Data from published noise-annoyance surveys are related to a common measure of noise exposure Ldn. The results provide means for predicting the annoyance (experienced by percentages of people of normal and of supersensitivity) attributable to noise from aircraft and from street and road traffic. Correlations of 0.90 to 0.95 are found between Ldn and percentages of people annoyed by aircraft noise when low, moderate, and higher levels of annoyance are measured for both a broad range (35 dB) and a restricted range (20 dB) of Ldn. Noise from urban street and road traffic is shown to cause less annoyance than the noise from aircrafts when both have the same Ldn as typically measured or estimated for outdoors. The difference, equivalent to a difference of about 10 dB in Ldn, is attributed to acoustical factors that diminish in-and-around-the-home noise dosages from ground vehicular traffic compared to dosages from aircraft operations. Generalized functions showing degrees of annoyance and percentages of U.S. urban population exposed to effective levels of Ldn for aircraft noise and for street and road traffic noise are presented. It is shown that an earlier analysis by Schultz [’’Synthesis of social surveys on noise annoyance,’’ J. Acoust. Soc. Am. 64, 377–405 (1978)] significantly underestimates the annoyance associated with aircraft noise and significantly overestimates the percentages of the U.S. population to be exposed to effective levels of noise from vehicles of transportation.