The Department of Homeland Security does not have a way to measure how effective fencing and barriers are along the border with Mexico, The Washington Post reported Monday.
A Government Accountability Office report in February 2017 found that Homeland Security could not measure how well walls work, where they work best, or whether methods that cost less could work as well, the Post reported.
U.S. border agents can collect "geotag" electronic markers that map illegal crossings and arrests, but Homeland Security does not have a way to tell whether "tactical infrastructure" hinders those crossings, the report said.
This week, DHS officials said they are working with the Johns Hopkins University Applied Physics Laboratory on an evaluation system, which might be ready this year, according to the Post.
President Donald Trump is scheduled to view border wall prototypes in San Diego on Tuesday.
The prototypes are taller and more formidable than any barrier now in place along the border by extending 6-feet underground to prevent burrowing underneath, as well as containing a number of features that resist climbing. One model contains metal spikes, the Post noted.
Each prototype cost $486,000, and DHS officials said the money is worth it due to major downturns in arrests for illegal crossing in areas where tougher barriers have been installed.
The GAO report said that in some areas in California and New Mexico, more arrests occur in areas that already have fencing. In some border cities such as Calexico, Calif., and Nogales, Ariz., illegal crossers can quickly blend in to their surroundings if they can get through, the report said.
The cost of border security is concerning to some critics, such as Sen. Thomas R. Carper, D-Del.
"We're spending money like a drunken sailor," Carper, a member of the Senate Homeland Security and Governmental Affairs Committee, told the Post. "We cannot continue to waste money, so we need to find what works and what doesn't."