Aid workers are taking a crack at transporting migrant families from Yuma to Phoenix — a round trip of more than 350 miles — once people have been released by federal authorities.

The pilot program aims to relieve pressure on Yuma, and take advantage of unused space here.

Shortly after aid groups began testing a day shelter to help a growing number of migrant families dropped off in Phoenix, the Border Patrol announced that it would start letting people go in Yuma.

Since then, there have generally been fewer migrants released in the Valley and more in southwest Arizona, said Stanford Prescott, community engagement coordinator for the International Rescue Committee in Phoenix.

“We recently launched a pilot [program] to shuttle asylum seekers from Yuma to Phoenix, in order to more effectively and efficiently welcome these families to the United States,” he said.

Arizona Rep. Raul Grijalva has asked the acting Homeland Security secretary why Yuma has seen more migrant families, while space for them in Phoenix has gone unused.

Grijalva, a Democrat, said he brought the issue up again at a meeting Tuesday with the acting commissioner of Customs and Border Protection.

“He indicated to myself, and a staff person that was with me, that he was going to look into it and get back to us,” Grijalva said.

Aid workers have brought about 100 migrants to Phoenix from Yuma since the trial started. The number of people transferred depends on how much space is available.