The influence of subway station design on noise levels.

OBJECTIVES/HYPOTHESIS: To investigate the impact of subway station design on platform noise levels.

STUDY DESIGN

Observational.

METHODS

Continuous A-weighted decibel (dBA) sound levels were recorded in 20 New York City subway stations, where trains entered on either a straight track or curved track in 10 stations each. Equivalent continuous noise levels (L ) at various locations on the boarding platform (inbound end, midplatform, and outbound end) during train entry and exit were compared between the straight and curved stations in broadband as well as narrow one-third octave bands.

RESULTS

Overall, curved stations trended louder than straight stations, although the difference in broadband L did not reach statistical significance (curve, 83.4 dBA; straight, 82.6 dBA; P = .054). Noise levels were significantly louder at the inbound end of the platform during train entry (inbound, 89.7 dBA; mid, 85.5 dBA; outbound, 78.7 dBA; P < .001) and at the outbound end during train exit (inbound, 79.7 dBA; mid, 85.3 dBA; outbound, 89.1 dBA; P < .001). Narrow band analysis showed that curved stations were significantly louder than straight stations at 100 Hz and high frequencies from 8 to 20 kHz. Peak impact levels ranged from 104 to 121 dBA.

CONCLUSIONS

Curved stations have a different noise profile compared to straight stations and are significantly louder than straight stations at high frequencies. Designing stations with straight tracks within the platform can help reduce commuter noise exposure.

LEVEL OF EVIDENCE

NA Laryngoscope, 127:1169-1174, 2017.