Unless children can get to school on time and safely, the world’s best teachers can’t help dig South Carolina out of its educational slough.

And unless the House-passed budget’s allocation for new school buses grows a lot, it will be increasingly difficult for students to do just that.

Why? Because the oldest and most polluting school bus fleet in the country will continue to break down more, frequently require more maintenance, use more gas and fail more often to get children to school on schedule.

But the real cost of using buses that are too old even to be under warranty is the risk of a serious accident in which children are injured or killed.

State Superintendent of Education Mick Zais has demonstrated that he is fiscally conservative. Last year he didn’t even ask for an increase in his department’s budget.

This year, he says he needs $46 million for new school buses — $34 million from the state’s capital reserve fund and $12 million from unclaimed lottery prize money to replace old, unreliable buses.

Instead, the House budget includes only $10.5 million from the capital reserve fund and not one dime in unclaimed lottery prize money.

Besides being woefully inadequate ($1.7 million less than last year), the allocation would be non-recurring revenue, meaning it would not be guaranteed in subsequent budget years.

And it fails to meet the General Assembly’s own mandate that a portion of unclaimed lottery prize money be used for school bus purchases.

A 2007 state law also requires the fleet to be replaced every 15 years. It was enacted after The Post and Courier reported on the sorry state of South Carolina’s school bus fleet.

Dr. Zais’ budget request would begin the replacement cycle established by the Legislature — and then ignored. School buses should not be shorted as if they are somehow not essential.

Earlier this year, the state received 342 new buses to be distributed statewide. They are to replace some that are 28 years old, and they were paid for ($24.6 million) mostly by lottery funds and unclaimed lottery prizes. It was the first time since 2006 that unclaimed lottery money was applied to school bus purchases.

We shouldn’t expect help from the governor. Her budget includes no money for school buses. Last year, she vetoed the $12 million school bus allocation. Instead, she advocates transferring responsibility for buses to individual school districts.

The experience of threatened bus driver strikes in Charleston, Beaufort and Dorchester counties suggests that might not be the best model. In contrast, public employees could not legally go on strike.

Older buses can have safety problems and are prone to catching fire. Some have holes in the floor which can allow exhaust fumes to waft in and be inhaled by children. Most lack standard safety features and equipment found on new buses to transport students with disabilities.

The Legislature is ignoring its responsibility by failing to replace school buses on a regular cycle and by failing to provide lottery money on a regular basis for that purpose.

Worse, lawmakers are failing the state by playing fast and loose with students’ safety.