How to Carry another helmet while driving?

[WASP77]

Last night, i went to pick up a friend who didn't have a helmet, i had to carry my spare helmet with me for like a 20 minute drive!
i got so confused where to store it! finally i got a back-pack, and squeezed the helmet inside and then carried the back-pack on my back while driving.
i know that wasn't the best thing to do, it aint safe nor comfortable i guess! i was driving my 696 with a big balloon on my back

any ideas / suggestions ?

[stopintime]

I use a cargo net and strap it down to the passenger seat.
If you have nowhere to put the net while riding with the passenger, it can be strapped around the tank.

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[He Man]

i have a book bag with a clip on the side, i just clip around hte chin area of the helmet and let it hang.

[Spidey]

You should ride your bike, not drive it.

I either use a spider-web cargo net or I attach it to a bag or backpack.  Many helmets also come with soft helmet bags that you can wear like a backpack.  I never dangle a helmet off my bike while riding from the helmet holder or try to carry it on my arm. 

[Turf]

+1 cargo net

little elastic cargo nets are awesome and after broken in you'd be amazed at the crap it'll help carry.

[rideserotta]

+1 on backpack.

[erkishhorde]

I place the helmet facing the rear of the bike on the back seat and use 1 short bungee to wrap from my seat hook (Sargent seat) around the chin bar and back on each side. When the helmet is in use I can wither strap the bungees around the tank or tie them around the cinching straps on the sleeve of my jacket.

[DucHead]

If I'm "driving," I put the helmet in the passenger (or back-) seat of the car. 

If I'm "riding," I put a spare helmet in either my backpack or on the seat behind me held down with a bungee net.

[Monster Dave]

If I'm "driving," I put the helmet in the passenger (or back-) seat of the car. 

If I'm "riding," I put a spare helmet in either my backpack or on the seat behind me held down with a bungee net.

[Spck31]

+1 net on the back seat.

[Twizted]

The helmet bags you get when you purchase most new helmets are ok for short trips across town with a helmet in them. Just sling it across your shoulders.