I made this cake for a neighbor friend.
Actually, the Boy gave me the idea for the sirens. He brought home a bag of candy from preschool (a typical "snack" there...don't get me started) and proceeded to divide out the pink, blue, and green candies. He gave me the blue ones (because blue is my favorite color), he ate the green ones (because green is his favorite color), and when his sister got home from school, he gave her the pink ones (you get the idea). However, she didn't much care for the cherry-flavored tootsie rolls and gave them back to him. While I worked on the car cake, he carefully unwrapped each candy and then handed them all to me in one big sticky clump.
"Here, Mommy," he said cheerfully, "maybe you can use this for your cake!"
At that point, I still hadn't decided how I was going to do the sirens. I didn't want to use all frosting so I though I'd frost a Kit Kat, then use decorator gel to get a shiny look but I was out of that candy (soooo unlike me). I had been weighing the pros and cons of waking up Baby to make a run to the store when I got the Boy's little gift. The right color, already shiny, and easy to mold into shape. Perfect!
The "spare tire" was for the Birthday Boy's candle.