Short answers: yes.
Not yet
Calm down.
Long answer.
She's 4yo. That seems huge now, but with my youngest is now 13yo and 4yo is so small, and they are learning. She's just started school, and a lot of children are overwhelmed at first.
All of mine.
Dd1-my most compliant. Ran out in front of a car with no warning at about that age. Never did it before. Car happened to be a police car, which stopped and he got out and told her why she should never do it again.
Dd2 thought throwing a strop and dropping to the floor in the middle of a road was a great attention getter. Tbf it was. 
Ds was more occupied with not getting to school when he was your dd's age. But I remember him on the way home just running straight over a zebra crossing because he was trying to get away as soon as possible.
Any parent that tells you they never had any heart stopping moments is wrong.
I was told they don't really get road safety until age 8yo. Yes she does know better when she's thinking carefully, but you can't trust a 4yo in the heat of a moment.
Not to do it again.
First: Go and give her a hug. Ask her what went well at school. Who did she sit with, what did she have for lunch. Praise her for eating her lunch. Tell her that the craft activity must have looked amazing. Get her smiling and feeling positive.
Then apologise for losing your temper. Yes, that seems silly, and she did deserve it, but you'll actually have more impact on her.
Say that you were scared. You were scared that a car would hit her and she would be badly hurt. (don't go in to killed, that's too much for that age). Grownups do get angry when they're scared too.
Tell her that you are upset that she didn't listen to you, and you love her very much. Remind her that roads are dangerous and it's important she listens to you.
Give her a hug and then go and do something together-even if it's only watching something silly on TV.
She will remember far better than you going up the wall at her. You're not rewarding her for it, you are empathising with her and showing you care.