A field study of effects of road traffic and railway noise on polysomnographic sleep parameters

The aim of this study was to explore and compare the effect of noise from railway and road traffic on sleep in subjects habitually exposed to nocturnal noise. Forty young and middle aged healthy subjects were studied with polysomnography (PSG) during two consecutive nights in their own bedroom. Noise measurements and recordings were conducted concurrently outside of the bedroom fac?ade as well as inside the bedroom of each participant. Different noise exposure parameters were calculated (L(p,A,eq,night), L(p,A,Fmax,night), and L(AF5,night)) and analyzed in relation to whole-night sleep parameters. The group exposed to railway noise had significantly less Rapid eye movement, (REM) sleep than the group exposed to road traffic noise. A significant association was found between the maximum level (L(p,A,Fmax,night)) of railway noise and time spent in REM sleep. REM sleep was significantly shorter in the group exposed to at least a single railway noise event above 50 dB inside the bedroom. These results, obtained in an ecological valid setting, support previous laboratory findings that railway noise has a stronger impact than road traffic noise on physiological parameters during sleep, and that the maximum noise level is an important predictor of noise effects on sleep assessed by PSG, at least for railway noise.     

Annoyance due to single and combined sound exposure from railway and road traffic

Environmental noise is a growing and well recognized health problem. However, in many cases people are exposed not to a single noise source-for example, road, railway, or aircraft noise-but to a combination of noise exposures and there is only limited knowledge of the effects on health of exposure to combined noise sources. A socio-acoustic survey among 1953 persons aged 18-75 years was conducted in residential areas exposed to railway and road traffic noise with sound levels ranging from L(Aeq,24h) 45-72 dB in a municipality east of Gothenburg, Sweden. The objectives were to assess various adverse health effects, including annoyance, and to elucidate the impact of exposure to single and combined noise sources. In areas exposed to both railway and road traffic, the proportion annoyed by the total traffic sound environment (total annoyance) was significantly higher than in areas with one dominant noise source (rail or road traffic) with the same total sound exposure (L(Aeq,24h,tot)). This interaction effect was significant from 59 dB and increased gradually with higher sound levels. Effects of the total sound exposure should be considered in risk assessments and in noise mitigation activities.     

Annoyance and disturbance of daily activities from road traffic noise in Canada

This study evaluated road traffic noise annoyance in Canada in relation to activity interference, subject concerns about noise and self-reported distance to a major road. Random digit dialing was employed to survey a representative sample of 2565 Canadians 15 years of age and older. Respondents highly annoyed by traffic noise were significantly more likely to perceive annoyance to negatively impact health, live closer to a heavily traveled road and report that traffic noise often interfered with daily activities. Sex, age, education level, community size and province had statistically significant associations with traffic noise annoyance. High noise annoyance consistently correlated with frequent interference of activities. Reducing noise at night (10 pm-7 am) was more important than during the rest of the day.     

Subjective response to road traffic noise

A study consisting of acoustic measurements at fourteen sites in the London area and 1200 interviews dealing with the effects of the noise conditions prevailing at each of these sites has been carried out with the object of developing acceptability criteria for traffic noise from roads in residential areas. Dissatisfaction with the noise conditions, as expressed by residents at each of these sites, was related to sound levels in such a way that it was possible to predict the median level of dissatisfaction at each site by the use of a measure taking into account the mean sound levels exceeded for 90 and 10 % of the sampling periods throughout a whole day, which it is proposed to call the Traffic Noise Index (T.N.I.). Predictions made on the basis of either 10 or 90 % levels alone were considerably less accurate than those made on the basis of the combined measure. Individual dissatisfaction scores correlated poorly with physical measures. This finding is believed to be the result of wide individual differences in susceptibility to and experience of noise, as well as in patterns of living likely to be disturbed by noise. Attempts to allow for these factors were unsuccessful. Disturbance of various activities was shown to be related to noise levels and the increasing extent of this effect with worsening of noise conditions was used to validate the scale of dissatisfaction.     

Sleep disturbance effects of traffic noise—A laboratory study on after effects

Body movements during sleep and subjective sleep quality, as well as mood and performance were investigated after exposure to intermittent and continuous traffic noise during the night. In a first experiment, six young subjects slept in the laboratory for five nights; in a second experiment 12 subjects slept six consecutive nights in the laboratory. A good dose-response relationship was obtained between intermittent noise and subjective sleep quality: i.e., the higher the noise level, the poorer the sleep quality. A similar dose-response relationship was found for body movements immediately following noise peaks during nights with intermittent noise. Performance and mood tended to be worse after intermittent noise. However, these effects did not increase with an increase in noise levels. Compared with intermittent noise, continuous noise had a significantly smaller effect on sleep quality. Mood and performance were not worse after continuous noise. The results suggest that increased attention should be paid to peak noise levels when standards for nocturnal noise are set.     

The effect of road traffic noise on house prices

Existing U.K. legislation compensates home owners for house price depreciation due to increases in environmental noise caused by public works. Several previous studies have been attempted to show the effects of noise on house prices but have been inconclusive because of a failure to meet basic requirements for a rigorous analysis. In this paper these requirements are discussed and a study designed to fulfil them based on the southern Ontario housing market is described. Data on 2277 individual housing transactions at 51 sites close to major roadways were analyzed to determine the effects of road traffic noise on house prices. Results show that noise has a significant and consistent effect equal to approximately $254 per decibel depreciation at the arterial sites examined and $312 per decibel depreciation at the expressway sites.     

Subjective effects of traffic noise exposure: reliability and seasonal effects

Repeated interview surveys were made in suburban residential areas of London. At six selected sites, four sets of interviews were conducted at different times of year and at a further two sites two sets of interviews were conducted during summer months. At all sites traffic noise levels were measured over 24 hours at each interview phase with a microphone 1 m from the dwelling facade at first floor level. Seasonal weather data were also collected. In the course of the repeated interviews the initial sample of 364 respondents was reduced to 222. The questionnaire included two types of noise nuisance scale, questions bearing on the typicality of road traffic conditions, and on the opening and closing of windows. The results confirm others already reported but in addition, show that if annoyance scores are averaged over repeated occasions a highly significant increase in reliability is obtained, and the proportion of score variance accounted for by noise increases significantly. No evidence was found of seasonal changes in traffic noise levels and annoyance scores did not vary significantly despite significant differences in the proportion of windows open at different times of the year.     

Nocturnal road traffic noise assessment and sleep research: The usefulness of different timeframes and in- and outdoor noise measurements

In this paper, we investigated the procedure of noise assessment in the study of nocturnal noise exposure during sleep in the home situation. The use of two different timeframes (fixed from 11 PM to 07 AM versus personal “Time in Bed” period) was explored as well as the relation between indoor and outdoor noise levels and between the actual and estimated noise levels. Noise recordings were performed inside and outside the bedroom of 24 subjects living in high density road traffic noise areas in the Brussels’ Capital Region during seven consecutive days. Indoor and outdoor noise indicators L_Aeq, L_Amax and individual noise events were analysed. Subjects completed a daily sleep log in which the Time in Bed period was assessed. The results indicate that, for outdoor noise assessment, the use of an average L_Aeq might not be sufficient to reflect well the noise levels during the sleep period. For indoor measurements, significant differences were found in the comparison between both timeframes (L_Aeq: T = 16; p < .001). Considering the relation between indoor and outdoor measurements, low correlations (r = .49; p < .001) were found even when the location of the bedroom as a mediating factor was accounted for (street side; r = .52; p < .001). Therefore, from our study, caution is needed when relying on outdoor noise measurements for the evaluation of sleep disturbances. Furthermore, one needs to be aware of the weak correspondence between indoor and outdoor noise levels in the discussion of what a harmonized noise indicator for the evaluation of noise exposure and sleep disturbances should consist of.     

Practical guidance for risk assessment of traffic noise effects on sleep

Environmental noise disturbs sleep and may impair well-being, performance and health. The European Union Directive 2002/49/EC (END) requires member states to generate noise maps and action plans to mitigate traffic noise effects on the population. However, practical guidance for the generation of action plans, i.e. for assessing the effects of traffic noise on sleep, is missing. Based on the current literature, we provide guidance on hazard identification, exposure assessment, exposure-response relationships and risk estimation: there is currently no consensus on both exposure and outcome variables that describe traffic noise effects on sleep most adequately. END suggests the equivalent noise level L_night as the primary exposure variable, and our own simulations of single nights with up to 200 noise events based on a field study on the effects of aircraft noise on sleep support using expert consensus L_night ranges (<30, 30-40, 40-55, >55 dB) for risk assessment. However, the precision of risk assessment may be considerably improved by adding information on the number of noise events contributing to L_night. The calculation of L_night should be extended to the shoulder hours of the day if traffic is busy during these periods. More data are needed on the combined effects of different traffic modes.     

Responses to an increase in road traffic noise

Results are presented of a small longitudinal study of community response to road traffic noise following an increase in traffic along a residential street. A total of 20 respondents were surveyed and they showed no evidence of adaptation to the increased noise over the period between 7 and 19 months after the increase in traffic. Respondents' assessments of annoyance with the before-change conditions, made retrospectively after the change, were quite different from the assessments of annoyance that they made before the change occurred, though most of this difference was contributed by 8 of the 20 respondents. This small data set, when put together with other evidence on response to changed conditions, suggests that response bias is present in steady state assessments of annoyance and of a magnitude which would significantly affect the validity of self-reports of annoyance.     

The differing annoyance levels of rail and road traffic noise

The results of a study on the relative annoyance by rail or road traffic noise in urban and rural areas are reported. Fourteen areas with rail and road traffic noise with differing levels of loudness (L_eq) were investigated. The annoyance was assessed by means of a questionnaire. The analysis of the relationship between annoyance and L_eq—performed separately for rail and road traffic noise—shows that the same amount of annoyance is reached for railway traffic noise at L_eq levels 4–5 dB(A) higher than for road traffic noise (railway/traffic noise “bonus”). The estimation for the difference values vary for the different variables of annoyance. Furthermore, the difference levels tend to be higher in urban than in rural areas.     

The evaluation of noise from freely flowing road traffic

Roadside surveys of the noise emitted by freely flowing traffic have been made on sites ranging from motorways to urban roads. Sites were generally unobstructed but a few tests were made in places with buildings adjacent to the roadway. The survey also included measurements on two sites involving road gradients.The results provide an indication of present-day traffic noise conditions against which future comparisons may be made and also show how basic variables such as traffic density, speed and composition, and distance from the roadside affect the observed patterns of noise.Agreement between the experimental data and a theoretical analysis of simplified traffic flow forms the basis of a method for predicting the median sound level produced under any given set of traffic conditions. The reliability of the method, provided that due allowance is made for possible ground attenuation effects, is demonstrated using the results of the survey.Finally by a simple extension of the prediction method it becomes possible to take both noise level and duration factors into account and arrive at a figure for total noise exposure from the same traffic flow data.     

Patterns of behaviour in dwellings exposed to road traffic noise

An inquiry involving a total of 1500 subjects residing in 15 different sites in the conurbations of Lyon and Marseilles was carried out in 1979 with a view to determining the behaviour and attitudes of people with regard to traffic noise. The main purpose of the inquiry was to identify the objective reactions to the traffic noise and to determine how such reactions varied with the noise level, with account taken of the socio-economic characteristics of the subjects (age, income, owner occupier or tenant, etc.). The 08.00–20.00 hour L_eq noise level was measured or calculated for each of the dwellings included in the inquiry. The 00.00–05.00 and 20.00–24.00 hour L_eq values were also derived for each case and a total of nearly 20 000 different noise levels were involved in the analysis of the data for this inquiry. On considering the completed questionaires it was found that the annoyance experienced during the day was more closely correlated with the noise level (r = 0·64) than had been the case with the results of previous studies. In addition to showing how traffic noise can interfere with activities and lead, for example, to the closing of windows to shut out the noise, the inquiry yielded information on the way in which activities affected by noise are transferred to quieter rooms, on the extent to which individual dwellings are sound proofed, on the extent to which occupants are likely to move to another dwelling in order to escape from the noise and finally on some aspects of the effects of noise on health and sleep. Thus it appears that a daytime L_eq value of more than 65 dB(A) gives rise to what can be regarded as forced behavioural responses to the extent that there are significant changes in the normal way of life of the people concerned and such responses give an indication of the magnitude of the social costs that can be attributed to the undesirable effects of traffic noise.     

Comparison between train noise and road noise annoyance during sleep

Sleep disturbance by train and road noises was studied through in situ physiological recordings on two groups of people submitted to both types of exposure. At different sites acoustical parameters do not influence sleep in the same way. In a quiet place, emergence is an important factor of disturbance, but in a noisy place, noise duration and peak level are acting with interaction to disturb sleep.     

Pressure Leq and multiple noise sources: A comparison of exposure-response relationships for railway noise and road traffic noise

Exposure-response relationships vary with different noise sources when conventional L_eq is used as the noise exposure measure. Further, reported annoyance to multiple noise source environments can be higher than predicted by conventional L_eq. Pressure L_eq is proposed as a superior unified noise index and some evidence is presented in support of this proposal.     

Some effects of tyre tread and road surface on road noise

A complex dynamic system can often be modeled in terms of coupled basic dynamic systems. A basic dynamic system is a system whose response can be specified in terms of a scalar quantity. A general formalism, dealing with the response of a complex dynamic system, is developed. The formalism spans several previous formalisms and encompasses new material that has not been previously considered, e.g., direct couplings between the ribs on a panel. The format is chosen so that it provides for consideration of elements of the statistical energy analysis (SEA). Thus, for example, the expression for the frequency spectral power flow between two basic dynamic systems is derived and cast in a modal form. In particular, various conditions and approximations under which cross modal terms vanish in the expression are specified and interpreted. Modal densities are defined and used to obtain further reductions in the expression for the power flow between two multimodal basic dynamic systems.