Why am I so scared of freeways?

My mom doesn't like driving freeways because theres usually too much traffic where I live in LA. So usually she drives the local streets. I have heard that the local streets is actually more dangerous than driving the freeways? When my dad drives the freeway it actually makes me more nervous especially off ramp and when he merges on an exit. And the fast speed does not help either, even though I'm not the driver. I felt like we have no control of the car and it will crash into someone when we're switching lanes. I feel even more worse when it comes to traffic, And all the freeway accidents I see on TV all the time makes me so nervous. Why am I feeling this way?