U.S. regulators have declared  that they are reopening a proposal to boost fuel efficiency of medium and heavy duty trucks in the USA through 2027 calling for additional public comments on the planned toughening but bring a sharp response from the union representing auto workers.

The decision by the U.S. National Highway Traffic Safety Administration (NHTSA) and Environmental Protection Agency to consider additional public comments until the 1st April comes during a sharp slump in U.S. large truck sales that has sparked thousands of layoffs.

Key United Auto Workers (UAW) leaders met with NHTSA administrator Mark Rosekind and other officials in Washington on 25 Febuary to raise concerns that a final regulation “that pushes the stringencies too far could have serious impacts” on manufacturers, according to the NHTSA summary of the meeting released this week.

The White House has made improved fuel efficiency for cars, trucks and larger vehicles a cornerstone of its environmental policies.

In June, the Obama administration said its proposed 2021-2027 medium/heavy duty truck rules would cut carbon dioxide emissions by approximately 1 billion metric tons, and reduce fuel costs by about $US 170 billion, and reduce oil consumption by up to 1.8 billion barrels over the lifetime of the vehicles.

The standards for vehicle and engine performance would apply to semi-trucks, large pickup trucks and vans, buses and work trucks.

A slump in U.S. commercial truck sales has accelerated with

orders for Class 8 highway prime movers fell 25 per cent in 2015 with 284,000 vehicles sold during the year and predictions are that it could drop as low as 250,000 this year.

January orders were down 48 per cent on the the same month last year.

The UAW told the NHTSA last week that it had serious concerns about whether manufactures could “maintain their financial solvency, production capabilities, employment levels, and support of pension obligations if stringencies are pushed too far.”

The UAW told the NHTSA “that presently heavy truck orders are down, resulting in layoffs for thousands of its members.”

Daimler Trucks said last month it would cut 1,250 jobs in North America, Volvo said it would reduce its North American production while Caterpillar as reported in Truck e-News announced it would end production of its on-highway vocational trucks.