School start times will remain unchanged in the St. Paul School District in 2015-16.

A divided school board on Tuesday backed Superintendent Valeria Silva's recommendation to delay plans to move high school start times to 8:30 a.m. in favor of additional study on busing options, including a potential partnership with Metro Transit.

Board Member Jean O'Connell, who was on the losing side of the 4-3 vote, said that she didn't want to see the district wait to make changes in 2016-17 "when we know this is the right thing to do for our high school kids."

Until a series of recent public hearings, St. Paul seemed poised to join the growing number of districts that have pushed back start times for their high schoolers.

Student performance rises, and absences and tardiness decline, when teens get more sleep, studies show.

But the district's insistence upon not adding to busing costs resulted in a proposal to shift a group of elementary school students into new 7:30 a.m. starts — raising objections from parents who were upset about potential disruptions to family routines.

Board Member Anne Carroll suggested last week that the district could try to find the $8 million to $10 million needed to rejigger bus schedules to satisfy both high school and elementary school families. That proposal was not advanced during Tuesday night's debate, however.

Metro Transit now buses high school students in Minneapolis, and has worked with St. Paul in recent months to see if it could help resolve the elementary school concerns by easing the district's high school workload. For now, however, the efforts have come up short, officials say.

"We moved every rock we could move" in recent months, Silva said.

Now, she said, the district will dig deeper into the Metro Transit possibilities and explore creative options within its own transportation department.

Anthony Lonetree • 651-925-5036