Social cost in neoclassical economics is the sum of the private costs resulting from a transaction and the costs imposed on the consumers as a consequence of being exposed to the transaction for which they are not compensated or charged. In other words it is the sum of personal and external costs. Private costs refer to direct costs to the producer for producing the good or service. Social cost includes these private costs and the additional costs (or external costs) associated with the production of the good for which are not accounted for by the free market. Mathematically, social marginal cost is the sum of private marginal cost and the external costs. For example, when selling a glass of lemonade at a lemonade stand, the private costs involved in this transaction are the costs of the lemons and the sugar and the water that are ingredients to the lemonade, the opportunity cost of the labor to combine them into lemonade, as well as any transaction costs, such as walking to the stand. An example of marginal damages associated with social costs of driving includes wear and tear, congestion, and the decreased quality of life due to drunks driving or impatience. a large number of people displaced from their homes and localities due to construction work.