Research On The Audiovisual Influences On Traffic Noise Evaluation In Commercial Pedestrian Spaces Adjacent To Carriageways

A pleasant urban street environment is vital to enhancing the appearance of the city and the quality of the urban environment.Pedestrian streets,represented by outdoor commercial streets,are an important part of urban public space and have an unquantifiable positive impact on the presentation of the city’s image,the shaping of a livable environment and economic development.Therefore,under the advocacy and practice of shifting from "car-oriented" to "people-oriented" streets,it is important to enhance the comfort of pedestrian spaces on the street.Traffic noise,as a major source of urban noise,has seriously affected people’s physical and mental health and quality of life,and commercial pedestrian spaces are inevitably disturbed and affected by traffic noise.However,the evaluation of the sound environment of commercial pedestrian spaces near carriageways at home and abroad is still very limited.Based on this,this paper considers the visual and auditory factors as a whole,examines the evaluation of the sound environment of street-level commercial pedestrian spaces and its influencing factors from the perspective of acoustic comfort,and proposes corresponding design and control guidelines for the visual and auditory factors in urban design at the medium and micro levels from a proximate perspective.This paper selects five characteristic commercial streets in Dalian as the research object Firstly,after a series of simulation parameters were obtained,the traffic noise of the five commercial streets and their neighbourhoods was simulated by Cadna/A noise simulation software at four different times during the daytime on weekdays to get a preliminary understanding of the spatial distribution characteristics and objective influencing factors of traffic noise of each commercial street.An on-site interview questionnaire was then used to investigate the attitudes of current users of street pedestrian spaces with regard to the evaluation of acoustic comfort and the perceived characteristics of the visual environment,while a sound level meter was used to measure the ambient sound levels on site.By analysing the collected first-hand subjective and objective data with the help of SPSS data analysis software,it was found that the visual environment perception elements of commercial building design elements,spatial scale perception elements,objective ambient sound pressure level and sound source composition elements all have significant effects on the users’ acoustic comfort evaluation.By constructing a regression model,the thresholds of the different ambient sound levels corresponding to the rating of "comfortable" in a real commercial pedestrian space adjacent to carriageways were obtained.In order to further investigate the audiovisual factors influencing the evaluation of traffic acoustic comfort commercial pedestrian spaces adjacent to carriageways,In this paper,three streetscape components(architectural style,openness of building layout and richness of external additions to buildings)were selected as visual stimuli based on the findings of fieldwork,and each was combined with a traffic sound source with sound pressure levels of 50 d B(A),55 d B(A),60 d B(A),65 d B(A)and 70 d B(A)to conduct an audiovisual experiment in a semi-anechoic laboratory in this paper.Analysis of the results of the experimental questionnaire revealed that traffic sound pressure levels have a significant negative correlation with traffic acoustic comfort,and the degree of influence of each streetscape component factor varies for different traffic sound pressure levels.This paper discusses this separately.Secondly,a regression model was constructed for each of the three streetscape composition factors to obtain the threshold traffic sound pressure level when the traffic acoustic comfort level for each factor was rated as "average(neither comfortable nor uncomfortable)".The findings can be used as a reference for the streetscape of commercial pedestrian spaces adjacent to carriageways at different traffic sound pressure levels.This study finally focuses on proposing guidelines for the design and control of audiovisual influences in commercial pedestrian spaces adjacent to carriageways optimized for traffic acoustic comfort evaluation.Firstly,the corresponding guidelines are proposed on the basis of the findings of the field research and laboratory studies,and then an example of the design of a commercial pedestrian space adjacent to carriageways with optimised traffic and acoustic comfort evaluation is carried out using the Haixian street in Yanchang New District from the field research,with a view to providing ideas for urban design practice at the medium and micro levels from a proximate perspective.