One last box to check in USC’s rebuild: winning consistently on the road

A charter bus idled outside Galen Center on Wednesday afternoon with its underbelly open waiting to ferry USC to Los Angeles International Airport. It was an ominous portent.

As the Trojans (15-2 overall, 2-2 in Pac-12 Conference play) prepare for an important series against Utah (11-4, 2-1) and Colorado, they stand on the cusp of contending in the Pac-12. The rebuild of their program under Coach Andy Enfield is almost complete. However, one benchmark remains: consistently winning Pac-12 games on the road. In Enfield’s three-plus seasons, USC has won four such games.

Stealing a win or two this week would be useful. No. 25 USC has embarked on the toughest five-game stretch of its season. It will return from the trip to play Arizona, Arizona State and UCLA.

The mountain trip, which for USC often means swings of about 4,000 feet in altitude and 40 degrees in temperature, can be bedeviling.

“These two road trips, whoever made these two teams together, it’s kind of messed up,” shooting guard Elijah Stewart said. “You might even get sick.”

Winning on the road in college basketball is difficult under any circumstances. According to Collegiate Basketball News, which examined teams’ records in their current arena, home teams win about twice as often, 68% of the time. Only a tiny fraction of Division-I teams, 5%, had losing records at home.

The Trojans’ struggles have been more acute. Last season, USC won just two conference road games — and one of those was across town at UCLA. (The Trojans did win their first conference road game this season, over a hobbling Oregon State team.)

Enfield said he had yet to find a satisfactory answer to why road games have been so difficult.

“I certainly don’t have an explanation,” he said.

Stewart said college road trips can be disorienting. Much of USC’s roster probably hasn’t left Southern California very often.

“You’ve got to go to all these foreign places,” he said. “We’re about to go to Utah. I know all our 50 states. And I know all seven continents. But I really don’t know where that’s located. Whenever you think about going to Utah, you really don’t know where that’s at. All you know is it’s cold.”

On top of that, he said, “you get out of your routine.” The players sleep in unfamiliar beds. Stewart said he always ends up with a sore throat after traveling to Utah, Colorado or the Washington schools. Players can’t stick to their typical pregame habits. There’s not always a gym handy to get up shots.

The crowd doesn’t help either.

“You know, we’re people’s children,” he said. “We like being treated and talked to nice. But we go to road games, you hear the foulest stuff.”

Enfield noted that experience can help in road games, and “unfortunately for us, we’ve always been one of the younger teams in the country, including this year,” he said.

He said the best way he knows to improve a team’s road chances is simple: be better at basketball.

USC has not been playing its best basketball since the Pac-12 season started. Part of that can be attributed to Stewart and guard Shaqquan Aaron, who have both fallen into shooting slumps. They have combined to make just 34% of their shots during conference play.

The shooting woes, like most of USC’s offensive ailments, can be connected to the loss of forward Bennie Boatwright to a knee injury. Stewart said without Boatwright the floor hasn’t been as spaced.

Boatwright is still “a couple weeks” away from a return, Enfield said.

Aaron suggested the slump may just be a slump.

“It happens,” Aaron said. “It happens to the Kobe and Jordans of the world.”

Aaron, once a starter, saw his playing time dip as his productivity declined. He has played a total of 25 minutes in USC’s last two games against bigger lineups.

“There’s a good chance he’ll play more on this road trip,” Enfield said. “But it’s to be determined.”

NEXT UP

USC VS. UTAH

When: 6 p.m. PST., Thursday.

Where: Jon M. Huntsman Center, Salt Lake City.

On the air: TV: Pac-12 Networks; Radio: 690.

Update: Despite its first home loss of the season, 74-73 to California in the final seconds on Sunday, the Trojans’ didn’t budge in the Associated Press media poll, remaining at No. 25.

Utah has lost three times to ranked teams: No. 12 Butler, No. 15 Xavier and No. 16 Arizona.

The Utes have six players averaging double figures. Forward David Collette leads the team with 15.4 points per game. He and another transfer, Sedrick Barefield, did not play in Utah’s first eight games because of NCAA eligibility rules. Both have since become impact players.

zach.helfand@latimes.com

Follow Zach Helfand on Twitter @zhelfand