LOUISVILLE, Ky. (AP) — A total overhaul of bus routes for Louisville's school district turned into a logistical meltdown on the first day of classes because the new plan created too steep a learning curve for the system, district officials said Friday, forcing administrators to cancel two days of classes and leaving parents and state legislators fuming.

It took just one disastrous day for Jefferson County Public Schools leaders to completely reexamine the transportation plan for Kentucky's largest district, which serves 96,000 students. Some kids arrived home hours late on Wednesday, and classes were canceled Thursday and Friday.

“We are reviewing what happened Wednesday to determine where the issues were created, why they happened and how to prevent them from happening again,” district spokesperson Mark Hebert said Friday.

The district deployed a new bus routing system designed by AlphaRoute, a Massachusetts-based consulting company that uses computer algorithms to map out courses and stops. The district has 65,000 bus riders, according to its website.

“There was a big learning curve,” Herbert said of the new transportation plan. AlphaRoute did not immediately return requests for comment Friday.

The overhauled plan was meant to solve a basic mathematical problem for the district: Last school year, it didn’t have enough drivers to cover all the routes. As a result, thousands of kids missed instructional time as some drivers made double and triple runs.

With classes now canceled, the district is reviewing all bus routes and bus stops for efficiency and taking steps to improve communications, Hebert said, while bus drivers continue to practice routes.

Frustrated parents said they wanted to see quick results.

Beau Kilpatrick has five kids attending schools in the district but said the only major transportation problems were with his elementary-school aged children, two girls in the first and third grades. The morning bus was supposed to arrive at 8:38 a.m. but never came, he said. After half an hour of waiting, he drove them to the school a few miles away. In the afternoon, the bus was almost two hours late for pickup.

Kilpatrick said the children had to sit in a school hallway while waiting for the bus to arrive because the cafeteria was already full. Then the children weren't dropped off until three hours later, at 9:15 p.m.

“They were hungry," he said. "They were thirsty. They couldn’t use the bathroom. They were scared because they just wanted to get home,” he said.

The younger child was covered in urine and Kilpatrick had to assure her that she wasn’t in trouble. Their father called it a "complete failure” by the district.

Superintendent Marty Pollio has called it a “transportation disaster” and apologized to students, families, bus drivers, and school officials who had to stay with students for hours as they waited for busses Wednesday. He said the decision to close schools on Thursday and Friday was the most difficult of his career but said it was necessary.

Pollio was set to hold a news conference Friday afternoon.

A group of state lawmakers representing Jefferson County districts called it “the last straw,” saying the debacle “must be the catalyst for change” in the school system.

The lawmakers signaled that they will push for legislation ensuring that students have the right to attend their neighborhood schools. They called for a commission to evaluate splitting up the school system, contending that the district currently is “too big to properly manage.” And they called for changes to the local school board.

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Loller reported from Nashville, Tennessee.