Question

double tyres are provided at the near wheel of the truck explain why

Answer 1

not only the near wheels but double tires are provided also on the back this is to reduce pressure on single tyre as we know that trucks carry huge load thus I think you got your answer

Answer 2

If the truck is carrying more weight then it needs balence to go if not it falls down due to heavy weight and to reduce friction also.

Hope it helps you......!☺️☺️