That's much better.
Define exists. Do you mean an object of type car already instantiated and running, or something within persisting storage? With just the code here, there is only ever this one created.
There's an antipattern called a Singleton which would allow you to do this. It forbids direct construction of an object and instead you invoke it statically and it either creates an object for you, or reuses an existing one. Its not the *best* thing to do that typically, but I always say there are exceptions to the rules, so I guess it depends on what you want to do.
header('HTTP/1.1 420 Enhance Your Calm');