How to teach road safety

My toddler ran into the road today and found it funny. Dad shouted and smacked her bottom (we never smack her but he found it necessary today as a last resort to show how serious it it as she doesn’t listen and road safety can’t be compromised on).

I am going to be on my own next week with toddler and newborn. I am so worried about road safety now. How can I teach it. I don’t trust my toddler without reigns but dad had been giving her freedom without reigns. Also how would you discipline if she doesn’t listen?

Dad said he was really shook up today.