In 2006, the US trucking industry employed 1.8 million drivers of heavy trucks. There is a shortage of willing trained long-distance truck drivers. Part of the reason for this is the economic fallout from deregulation of the trucking industry. Michael H. Belzer, associate professor, in the economics department at Wayne State University and co-author of Sweatshops on Wheels: Winners and Losers in Trucking Deregulation, argues that low pay, bad working conditions and unsafe conditions have been a direct result of deregulation. The book cites poor working conditions and an unfair pay system as responsible for high annual employee turnover in the industry. In 2018, in the US, 5,096 large trucks and buses were involved in fatal crashes: The number of large trucks involved in fatal crashes is 4,862, The number of large trucks involved in injury crashes is 112,000, The number of large trucks involved in property damage only crashes is 414,000. Environmental effects Like cars, trucks contribute to air, noise, and water pollution. Unlike cars, , most trucks run on diesel, and diesel exhaust is especially dangerous for health. Some countries have different vehicle emission standards for trucks and cars. NOx and particulates emitted by trucks are very dangerous to health, causing thousands of early deaths annually in the US alone. As older trucks are usually the worst, many cities have banned 20th century trucks. Air pollution also threatens professional truck drivers. Over a quarter of global transport emissions are from road freight, in 2021 over 1700 million tonnes from medium and heavy trucks, so many countries are further restricting truck emissions to help limit climate change. Many environmental organizations favor laws and incentives to encourage the switch from road to rail, especially in Europe. Several countries have pledged that 30% of sales of trucks and buses will be zero emission by 2030. With respect to noise pollution, trucks emit considerably higher sound levels at all speeds compared to typical cars; 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