The bit where it went wrong is that you placed a period outside the quotes:
code:
var Message = signedincontact.Name+ "has just arrived in is/hers car"+.;
You should place it between the quotes, and thus there's no need for the plus operator. Oh, and maybe you want a space before "has"?
code:
var Message = signedincontact.Name+ " has just arrived in is/hers car.";
Of course, if you simply use Spunky's code, you have everything you need.
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