1.people are scared to walk on the streets
2.people are scared to walk the streets
3.people are scared to walk in the streets

1.the attacks make people being scared to walk on the street
2.the attacks make people being scared to walk the street

which preposition should I use here?

See a translation

@shalomAti הולכת ברחוב would be more like in English "walking on the street" to me. At least the way I see it.
I'll try to explain the different ways we say this and what they mean.
Normally one would say "I'm walking down the street" and this would be the most common. It doesn't have to mean literally going down, just walking along the street .
"I'm walking up the street" is more directional. If I'm going to the store and it's a couple blocks away I might say, "I'm going to walk up the street to the store." Again, it doesn't have to mean literally "going up."
Walk along the street. This, I think, would be לאורך הרחוב I think. Just kind of walking along, maybe looking the in shop windows, etc.
As for "walking ON the street" it would apply to something like this. There are no sidewalks on my street so I have to actually walk ON the street instead. Not as safe as walking on the sidewalk.
Then, as I mentioned, "It's not safe to walk the streets" is used in a case where it's dangerous. Or where prostitutes might walk the streets looking for customers. In fact sometimes they call prostitutes "street walkers."