Luis Segura, a construction worker from El Salvador facing deportation, recently spent more than six months behind bars at an immigrant detention center in the Mojave Desert. His stay, at $118 a night, cost taxpayers about $22,000.

A few months ago, with his case still pending, Segura was released from detention on condition that he wear a GPS tracking device on his ankle and check in twice a week with parole officers. The cost: about $8 a day.

With immigrant detention levels at their highest point in history — last year, the government spent roughly $2 billion to detain more than 400,000 people — there is a growing push for cheaper alternatives.

Last fall, dozens of members of Congress asked President Obama to do away with a quota that requires the government to pay for 34,000 beds in detention centers each night. Instead, they urged greater use of ankle bracelets and various types of electronic and in-person monitoring programs.

Advocates from groups as diverse as the American Civil Liberties Union and the conservative Heritage Foundation have come out in support of such alternatives. According to Immigration and Customs Enforcement officials, about 90% of immigrants in those programs comply with the requirements and show up for required court hearings.

Though Obama has not moved to eliminate the detention quota, his 2015 budget proposal for the Department of Homeland Security signals a shift.

The proposal calls for a reduction to about 30,500 beds per night, which would save $185 million annually. At the same time, the administration is calling for a slight increase to about $94 million in funding for the alternative programs.

Ruth Epstein, legislative policy analyst with the ACLU, said Obama should go further. She called the detention mandate “massive micromanaging on the part of Congress” and said the categories of people eligible for alternative programs should be expanded.

Under current law, the vast majority of those in ICE custody are subject to mandatory detention to ensure that they show up for their immigration hearings and are deported if a removal order is issued.

Those who are held include recent border crossers facing deportation, those who illegally reentered the United States after previously being removed, legal residents who have been convicted of crimes and those seeking political asylum.