riders safe?  While helmets and armored clothing protect many, the vast majority of motorcycles lack airbags, despite being a required safety feature in cars that save thousands of lives per year.  The Multistrada D-Air, a new integrated airbag system from Ducati and Dainese, aims to bring airbags to the motorcycle market in a new and innovative way.   But how do these systems work?

The history of airbags and motorcycles is a relatively short one; the first (and only until May 2014) commercially-available motorcycle with an airbag was the Honda Goldwing in 2006.  Frontal collisions account for 68% of crashes that cause injury and this airbag system aimed to reduce that number as well as severity of injuries resulting from crashes.  However, the Goldwing is only one model and a new 2015 Goldwing with airbags starts at $31,000, far exceeding the cost of the average new motorcycle.  Simultaneously, Dainese, a motorcycle gear manufacturer, developed prototypes and began researching the idea of an airbag incorporated with a motorcycle jacket.  In 2012, after years of testing in motorcycle racing, the Dainese D-Air Street was brought to the European market.  However, extensive additions of sensors and control units, not to mention cost (about $1500), showed Dainese more development was needed to effectively implement motorcycle airbag systems.  Thus, a partnership with Ducati (part of the Volkswagon group) was born.  The 2015 Ducati Multistrada is the first motorcycle capable of communicating with the Dainese D-Air wearable airbag system without additional sensors.  Sales started in Europe this summer, prompting attention with the release of a video (above) showing the integrated airbag system in action.

The original D-Air Street worked by incorporating lean sensors under the seat to sense falls, an ECU that mounted to the cockpit of the bike, and accelerometers on the front of the bike, all of which worked together to communicate with the wearable airbag.  These electrical sensors and wireless communication require battery charge to the vest and a SIM card to control the communication, much like the SIM card in a smart phone that allows wireless connections.  There is a continuous radio signal that connects the SIM card on the rider and the ECU mounted on the bike in order to eliminate interference.  This communication allows for airbag deployment in 45 milliseconds, as seen in the video.  The Multistrada D-Air system takes this integration one step further by eliminating any aftermarket installation needs and wirelessly integrating all the sensors within the bike.  This leads more thoroughly tested system electronics and continuous monitoring of the bike’s dynamics like acceleration or braking to let the airbag system know when to deploy.  Additionally, the Multistrada D-Air system has made airbag deployment even faster (20 ms) and safer with two airbag, while being capable of communicating with two sets of D-Air gear, making a passenger just as safe as the rider. Unlike the previous Honda airbag technology, all of these sensors work to deploy the airbag in a variety of situations (falls, slides, and collisions) instead of just frontal collisions.

In the event of a collision, the wireless communication between the bike’s sensors and the vest trigger the airbag to begin inflation.  This inflation is similar to that of a rocket booster in creating a controlled mini-explosion.  Much like a traditional vehicle airbag, nitrogen gases work to quickly inflate the airbag, creating a larger surface area to distribute force resulting from a collision.  However, where cars use a combination of sodium azide (NaN3), potassium nitrate (KNO3), and silicon oxide (SiO2) reactions to produce nitrogen gas, these motorcycle airbags possess a separate inflator that fills the airbag with nitrogen gas.  This small canister is housed within the vest system, allowing short travel time to inflate the airbags and space savings over traditional vehicle airbags.

Unfortunately, the new technology is only available in Europe (both the D-Air Street and Multistrada D-Air) and cost is still a limiting factor.  However, with other companies working on airbag systems and technology getting more advanced, significant progress is being made in rider safety, a definite positive for any motorcycle riders.

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