Correct, but this isn't taking into consideration the difference between PURPOSEFUL attacks and accidents. The vehicle regulations helped prevent a ton of accidents that were killing people and improvements in technology all helped making traveling a less risky activity. Protecting yourself with a firearm isn't a risky activity, but some regulations and technology have been enacted already to help keep it safe.
All those safety things don't stop this:
https://en.wikipedia.org/wiki/Vehicle-ramming_attack
Sure it's a complex problem, and all of the different factors should be taken into consideration. All the potential solutions should be taken into consideration. Lets start simple, with two factors.
1. Weapon
2. Person
What are we more likely to be able to change with additional understanding and regulation? What works best without sacrificing our rights?