When the Tier rating program started in the U.S. in 1996, the goal was to reduce nitrogen oxide and particulate matter from the exhaust of diesel engines. Since then, engine technology has been ...

Tier 4 vehicle restrictions go into effect on Pennsylvania highways at 12:01 a.m. Sunday. Tier 4 is the second most-restrictive level for PennDOT. Officials are urging everyone to avoid driving during ...

PennDOT has placed a Tier 4 vehicle restriction on the full length of Interstate 83 starting at 12:01 a.m. Thursday and is urging residents to avoid unnecessary travel during the storm. Tier 4 is the ...

July marks the 10th anniversary of Wabtec Corporation’s Evolution Series Tier 4—one of the most modern diesel locomotives serving North America and the first freight locomotive to meet the U.S.

PennDOT has placed a Tier 4 vehicle restriction on the full length of Interstate 83 starting at 7 p.m. Wednesday and is urging residents to avoid unnecessary travel during the storm. Tier 4 is the ...