How do I make so a player can walk through a wall, but nothing else can?

I want to make a pathfinding script to a car, but the car should only be able to drive on the roads. Therefore I want to create a wall that the players can walk through, but not an NPC car.

I made a simple pathfinding script, but I don't know how to make it so it can't go off the road.

while true do
    path = game:GetService("PathfindingService"):ComputeRawPathAsync(workspace.Start.Position, workspace.Finish.Position, 400);
    points = path:GetPointCoordinates()

    game.Workspace.Points:ClearAllChildren()

    for p = 1, #points do
        part = Instance.new("Part");
        part.FormFactor = Enum.FormFactor.Symmetric
        part.CanCollide = false
        part.Size = Vector3.new(1,1,1)
        part.Position = points[p]
        part.Anchored = true
        part.BrickColor = BrickColor.Gray()
        part.Parent = game.Workspace.Points     
    end

    wait(0.5)
end

Please help. Thanks!