California Code, Education Code - EDC § 39809.5

(a) The sum of the state aid received and the parent fees collected in a fiscal year may not exceed actual operating cost of home-to-school transportation in that fiscal year.

(b) If excess fees are collected due to errors in estimated costs, fees shall be reduced in succeeding years.

(c) The governing board shall certify to the county superintendent that districts have levied fees in accordance with law, and that fees have been reduced and excess fee revenue eliminated whenever excess fees have been charged.