Wayne H. Warren Jr.
8001 Brett Place
Greenbelt, Maryland 20770-3001
Marilyn J. Praisner Safe and Earth-Friendly Roadway Act
March 10, 2011
I wish to thank the Chairman and members of the committee for the opportunity to
comment on the subject legislation, Maryland HB 906 (2011 Session).
Although there are many issues that could be discussed in relation to light pollution in
general, I wish to comment only on what I believe to be the principal reasons for
controlling light spillage on Maryland highways. The text of HB 906 mentions some of
the adverse effects of poor lighting on human and animal health and other environmental
issues, so I don’t want to take space here to discuss those topics. I am also concerned, as
a professional astronomer and educator, about the loss of dark skies in our state and all
over the U.S., but I believe the important issues here are the effects of glare, light
trespass, and excessive costs of too much light.
The subject of glare is often raised when discussing lighting issues. Glare is always a bad
thing. Light spillage produces glare and glare reduces nighttime visibility. During
adverse weather conditions such as rain and snow, glare produces light diffraction and
interference effects that contribute to poor visibility. Well designed luminaires that direct
the light toward the ground where it is needed do not produce glare and that is always a
good thing. It is well documented that unshielded hot light sources cause the pupil to
constrict, leading to the perception of faint ground lighting and bad, contrasty road
conditions. Glare is an especial problem for the elderly with cataracts, leading to light
scatter and flare, thus making it particularly difficult for them to drive at night.
The other important consideration is the excessive costs of too much light. Although the
bill states that initial costs will be increased and that eventual savings cannot be
predicted at this time, it has been the experience of lighting conservationists and
professionals that efficient lighting always decreases costs in the long run. Numerous
studies carried out by the International Dark-Sky Association have shown that when
lighting is more efficient, lower wattages can be used to produce the same illumination
where it is needed. It is a logical conclusion that decreased power requirements will
result in considerable savings over time. It is estimated that billions of dollars are wasted
each year in the United States alone to light the sky and places on the ground where light
is neither needed nor desired. This so-called “light trespass” is another negative
consequence of poor lighting and a source of glare.
I hope that the negative consequences of poor and excessive lighting will be seriously
considered by the committee and that this legislation will become law. This can be the
beginning of eventual lighting ordinances that could save our state millions of dollars
each year while at the same time improving the nighttime environment for our citizens.
Thank you once again for the opportunity to voice my opinions on these issues.
Dr. Wayne H. Warren Jr.
PHI Applied Physical Sciences
8001 Brett Place
Greenbelt MD 20770-3001
301-474-0814 (V)
301-441-3690 (F)
301-518-5754 (C)
Assistant Professor of Physics and Astronomy
Department of Physics, Astronomy, and Geosciences
Towson University
8000 York Road
Towson MD 21552
410-704-4729 (V)
410-704-3511 (F)
Associate Professor of Astronomy
Department of Physical Sciences and Environmental Management
University of Maryland University College
3501 E University Boulevard
Adelphi MD 20783
WWarren@umuc.edu