Article first appeared on October 12, 2015 in: Including symbols in license plates improves recall
Including symbols in license plates improves
October 12, 2015
NEW ORLEANS – Substituting a symbol for a number in a sixcharacter license plate was found to
significantly improve shortterm recollection as compared to conventional alphanumericonly designs,
according to a presenter here at an American Academy of Optometrysponsored press conference.
Alan L. Lewis, OD, PhD, FAAO, and colleagues from the New England College of Optometry
evaluated the EZID, a proposed license plate design that uses a heart, star, triangle or square in place
of a number or letter in a sixcharacter license plate, as a method for making license plates more
At the press conference, Lewis shared the impetus for the proposed design change.
“A murder occurred in Massachusetts where a lot of people saw the car, but couldn’t
identify the license plate,” he said.
The researchers randomly selected 10 sixcharacter Massachusetts license plates from a
sample of cars. Five of the plates were modified to replace one of the two middle
characters with a symbol.
Twentyeight subjects sat 1.5 meters away from a monitor, and 10 different plates were displayed for 3
seconds each, Lewis explained.
“A distractor photo of a president was shown to get them to think about something else, then they were
asked to repeat the license plate,” he said.
“Fortythree percent of all plates were correctly identified,” Lewis said. “Sixtyone percent identified
more plates with symbols. Only 7% of plates with alphanumerics were correctly identified.”
He said that 53% of plates containing symbols and 33% of plates containing only alphanumerics were
completely correctly identified.
“Ninetysix percent of all symbols were correctly recalled,” Lewis said, “and they were always in the
right position. This is a great ability to reduce the gamut of potential vehicles with those plates.”
He concluded: “We believe the inclusion of symbols in a sixcharacter license plate increases the recall
of a complete license number. We are moving ahead to try to convince legislators to change license
plate design.” – by Nancy Hemphill, ELS, FAAO
Disclosure: No products were mentioned that would require financial disclosure.