Besides just turning on the AC in your car. Today was so hot and I my butter cream (hi ratio) just didn't want to cooperate. I have to delver ten cakes to a friends party in September and I really hope it's not as hot as today. What do all you wonderful bakers do to avoid damaged cakes? So glad I didn't use Swiss Meringue like I had planned it would have been a disaster. I try to chill my cakes for several hours before delivery.

Sweettreat, some many years back I had a delivery van with no a/c. I was given an order one summer to deliver a cake more than 2 hrs away in the middle of a scorching hot summer. Someone gave me this tip which saved me and I still use it from time to time.

Its a makeshift dry ice cooler. Place you cake in its proper box,
take a heavy packing box larger than the size of your cake with its box. Place some dry ice wrapped in a plastic bag in the bottom of the box, place newspaper or packing paper around the dry ice to keep it in place, Place a cake board the first this box on top of the ice and packing material.
Place a towel or nonslip mat on top of all this and then place your cake on top of everything.
Close the box up and place all that in an extra large plastic bag.
Seal up the bag so air does not escape.

Sounds like a lot of work but it will keep your cake cool for up to 8hrs. Plenty of time to deliver.

Good Luck.

Thank you so much I was wondering about using dry ice. I know my brother uses it to bring back bushels of crabs from Maryland I just wasn't sure if it would be ok to use around cakes.

There you go.. It will work fine with no harm to the cake.

please make sure your vehicle is well ventilated! i'm worried about carbon dioxide build up from the dry ice.

Won't that harm the cake? I don't want anyone to get sick.

no it won't harm the cake, i just want you to have some fresh air

Thank you Metria.

I chill my cakes in the fridge overnight before deliveries. Both the cake and icing is hard for delivery. Both go back to their normal consistancy once brought back to room temp, which takes a while. But since I mostly make wedding cakes, and wedding cakes sit at the reception for a couple hours before cut - there is never any problems.

I deliver wedding cakes all summer in the 100 degree heat...I refrigerate everything overnight, and put them in packing boxes before taking them into the car, then blast the air conditioner. Nothing's melted so far.

Thank you everyone for all your wonderful advice. I always refrigerate my cakes as most of my cakes use a whipped cream filling and require refrigeration. I have ten cakes to deliver in the hottest part of summer so I don't want to end up on cake wrecks. Does anyone know if Frostin Pride or Better cream is more heat stable than regular butter cream? She loves the non dairy frosting's but I hate working with it but I might give in if it's more heat stable.

I use SugarShack's buttercream recipe and I absolutely love it. I deliver to a lot of outdoor weddings and have never had a problem with melting, streaking - nothing.

I just delivered one yesterday, 100 degrees and high humidity. And I couldn't believe it didn't sweat or anything! I cooled my car off for about 20 min before and had the air blasting. I brought a jacket cause it was so cold, but my cake loved it lol
Just keep it as cool as you can and it should be ok!

FromScratchSF posted about Flexi-Freeze ice sheets in another thread. I'm not sure how one would use it though.