CHICAGO — The school year began more than six weeks ago for Chicago Public Schools. But Angel Alvarez’s third-grade daughter, who is visually impaired, hasn’t spent a day inside a classroom.

On Aug. 28, two days before Decatur Classical School was supposed to resume classes, Alvarez received a phone call saying the bus service for his daughter had been canceled because of the Chicago school system’s bus-driver shortages.

Alvarez, a medical researcher, said his daughter still does not have a way to get to school — he works long hours at a lab, and his wife is legally blind. So for now, with no remote option made available, Alvarez’s 9-year-old is at home, using workbooks he bought her instead.

“I’m angry,” Alvarez said.

While bus-driver shortages are plaguing school districts nationwide during the pandemic, Chicago’s predicament is heightened: One hundred of its contracted drivers quit the week before school started, an exodus that officials and bus companies say was driven by Chicago’s vaccine requirements, which officially go into effect Friday. It has left one of the nation’s largest school districts 500 drivers short in total — and left thousands of students in need with no bus route at all.

Chicago Public Schools provides bus services, which it outsources, to about 16,000 students who have special needs or who are enrolled in magnet or gifted programs, like Alvarez’s daughter, if the school is 1.5 to six miles from their home. When the school year began, Chicago reported that 2,100 of those students were without transportation, including 910 with disabilities whose Individualized Education Plans (IEPs) mandated transportation.

Those numbers have grown since. In a recent letter to the Illinois State Board of Education, Tatiana Oriaikhi, assistant general counsel for the Chicago Board of Education, said that more than 2,400 students with transportation mandated in their IEPs now don’t have it.

“Like many other school districts across the country, Chicago Public Schools continues to adjust amid a national bus driver shortage exacerbated by the COVID-19 pandemic,” the district said in a statement to The Washington Post. “The number of students who rely on Chicago Public Schools-provided transportation has increased due to incoming requests entered in the past month. The number of buses and bus routes were reduced amid the ongoing driver shortage.”

Chicago Mayor Lori Lightfoot (D) said the district received late notification of the driver shortage from third-party contractors after the August announcement of the Oct. 15 vaccine mandate for city employees and contractors. The mandate allows for twice-weekly testing for those who are not fully vaccinated.

Even before the late resignations, the district knew it was short 400 drivers, according to Oriaikhi’s letter. After a no-bid contract was approved by the Chicago Board of Education in June, an Illinois vendor called Christopher Toczycki Inc. implemented a “run tiering solution” that used algorithms to “optimize the scheduling of bus runs” and the “utilization” of bus aides in the district.

According to the contract, the vendor relied on school data from two years ago to slash and combine 3,500 bus runs into 1,100 routes, staggering departure and arrival times of 5,500 students to accommodate the special-needs, gifted and magnet school students who need buses this year. As a result, the district avoided the need for “approximately 650 additional buses and 330 additional bus aides,” the contract said.

Critics say the approach is not working.

“It appears the district was more concerned about saving money and optimizing cost efficiencies rather than prioritizing students with disabilities,” said Chicago special-education advocate Terri Smith-Roback.

Some of the resulting changes have mystified parents such as Alvarez and Robert Nicholson, whose 9-year-old son has an IEP with a transportation requirement. The district first changed Nicholson’s son’s route so that he would have to get on a bus at 6:30 a.m. and ride for over an hour, for what would be a 20-minute ride on public transit. Then the route was canceled.

The district offered some families disrupted by the route changes $1,000 as school began, and they could opt to take $500 monthly payments if they decided to self-transport for the entire year. Nicholson ultimately decided to have his son take public transit instead of the school bus, calling the entire process “frustrating.”

“You get the impression that the longer you keep your kid in a Chicago public school, the more harm you’re doing to them,” he said.

Danielle Bridges, a preschool teaching assistant and mother of two, said she had not received any self-transportation compensation so far. She first had tried to arrange private transportation for her daughter and even advertised on Nextdoor, asking whether anyone wanted to drive her daughter to school as a part-time job.

“This is poor planning,” Bridges said. “Part of it is the vaccine mandate, but it can’t be all of it.”

At the beginning of this school year, Lightfoot said her administration had been in talks with ride-hailing companies Lyft and Uber about providing transportation to students. The online policies for both companies, however, bar unaccompanied minors from traveling with most carriers. The district recently said it enlisted two cab companies to transport 150 students in buses and 50 students in vans, accompanied by bus aides.

Such solutions, though, can appear haphazard. For three weeks, Minnie “Min” Zhou, a nurse anesthetist, and her husband resorted to taking vacation time from work to drive their 3-year-old daughter with special needs to school. (Zhou said she and her husband have not been offered self-transport compensation.) Eventually, Zhou said, a third-party contractor began sending a van to pick her daughter up — but it didn’t have car seats. Zhou lent hers to the transportation company for two days.

Illinois state legislator Lindsey LaPointe (D), whose district includes parts of Chicago, said she has been fielding phone calls from parents in her district about the busing issues. Like them, she has been frustrated by the communication from Chicago Public Schools.

“The fact that this was a scramble and continues to be a scramble is really devastating,” LaPointe said.