Correction: An earlier version of this story incorrectly said the American Trucking Associations had lobbied against the rule. The organization said it opposed rushing the rule-making process, but did not lobby against the proposal. This version has been corrected.

Authorities investigate the scene of a charter bus crash on northbound Hwy. 99 between Atwater and Livingston, Calif., on Aug. 2, 2016. (Scott Smith/Associated Press)

Continuing its quest to relieve industries of regulatory burdens, the Trump administration has scrapped a proposal that would have required truck and bus drivers and railroad engineers to be tested for a disorder that could cause them to fall asleep on the job.

In pulling back the proposed rule, the Transportation Department acknowledged that moderate to severe sleep apnea is “an ongoing concern . . . because it can cause unintended sleep episodes and resulting deficits in attention, concentration, situational awareness, and memory,” putting passengers and other drivers at risk. The agency concluded, however, that existing safety programs are adequate.

Advocates of the testing denounced the decision.

“We don’t want train engineers with undiagnosed sleep apnea, who actually hold lives in their hands, to fall asleep at the switch, and we don’t want big-rig drivers to doze off at the wheel,” Sen. Charles E. Schumer (D-N.Y.) said at a news conference Tuesday. “This abrupt and uncalled-for withdrawal by USDOT commemorates a disaster waiting to happen.”

Christopher O’Neil, a spokesman for the National Transportation Safety Board (NTSB), said the panel, which has long sought such a rule, is disappointed by the decision.

The Obama administration last year proposed to test bus, truck and rail operators for sleep apnea and treat those found to have the disorder.

“Sleep apnea has been in the probable cause of 10 highway and rail accidents investigated by the NTSB in the past 17 years, and obstructive sleep apnea is an issue being examined in several ongoing NTSB rail and highway investigations,” O’Neil said. “The need for this rulemaking is well documented in the safety recommendations issued to both the [Federal Motor Carrier Safety Administration] and [the Federal Railroad Administration], regarding obstructive sleep apnea.”

DOT officials did not return calls seeking comment.

The American Trucking Associations, which said it had opposed “rushing the rule making process,” supported the move.

“ATA has supported getting this right, even if that takes a little longer,” the organization said in a statement. “Data and science matter, and FMCSA, ATA, carriers and drivers have been working to get solid data to support a rule making. Pulling this preliminary advanced notice of proposed rule making doesn’t change that, and we support the process to better understand and address apnea and fatigue for commercial drivers.”

But Sarah E. Feinberg, who was the administrator of the Federal Railroad Administration during the Obama administration and is an advocate of sleep apnea testing, condemned the decision.

“This is a condition that we know has meant unnecessary deaths and injuries. And there is such an easy — and inexpensive — solution,” she said. “There is no reason to withdraw a rulemaking like this other than because you don’t understand the science or because you’ve chosen to ignore it.”

More than 25 million Americans are estimated to suffer from undiagnosed sleep apnea. The disorder results in reduction or cessation of breathing during sleep. In one study, the American Academy of Sleep Medicine found that for people who have sleep apnea, eight hours of sleep can be less refreshing than four hours of ordinary, uninterrupted sleep.

Pilots already are tested for the disorder, which disrupts normal sleep and contributes to drowsiness during the day. In 2015, the Federal Aviation Administration reported that more than 4,900 licensed pilots were being treated for it.

Investigators said sleep apnea was to blame for a December 2013 commuter rail crash in New York that killed four people and injured 70. The NTSB determined that Metro-North engineer William Rockefeller nodded off just before taking a 30-mph curve at 82 mph.

After the crash, Metro-North examined 320 engineers and determined that about 18 percent of them had sleep apnea.

The NTSB cited a history of rail incidents it has investigated in pushing for sleep apnea testing:

•Aug. 17, 2014: Two long freight trains collided in the middle of the night in Hoxie, Ark., and two crew members on one of them were killed. The NTSB determined that the engineer who died was tired and “likely asleep due to his diagnosed but inadequately treated moderate sleep apnea.”

•May 25, 2013: Two freight trains collided at 2:30 a.m., sending the two crew members on one of them to the hospital. Two automobile drivers also were hospitalized after the derailment caused a bridge to collapse. The NTSB said the engineer on one train “likely had undiagnosed obstructive sleep apnea . . . and this likely resulted in fatigue that contributed to this accident.”

Although sleep apnea wasn’t always the cause, the National Highway Traffic Safety Administration said that falling asleep at the wheel caused the deaths of 846 people in traffic crashes in 2014.

A study by the AAA Foundation for Traffic Safety estimated that drowsy driving causes 300,000 crashes each year.

The NTSB suggested that sleep apnea can raise the risk of a motor vehicle crash by up to seven times, and it noted that heavy trucks are involved in nearly 1 in 8 fatal crashes.

The NTSB pointed to two crashes in particular:

•June 26, 2009: A tractor-trailer traveling at 69 mph plowed into vehicles backed up by a minor crash on Interstate 44 near Miami, Okla. Ten people in cars died, and six were injured. The NTSB determined that the truck driver was suffering from “acute sleep loss” and “mild obstructive sleep apnea.”

•May 31, 2011: Before dawn, a bus struck a cable barrier near Doswell, Va., overturned and rolled onto its roof, killing four passengers and seriously injuring 14. The NTSB concluded that the driver fell asleep.