Step 1: If the Hat Fits...

Cut a square piece of cardboard to be the traffic cone base/brim of the hat. It can be sized bigger or smaller depending on if you want a wide or small brim.

Cut a hole in the center big enough to fit the wearer's head. I think all styrofoam heads are made so much smaller than an actual human head so adjust accordingly for fit.

Mark a hole to fit the head. Cut it in pie-wise fashion so that you can bend the cardboard tabs out of the way and use them as gluing tabs for the cone structure. Test fit after all the tabs are bent in.

Step 2: Point Things Out...

Cut some long thin strips from your cardboard.

Form the cone shape by gluing one end of a strip to the tabs on the brim of the hat.

Create an inverted V shape the size of the traffic cone. No need to measure or be exact in any size, it will look good later on. You are just trying to rough form a conical shape.

Try to glue in the ends of the cardboard strips to the vertex or point of the cone.

Go around like staves in an old wooden barrel and build up something that looks like a whiffleball cone.

Add enough strips so that you have minimal gap size. Paper mache later will be able to cover the gaps and smooth out the overall shape.

You can glue on additional pieces on the inside to strengthen the structure. It may help to staple some pieces in place as you are gluing since cardboard offers some resistance to staying in place before the glue sets up.

Step 3: Put Your Feet on the Ground...

Glue on additional bits of cardboard to simulate the feet and protrusions on the rubber base of a traffic cone.

Make up any pattern with the pieces to look like an industrial strength molded base.

Step 4: Wrap It to Go...

Paper mache everything to give it a smooth appearance.

Use whatever scrap paper you have laying around that needs to be recycled.

Tear into pieces and saturate with thinned glue. Layer on being sure to overlap pieces.

Give it a day or two to dry and harden up.

Step 5: Make Sure It Stands Out...

The cone was primed with white acrylic paint.

I used acrylic paints for easy cleanup and knew that this would not really be exposed to the elements like a real traffic cone.

The paint is a fluorescent school bus yellow that I added red to get the right color.

I painted the bottom black to simulate the rubber base.

When touching up the black trim on the bottom, I used a rag to wipe up some errant paint and just wiped it all over the cone. It smeared some of the paint and I liked the weatherbeaten look to it. You can also apply a weathered look by drybrushing - dab just a drop of black and white paint on your brush, apply feather strokes to get graying and a weather worn look.

Traffic cones have an added strip or strips of retroreflective tape(tiny glass mirror beads are embedded in the paint) to increase visibility when lights shine on it, a safety feature especially useful when car headlights bounce off the traffic cone to warn the driver of something ahead.

Since I don't have any real retroreflective tape, I freehanded two bands on the cone by painting the borders of the strips leaving an exposed strip of white. You can also glue and sprinkle some glitter on there later to increase the realism of your traffic cone. I've got a batch of glass microbead sandblasting media that I might try to see if it is similar to the stuff they use to dust the freshly painted lines in the street.

Note that if you actually did use a tape to apply the band, it would not lie flat on the conical shape as you went around. The tape piece would need to be somewhat arc shaped to fit correctly.

You can stencil on some markings to indicate the owner of the traffic cone: Dept of Traffic, Utility Company, property of the BUG Company - Brooklyn Union Gas, etc.

When finished, wear it on your head. May be better than a lampshade.

Now look out and watch people get out of the way...

Enjoy!