Relevance of 'public' constructor in an abstract class

Is there any relevance of a public constructor in an abstract class? I can not think of any possible way to use it, in that case shouldn't it be treated as error by compiler (C#, not sure if other languages allow that).

Sample Code:

internal abstract class Vehicle
{
    public Vehicle()
    {            
    }
}

The C# compiler allows this code to compile, while there is no way I can call this contructor from the outside world. It can be called from derived classes only.

So shouldn't it allow protected and private modifiers only?