ITE Journal January 2018 - 46

Järlström (2014) disagreed with the classification of four state laws
(Connecticut, Louisiana, Tennessee, and West Virginia) in NCHRP
Report 731.18 It was suggested that the yellow law classification for these
states should be changed from Class 2 to Class 1 for three states and
the Connecticut State law categorization should be changed from Class
3 to Class 1. The difference in classifications likely results from subtle
differences in the language included in the brief legal definitions. If the
word "warned" appeared in the definition Järlström argued the law should
be classified as permissive. Two knowledgeable transportation professionals could review the same definitions and arrive at alternative conclusions
as to the correct interpretation. Regardless, a challenge for drivers is
introduced when they cross state boundaries and in doing so become
bound by a yellow light law with distinctly different requirements.

clear the intersection. There are 19 states that include this language
in their driver training manuals (Figure 3).

Driving Manual Language

Situation 3: Accelerating to beat the light is illegal. The vehicle
typically is not close enough to the stop line to clear the intersection
at the current approach speed, so the driver accelerates. Nine states
include this language in their driver training manuals (Figure 4).

State Departments of Motor Vehicles publish driver training manuals
(DTM) which include text and figures used to explain driving laws.
There is a section in each of the 50 DTMs that describes the meaning
and/or appropriate driver response to CY. This section of text was
transcribed into table format, and each research team member
independently reviewed the text to classify the possible scenarios
described, and which state driver training manuals they were described
in. Through discussions, the individual rankings were compared until
a consensus was reached. Ultimately, the language used to describe
what drivers should do in response to a steady CY includes one of four
possible situations. These four situations are entirely derived from the
DTM language in all 50 states, however 6 state driver training manuals
do not provide direct instruction to drivers about how to respond to
the CY, and therefore cannot be classified.
Situation 1: The vehicle should avoid entering the intersection
during the CY. The vehicle is far enough away from the stop line
at the onset of the CY that the driver is able to decelerate and
stop safely at the stop line. There are 40 states which include this
language in their driver training manuals (Figure 2).

Figure 3. Nineteen states include situation 2 in their driver training manuals.

Figure 4. Nine states include situation 3 in their driver training manuals.
Situation 4: The vehicle should continue through the intersection if the light turns yellow while in the intersection. If the vehicle
is in the intersection at the onset of the CY, the driver should just
continue through the intersection. There are 21 states that include
this language in their driver training manuals (Figure 5).

Figure 2. Forty states include situation 1 in their driver training manuals.
Situation 2: If the vehicle is too close to stop safely, the vehicle
should continue through the intersection with care. The vehicle is
close enough to the stop line at the onset of the CY that drivers can
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Figure 5. Twenty-one states include situation 4 in their driver training manuals.
Much of the previous research on driver behavior at the CY onset
has focused on the lead vehicle. One seemingly unanswered question

Table of Contents for the Digital Edition of ITE Journal January 2018