- Reduce the number of school buses required from 650 to 450 (31% savings)
- Redirect up to $18 million per year from transportation into the classroom
- Reduce the number of high school students starting school before 8 am from 74% to 6%
- Reduce the number of elementary school students ending school after 4 pm from 33% to 15%
School planners face a number of goals and constraints that lend themselves to optimization, including:
Goals:
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Help students start each school day well rested and ready to learn
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Maximize resources in the classroom and minimize spending on administration and other expenses outside the classroom
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Create a school schedule that is convenient for parents and students
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Improve student health, safety and welfare
Constraints:
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Limited resources: financial, human (bus drivers and teachers), infrastructure (school buses)
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Students at different ages (elementary, high school) benefit from different sleep schedules
Recent research demonstrates that early high school start times are bad for adolescent health, and contribute to obesity, depression, traffic accidents, diminished academic achievement and cognitive ability.
In 2017, Boston Public Schools announced the Boston Public Schools Transportation Challenge.
The goal?
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Improve bus routes to save money, reduce pollution and let high school students sleep later
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Adjust school start times to increase convenience for students and parents, and to better fit natural sleep cycles for students of different ages who have different sleep requirements
A group of Julia researchers from MIT took up the challenge, and devised the winning solution.
How did they do it?
They leveraged Julia’s JuMP optimization package to solve the School Time Selection Problem (STSP) using a new algorithm they developed called Bi-objective Routing Decomposition (BiRD).
And what were the results for Boston Public Schools, students and parents?
In the first year alone (fall 2017), Boston Public Schools
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Took 50 buses off the road, reducing pollution, traffic and cost
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Saved $5 million per year in taxpayer funds for student transportation, to be redirected into the classroom
Furthermore, Julia researchers identified an optimal solution that, if fully implemented, will:
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Reduce the number of buses (and associated pollution, traffic and cost) even further, reducing the total number of buses by 31% from 650 to 450
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Save up to $18 million per year in taxpayer funds for student transportation, to be redirected into the classroom
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Reduce the share of high school students starting school before 8 am from 74% to just 6%, improving student health, welfare and performance
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Reduce the share of elementary school students released after 4 pm from 33% to 15%
