I have 50 mini cakes to do for a wedding covered in buttercream, I've been trying to figure out a way to transport them in the car. Does anyone have any suggestions? It would be greatly appreciated.

Thank you

Not sure exactly what size your mini cakes are, but could you use a plastic container, but flipped upside down?  (so the cake is on the lid)  

They're about 3". I'm not sure I understand what you mean..

I have good luck with the non skid matting. I live about 10 miles outside of the closest town on a narrow, windy road with lots of hills. . I place my cake board directly on the matting and haven't had any issues..

I don't use the kitchen shelf liner matting. I use the heavier matting that you can get to line the drawers of tool boxes. It comes in a roll so you can cut various sizes and reuse. Its thicker and seems to be a little more or a foam material.   

I usually always have cardboard boxes around from ordering things online.. I would try to carefully pack the mini into boxes and transport them that way. But packing them so there's not from them to slide around in the box. (or i guess you could put some non skid material inside the box).. If you're worried about getting them in and out of the box you could always cut one side of the box off and slide them in then tape the side on to contain them during transport. Hope some of this helps.

i would go to staples and get a 24 inch box (or some number divisible by the diameter of your cake boards) and cut it in half so that you have two box bases. then i would cut down one side so that it's a flap. I would slide the cakes in so that the bases are snugged up to one another and tape up the side. 

repeat. 

I go to Sams and grab their empty flats from the isles.  You would need multiple flats but you should be able to get quite a few cakes in them.  They are pretty strong.  I use them all the time for transporting cakes.  May not be very professional, but they work for me.