comment: >
  
  Steel, which is iron and carbon, is in vast abundance on our planet.
  Sure you COULD make a car entirely from titanium, but it is a rare metal and extremely costly.
  What about lead, you might counter? Pure lead is not as toxic as you'd think and would be safe in a vehicle. But lead is extremely heavy and soft, so it would deform too easily both in manufacturing and in crashes.
  Steel is easily treatable to be rust resistant and also cheap to manufacture. It's also very strong. Steel will not be replaced any time soon until we can mass produce carbon fiber or aluminum in significant quantities that make it cheaper than steel.
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  Hey check out my gold car. Only costs a million. Handles like crap. Weighs as much as tank. >
  
  Stainless steel is a little more expensive and heavier than aluminum, and more costly to make.  
  But obviously more viable than gold. >
  
  Gold is like 4 times heavier than stainless steal. It’s dense as fuxk. >
  
  Sorry, I edited. I meant stainless steel is heavier than aluminum. Which cars are made from aluminum. >
  
  Between cost and material strength, it isn't worth it to use other metals. >
  
  The Delorean was brushed stainless steel with no paint or clear coat. >
  
  It's really a cost/benefit. It's cheaper to have steel and paint it properly than to use other things.
  I had a project in a materials science class. We speccd bronze for corrosion. We pitched it hard but ultimately they were unswayed....the academic professor with 0 profit motive still favored steel.
  In real life I've seen exquisitely expensive copper alloys in sewage system compnents and ship propellers. Rust is expensive there, so they cough up the money. >
  
  Todays cars body panels are primarily made of galvanized steel and aluminum.  The latter will slightly oxidize but never “rust”. The former is quite corrosion resistant unless it’s scratched and not repaired.  Compare these to 70’s cars that had rust perforation in 7 years.  At a similar time (80’s), stainless steel exhaust systems were introduced.  Before that there were profitable shops just to replace rusted mufflers.  Midas rebranded to cover many multiple issues.