On Fri, 23 Jan 1998 07:49:50 -0500 Anders Eliasson
<anders.eliasson@INTERTEX.SE> writes:
>Hi,
>
>I'm building a PIC-based ranging system.
>I need to measure the distance between moving vehicles and have some
>problems doing this.

>
>Does anyone have experiences in this field?

This is one of the topics that the government can be convinced to throw a
lot of money at.  Consequently, there is a huge amount of currently
active research in this field.  Look for "IVHS" (Intelligent
Vehichle-Highway System), etc.   The problem is (as you would imagine)
not simple.