Tripmeter

I am looking to add a secondary trip meter for my car, while Im still investigating the output signal from the speed signal, I am trying to think of the best way to do this. I am guessing I would use a PIC (Probably an 84a or 628) since I've have used the 84 in the past and that the LCD routines are fairly out there since all I would need then to is write a resetable counter. Has anyone already constructed a circuit such as this or know a better way to do so?

Thanks in advance