title: Noise exposure and convertible cars.
abstract: OBJECTIVE
  To investigate whether drivers of convertible cars are exposed to excessive noise levels.
  
  
  METHODS
  Prospective.
  
  
  METHODS
  Data were collected along a main United Kingdom highway.
  
  
  METHODS
  Seven cars were included within the study, encompassing a range in cost, power, and comfort. A calibrated, integrating noise meter was used to measure average noise levels (Leq dB) and peak levels (Lmax dB) encountered in the region of the driver's roadside ear with the convertible roof lowered. Readings were recorded at speeds of 50, 60, and 70 mph with the windows lowered and also at 70 mph with the windows raised.
  
  
  RESULTS
  Noise levels for all testing conditions had a range for Leq of 82 dB to 92 dB, whereas the maximum Lmax level noted for articulated lorries was 99 dB.
  
  
  CONCLUSIONS
  A minimal trend toward increasing noise levels with speed was noted for the speeds tested. A statistically significant difference in noise reduction was found by raising the car windows. Although average levels were noted to be above the 85 dB criterion level legislated by some organizations, the length and frequency of most car journeys with the convertible roof lowered is unlikely to significantly increase the noise exposure risk of most individuals. Future studies may be able to evaluate whether a temporary threshold shift phenomenon may occur.
authors.affiliation: Worcestershire Royal Hospital, Charles Hastings Way, Worcester, United Kingdom. phil.michael@doctors.org.uk
authors.forename: Philip
authors.initials: P
authors.lastname: Michael
authors.forename: Neil
authors.initials: N
authors.lastname: Opie
authors.forename: Michael
authors.initials: M
authors.lastname: Smith
mesh_terms: D001309:Auditory Threshold; D001336:Automobiles; D004867:Equipment Design; D006317:Hearing Loss, Noise-Induced / Q000209:etiology; D006801:Humans; D009624:Noise, Transportation; D011446:Prospective Studies; D012984:Software; D018709:Statistics, Nonparametric