Not a great parallel, DD.  Over the years there have been hundreds of changes made to make automobiles safer.  Many of them specifically designed to make children safer as they ride in automobiles.  Seatbelts, airbags, requirements regarding "child seats", crumple zone frame designs, and scores of other design/safety improvements.  Children are safer in autos today than they have ever been in the past.  

I would suggest the exact opposite is the case with firearms.  First, by their very design, many (virtually all which have been used in mass shootings) are built to kill other people.  They are not hunting weapons.  They are weapons of war.  Additionally, high-capacity magazines are readily available, enabling mass shooters to kill far more victims before "reloading."  Guns are, by their very purpose, deadly.  

We register automobiles...but not firearms.  We license all drivers.....not firearm owners. If you like your comparison, great, let's up the ante on gun control...