The agency says it based its decision to maintain the 50 percent rate on data from surveys conducted in 2012.
Data from that survey showed, FMCSA says:
-Positive drug tests rose 4.1 percent in 2012 from 2011.
-Positive rates of drug tests initiated from reasonable suspicion jumped sharply from 2010 to 2012, according to the survey: 2010’s positive rate was 5.6 percent, 2011’s 15.7 and 2012’s 37.2 percent.
-The rate of total positive drug test results reported to the DOT from federally certified labs saw a slight jump from 2011 to 2012 — 95,427 in 2011 to 97,332 in 2012.