El Nino will have a major effect on US ground transportation and it looks to be a positive one. Temperatures are forecast to be warmer in the Midwest and Northeast. These regions have been absolutely rocked the past two Winters by Winter snow storms lasting into March. Chicago is largely considered to be the freight capitol of the United States and New Jersey has some of the highest traffic ports on the East Coast. The country may see more rain as opposed to snow. Rain does not have a large effect on ground transportation as it does not paralyze interstate systems and local roads like snow can. Here is a pattern of what types of weather this El Nino can bring:
The Western region of the country desperately needs rain and could cause flooding with a major influx of rain this winter season. The Weather Channel has an in depth article about the effects and patterns of an El Nino weather cycle.