I'm not sure if this is normal behavior, but in races where you begin from a stop the countdown seems a bit odd. I would expect the lights to blink out one by one in a 3-2-1-Go fashion, but it just beeps and has the lights go out twice... once when I would expect the 3, and the several seconds later at Go. This makes it hard to know when the Go will be and my revs are usually not where I want them to be.
Is this some sort of glitch or am I just so naive I don't even know how a race launch works?

Is the lights and the start consistant with every race or are they different? If its consistant it may just be how the game was made(I've never played it so its a guess). Just need to watch how it happens and adapt when you rev to how they set the lights.

I checked again, before the race begins there is a tone/beep there are 4 lit red lights on the lightboard and 1 unlit green light. Then after a few seconds there is another tone and all the lights go out. They don't go out one by one or anything like that. I could just be assuming things, but I'd think if they went out one by one in a countdown it'd be easier to know when the race is going to begin so you can be on the throttle but not too high on the revs.

It's typical in racing to have the lights (I believe in F1 there are 4 of them) go on one by one, and then the start signal is when they all go off. There's usually a lower tone when they go on, and a higher one when they all go off.

Yes, that's what I was expecting. But instead in the game they all just go out at once and I'm really not sure why.

I know that means go, but there's no countdown leading up to it. Imagine someone saying "Ready" then waiting... 3-5 seconds, then saying "Go!" It makes it hard to judge when it's going to happen.
Maybe this is just the way the game is made, but I've never seen a racing game like that before, so I'm trying to find out if that's the case.

In all the real races with start from grid I can think of (and also in athletics and swimming, for example) the delay before the start is random, so that one doesn't know when it's going to happen.
So I'd say Toca handles it correctly.