The fourth-generation Mazda MX-5 uses ultra-high-tensile steel as well as aluminum construction in the body structure. I could not locate a table to explain the different materials used on the images below. I safe assumption would the blue colored sections are stronger steels. Also keep in made that the A-pillar on convertibles are usually have very strong internal reinforcements. Airbags
The Mazda MX5 has dual front airbags, side impact airbags, and 3 point safety belts with pretensioners and force limiters.
The Active Bonnet (Hood) is not on vehicles sold in North America. However, vehicles that fall under the European New Car Assessment Program (Euro NCAP) do have this feature. Active Bonnet (Hood) is designed to mitigate shock to the head in the event the vehicle collides with a pedestrian. Designed to activate with a defined speed range, the system causes the rear end of the bonnet (Hood) to pop up when an impact exceeding a certain threshold is detected, creating a shock-absorbing space between the bonnet and the engine.
Here’s a great video that explains how it works.