objects not deleting

The objects do not remove once they get to the location specified in the code below

local composer = require(“composer”)

local scene = composer.newScene()

local physics = require “physics”

local carHit = false

function scene:create( event )

local group = self.view

background = display.newImage(“Background.png”)

background.x = 160; background.y = 245

group:insert(background)

car = display.newImage(“Car3.png”)

car.x = 225; car.y = 400

physics.addBody( car, { density = 0, friction = 0, bounce = 0})

car.gravityScale = 0

car.type = “car”

car.collision = carCollision

leftTouch = display.newRect(69,463,132,120)

leftTouch.isVisible = false

leftTouch.isHitTestable = true

rightTouch = display.newRect(260,463,132,120)

rightTouch.isVisible = false

rightTouch.isHitTestable = true

function leftTouch:touch(e)

if e.phase == “began” then

transition.moveTo( car, { x= 100, y= 400, time= 50} )

end 

end

function rightTouch:touch(e)

if e.phase == “began” then

transition.moveTo(car, { x= 225, y = 601, time = 50})

end

end

function carCollision(self, event)

if event.phase == “began” then 

print(“carHit”)

carHit = true 

display.remove(car)

storyboard.gotoScene(“Scene_menu”)

end

end 

function spawnBlockRight()

 if (carHit == false) then 

  block = display.newRect(230,-75,50,59)

block:setFillColor(0.5,0.6,0.9)

block.isVisible = true

physics.addBody( block, { density = 0, friction = 0, bounce = 0})

block.gravityScale = 0

transition.moveTo(block, { x= 225, y = 601, time = 600})

elements:insert(block)

group:insert(block)

end 

end

function spawnBlockLeft()

 if (carHit == false) then 

 circle1 = display.newCircle(100, -75, 15)

circle1:setFillColor(255,255,255)

circle1.isVisible = true 

transition.moveTo(circle1, { x = 100, y = 601, time = 600} )

physics.addBody( circle1, { density = 0, friction = 0, bounce = 0})

circle1.gravityScale = 0

elements:insert(circle1)

group:insert(circle1)

end 

end

function randomnum()

 if (carHit == false) then

WhichBlock = math.random(1,300)

print(WhichBlock)

end

end

 function spawn()

if (WhichBlock < 150) then 

spawnBlockLeft()

else 

spawnBlockRight()

end 

end

elements = display.newGroup()

function deleteBlocks()

for a = elements.numChildren, 1, -1 do 

if (elements[a].y > 600) then 

elements:remove(elements[a])

print(“deleted”)

end

end 

end

end 

function scene:show(event)

local group = self.view

physics.start()

car:addEventListener(“collision”, car)

group:insert(car)

leftTouch:addEventListener(“touch”, leftTouch)

group:insert(leftTouch)

rightTouch:addEventListener(“touch”, rightTouch)

group:insert(rightTouch)

timer.performWithDelay(10, deleteCar,0)

  

timer.performWithDelay(500 , randomnum,0)

timer.performWithDelay(1000, spawn, 0)

timer.performWithDelay(2, deleteBlocks,0)

end

scene:addEventListener(“create”, scene)

scene:addEventListener(“show”, scene)

return scene