The Mehlville School District will return to a three-tier bus system for students beginning with the 2013-2014 school year.

The Board of Education recently voted unanimously to operate a three-tier bus system instead of the four-tier system that has been in effect since the 2011-2012 school year.

For the three-tier system, 12 buses will need to be purchased in 2014, four buses in 2015 and four in 2017; as opposed to six buses in 2014, four buses in 2015 and four in 2017 for a four-tier system. The total cost for the lease-purchase of 20 buses is $1,525,055.

With a three-tier system, the first and second tiers, which begin at 7:20 a.m. and 8 a.m., respectively, will stay the same. The third tier would start at 8:30 a.m.

Superintendent Eric Knost said he believes a three-tier system is better for academic achievement because of “the unintended consequences.” For example, students’ doctor appointments do not “accommodate” a four-tier system.

“We have seen the incident rates of kids who are taken out of school early go up significantly,” Knost said. “So does that (having a four-tier system) affect student achievement? Absolutely, that affects student achievement. Can I show you numbers and specifically quantify that? No. It’s anecdotal, but (a three-tier system is) clearly a more efficient and more effective way …”

The cost difference between three-tier and four-tier is roughly $60,000 through the lease-purchase, according to Knost.

“What we also found is in analyzing this in great detail — in probably much greater detail than was ever previously analyzed – that the costs outside of equipment are really a wash …,” he said. “The only true cost of going back to a three-tier [system] are the equipment costs.”

The district has buses dating back to 1993 models, and four buses are out “out of commission” and two are close to being out of commission, according to Knost.

Transportation Director Dan Gilman told the board he found three-year-old used buses in Bethalto that Mehlville can purchase for $62,000. New buses cost roughly $90,000, according to Chief Financial Officer Noel Knobloch.

Knobloch said the district received a $20,000 grant toward the purchase of buses and has applied for four additional $20,000 grants, which could be put toward new bus purchases in 2015. The grants are through the Environmental Protection Agency, according to Gilman.

Wohlwend, Point, Trautwein, Bierbaum and Hagemann elementary schools currently are on the fourth-tier, for which school begins at 9:15 a.m.