Create another part on the side of an existing part even if rotated?

I'm trying to automatically generate paths for my roads however on curves the parts created clip with the road.

local paths = Instance.new("Model",game.Workspace)
paths.Name = "paths"

for i,v in pairs (game.Workspace.roads:getChildren()) do
    local oldCFrame = v.CFrame
    local oldSize = v.Size
    local vClone = v:Clone()
    vClone.Size = Vector3.new(oldSize.x,oldSize.y,10)
    vClone.CFrame = oldCFrame + Vector3.new(31,0,0)
    vClone.Parent = paths
end

Here's an image of the issue http://prntscr.com/fq4jgo