Sun Glare Impacts on Freeway
Congestion: Geometric Model and Empirical Analysis
Journal of Transportation Engineering,
vol. 138, no.10, pp. 1196-1204.
In this paper, a geometric model for predicting locations and times where
sun glare has the potential to affect drivers on roadways was developed. Existing or prospective highway
alignments can be considered. The
method includes appropriate geometric models of the roadway alignment,
astronomical computations for the relative position of the sun in the sky, and
corrections for atmospheric refraction.
Novel graphical tools were introduced to indicate the results of the
model, which include sets of time and location where sun glare should be
expected. The hypothesis that sun
glare has an effect on congestion was tested by comparing real speed data from
locations and times at which the geometric model indicates the presence of sun
glare with those at which it does not.
Sun glare is shown to have a statistically significant impact on mean
traffic speeds.