Railroads that haul volatile crude shipments have reached an agreement with U.S. transportation officials to adopt wide-ranging, voluntary safety measures after a string of explosive and deadly accidents.

The deal signed Friday calls for oil trains to be slowed from a maximum of 50 to 40 miles per hour through major cities, more frequent track inspections and better emergency response planning along routes that carry trains hauling up to 3 million gallons of crude each.

The new safety steps would begin going into effect in late March and be fully in place by July 1.

After a boom in domestic drilling in recent years, oil trains now travel thousands of miles from oil producing areas, including the Northern Plains, to coastal refineries and shipping terminals along the Mississippi River and other major waterways.

The agreement does not resolve concerns over another hazardous fuel, ethanol, involved in a spate of rail accidents in recent years. It also does not address an estimated 78,000 flawed tank cars that carry crude and ethanol and are known to split open during derailments.

The U.S. Department of Transportation said it would address the tank car issue separately.

By taking voluntary steps, the railroads will be able to act more quickly than if they waited for new safety rules to be drafted and approved by the government, said Robert Chipkevich, a former director of rail accident investigations at the National Transportation Safety Board.

But regulators will have little leverage to enforce the industry’s commitments, he added.

“It’s a positive step,” Chipkevich said. “But certainly there’s nothing to say they would have to continue following those practices. The only way you can enforce something like that would be for regulators to publish regulations and do periodic oversight.”

Federal officials said they would continue to pursue longer-term safety measures and use regular inspections to check for compliance with the industry agreement. With no formal rules in place inspectors could not issue fines or take other punitive measures.

“We expect for this to be a document that is fully adhered to, and are prepared to inspect accordingly and call out the industry as necessary,” Federal Railroad Administrator Joseph Szabo said in a Friday interview with The Associated Press.

The Association of American Railroads represents the major railroads in the U.S., Canada and Mexico. President Edward Hamberger said he expects all of them to sign the agreement.

At least 10 times since 2008, freight trains hauling oil across North America have derailed and spilled significant quantities of crude, with most of the accidents touching off fires or catastrophic explosions.

The deadliest wreck killed 47 people in the town of Lac-Megantic, Quebec. Others have occurred in rural areas of North Dakota, Alabama, Oklahoma and New Brunswick. The derailments released almost 3 million gallons of oil, nearly twice as much as the largest pipeline spill in the U.S. since at least 1986.

“Safety is our top priority, and we have a shared responsibility to make sure crude oil is transported safely,” U.S. Transportation Secretary Anthony Foxx said.

Members of Congress who had pressed for tighter safety rules — including Senators Heidi Heitkamp and John Hoeven of North Dakota and Mark Udall of Colorado — welcomed the industry agreement.