How does train horn noise compare with other noise sources?
Federal Railroad Administration
U.S. Department of Transportation

Train horns are installed on locomotives to warn motorists or pedestrians of an approaching train at a highway-rail grade crossing. In many geographic locations, and during much of the year, motor vehicles operate with windows rolled up, air conditioning systems and radios in use. Therefore, audible warning signals must be sufficiently loud to be perceived. Unfortunately, the locomotive horn can significantly disturb those living or working near highway-rail grade crossings. A comparison of general noise levels from various commonly-experienced noise sources in our environment as well as typical ambient noise levels in the last column are shown in Figure 1. For instance, the noise resulting from the sounding of train horns has a similar impact to that of low flying aircraft and emergency vehicle sirens.

How do people react to noise from train horns?

Excessive noise has the potential to disrupt routine activities, which can affect the overall quality of life, especially in residential areas. In general, most residents become highly irritated/annoyed when noise interferes significantly with activities such as sleep, interpersonal or telephonic conversation, noise-sensitive work, watching television or listening to the radio or recorded music. In addition, some land uses, such as outdoor concert or pavilions or recreational sports venues , are inherently incompatible with high noise levels.

Human annoyance to noise in the environment has been investigated and approximate exposure-response relationships have been quantified by the Environmental Protection Agency (EPA). The selection of noise descriptors by FRA is largely based upon this EPA work. Beginning in the 1970s, EPA undertook a number of research and synthesis studies relating to community noise of all types. Results of these studies have been widely published and discussed, and are regularly cited by many professionals in the acoustics field. The basic conclusions of these studies have been adopted by the Federal Interagency Committee on Noise, the Department of Housing and Urban Development (HUD), the American National Standards Institute, and in some cases by international organizations and entities. Conclusions from this seminal EPA work remain scientifically valid to this day.

In a large number of community attitudinal surveys, transportation noise has been ranked among the most significant causes of community dissatisfaction in census surveys. A synthesis of many such surveys on annoyance appears in Figure 3. Different neighborhood noise exposures are plotted horizontally. The percentage of people who are highly annoyedby their particular level of neighborhood noise is plotted vertically. As shown in the figure, at 45 Ldn, the level of high annoyance in a community averages 0 percent. At 60 Ldn, approximately 10 percent of respondents reported being highly annoyed, while at 85 Ldn, the proportion of those being highly annoyed increases quite rapidly to approximately 70 percent. The scatter about the synthesis line is due to variation from person to person, community to community, and to slight differences among the various surveys.

Read more on train noise at the Federal Rail Authority >