Environmental effects

Trucks contribute to air, noise, and water pollution similarly to automobiles. Trucks may emit lower air pollution emissions than cars per pound of vehicle mass, although the absolute level per vehicle mile traveled is higher, and diesel particulate matter is especially problematic for health. With respect to noise pollution, trucks emit considerably higher sound levels at all speeds compared to typical car; this contrast is particularly strong with heavy-duty trucks. There are several aspects of truck operations that contribute to the overall sound that is emitted. Continuous sounds are those from tires rolling on the roadway, and the constant hum of their diesel engines at highway speeds. Less frequent noises, but perhaps more noticeable, are things like the repeated sharp-pitched whistle of a turbocharger on acceleration, or the abrupt blare of an exhaust brake retarder when traversing a downgrade. There has been noise regulation put in place to help control where and when the use of engine braking retarders are allowed.

Concerns have been raised about the effect of trucking on the environment, particularly as part of the debate on global warming. In the period from 1990 to 2003, carbon dioxide emissions from transportation sources increased by 20%, despite improvements in vehicle fuel efficiency.

In 2005, transportation accounted for 27% of U.S. greenhouse gas emission, increasing faster than any other sector.

Between 1985 and 2004, in the U.S., energy consumption in freight transportation grew nearly 53%, while the number of ton-miles carried increased only 43%.[17] "Modal shifts account for a nearly a 23% increase in energy consumption over this period. Much of this shift is due to a greater fraction of freight ton-miles being carried via truck and air, as compared to water, rail, and pipelines."

According to a 1995 U.S. Government estimate, the energy cost of carrying one ton of freight a distance of one kilometer averages 337 kJ for water, 221 kJ for rail, 2,000 kJ for trucks, and nearly 13,000 kJ for air transport.[18] Many environmental organizations favor laws and incentives to encourage the switch from road to rail, especially in Europe.

The European Parliament is moving to ensure that charges on heavy-goods vehicles should be based in part on the air and noise pollution they produce and the congestion they cause, according to legislation approved by the Transport Committee. The Eurovignette scheme has been proposed, whereby new charges would be potentially levied against things such as noise and air pollution and also weight related damages from the lorries themselves.