**ASSESSMENT OF ADVANCED WARNING SIGNS FOR**

**FLAGGING OPERATIONS**

Steven L. Jones, Jr.

Assistant Professor

Department of Civil and Environmental Engineering

University of Alabama at Birmingham

120 Hoehn Building, Room 210B

1075 13^th^ Street South

Birmingham, AL 35294-4440

T: 205.934.8462

F: 205.934.9855

Benjamin H. Cottrell, Jr.

# Senior Research Scientist

Virginia Transportation Research Council

530 Edgemont Road

Charlottesville, VA 22903-2454

Telephone: (804) 293-1932

Facsimile: (804) 293-1990

[Ben.Cottrell@VirginiaDOT.org](mailto:CottrellBH@vdot.state.va.us)

**ABSTRACT**

The Virginia Department of Transportation (VDOT) and several other state
departments of transportation have expressed interest in modifying the
advanced warning sign for work zone flagging operations. The advanced
warning sign is intended to alert drivers to the presence of flaggers
and to prepare drivers to stop (if necessary) prior to reaching work
zone operations. The current or existing flagger sign depicts a symbol
of a worker holding a flag; the proposed sign depicts a worker holding a
STOP/SLOW paddle. The purpose of this research project was to assess and
compare the motoring public's understanding of the existing and proposed
advanced warning signs for work zone flagging operations.

The study consisted of a literature review and a survey of motorists.
Over 3,600 multiple-choice surveys were successfully mailed out to
randomly selected Virginia residents of which 38 percent were returned.
The survey results indicated that the proposed sign was for the most
part understood by Virginia drivers and appeared to be effective at
conveying its message.

**KEY WORDS:** flagger, advance flagger warning sign, flagging, traffic
control device, work zones

**INTRODUCTION AND PROBLEM STATEMENT**

The Virginia Department of Transportation (VDOT) and other state
departments of transportation have expressed interest in modifying the
advanced warning sign for work zone flagging operations. The general
purpose of the advanced warning sign is to alert the motoring public to
potential traffic flow interruptions caused by flaggers directing
traffic in work zones. Specifically, the advanced warning sign is
intended to alert drivers to the presence of flaggers who are ahead and
to prepare the drivers to stop, if necessary, prior to reaching the
flaggers in the work zone operations.

Currently, the advanced warning sign for flagging operations, W20-7a,
displays the silhouette of a highway worker holding a flag. In practice,
however, traffic in most work zones in Virginia is controlled with
STOP/SLOW paddles instead of red flags. The 1993 Part VI of the *Manual
on Uniform Traffic Control Devices* (MUTCD) was revised to state that
"The STOP/SLOW paddle, which gives drivers more positive guidance than
red flags, should be the primary hand-signaling device"([^1]).
Therefore, the STOP/SLOW paddles have been the standard for work zone
traffic control since 1987, following a three-year phasing-in period.

Although the traffic control symbol itself was changed, the applicable
warning sign, W20-7a, was never updated to reflect the change in work
zone traffic control practices. Therefore, it was proposed that the
flagger sign W20-7a should be changed from the current symbol of a
worker holding a flag to one depicting a worker holding a STOP/SLOW
paddle. Examples of the original sign and the proposed W20-7a sign are
presented in Figures 1 a and b, respectively.

In 1987, the Federal Highway Administration (FHWA) conducted a study in
response to a petition to modify the W20-7a sign to display a worker
holding a STOP/SLOW paddle instead of a flag. This FHWA in-house human
factors study indicated that it was difficult for drivers to correctly
identify the meaning of the new

![](media/image1.wmf) ![](media/image2.wmf)

**a. Original W20-7a Sign. b. Proposed W20-7a Sign**

**FIGURE 1 Original and Proposed Advanced Flagger Warning Signs.**

sign ([^2]). The study showed, however, that drivers easily identified
the meaning of the original W20-7a sign. A subsequent 1989 FHWA study
also showed that drivers more readily understood the original W20-7a
sign than the proposed sign showing a man holding a STOP/SLOW paddle
([^3]).

Part of the reason that drivers were unable to correctly interpret the
meaning of the W20-7a sign with the STOP/SLOW paddle may have been the
fact that the paddle was not widely used at the time of the unpublished
1987 FHWA study. The paddle sign has gained acceptance and increased in
usage in work zone traffic control since the previous studies. As a
result, increasing numbers of motorists have been exposed to this new
sign. Therefore, it would be reasonable to assume that this familiarity
will most likely result in more correct interpretations of the proposed
sign's meaning.

There is concern over the continuing discrepancy between what the
motoring public sees on the existing advanced warning signs and the
actual "flagger" they encounter in the work zone. A 1995 human factors
study of older drivers reported as one of its key findings that signs
should use representational rather than abstract symbols ([^4]).
Currently, the depiction of a worker holding a flag rather than a paddle
does not constitute an accurate representation of the traffic situation
encountered by the driver. In addition, continued use of the original
W20-7a sign has resulted in roadway workers in Virginia erroneously
controlling traffic with flags in an attempt to comply with the advanced
warning signs placed throughout the work zone.

**PURPOSE AND SCOPE**

The purpose of this study is to examine the feasibility of modifying the
W20-7a sign to reflect actual work zone conditions by depicting the
STOP/SLOW paddle in lieu of the flag. An assessment and comparison of
the motoring public's understanding of the existing and proposed flagger
signs were made.

**METHODOLOGY**

**Questionnaire Development**

Two survey questionnaires were developed to ascertain motorists'
understanding of both the existing and proposed flagger signs. The
questions used in the current study include close variations on three of
the six questions used in the unpublished 1987 FHWA study. Each
questionnaire contained a color image of the study sign and four study
questions. In addition, the questionnaire included several questions to
elicit demographic information from the respondents. The questionnaires
were administered directly to participants--these face-to-face
assemblies were called sample groups. The majority of questionnaires
were part of a large mail-out survey. The two versions of the
questionnaires contained identical questions, but differed in that those
for the mail-out survey contained multiple-choice answers, while those
administered to the study groups were open-ended to allow respondents to
"write in" their answers. A sample of the multiple choice format
questionnaire for the proposed sign is presented in Figure 2. The
multiple-choice format was chosen for the mail-out survey to enhance
ease and convenience for respondents with the intent of increasing the
response rate. An open-ended format was used for the sample groups to
provide the researchers valuable information as to what extent the
multiple choice format influenced the responses to the mail-out survey.
Prior to conducting the surveys, the questionnaires were pretested with
VTRC employees to determine their effectiveness. The survey was then
tested at a local adult driver's education class.

**Sample Groups**

Particular attention was directed towards assessing the
understandability of the proposed sign among younger and older drivers.
The needs and responses of older drivers to traffic control are
receiving much attention. Older drivers probably would have encountered
many flagging operations over the years, whereas younger drivers most
likely would have encountered few of these while driving. The open-ended
questionnaire with the proposed sign image was administered to 116
students in driver education classes at three local high schools, 43
undergraduate students in an engineering class at the local university,
and 50 older drivers at a local Senior Center.

**Mail-out Survey**

Self-administered survey questionnaires were distributed to a randomly
selected population of Virginia residents. Statistical analysis was
performed to identify the sample size necessary to provide an
appropriate level of confidence in the survey results. Since there was
considerable subjectivity inherent to the survey questions, it was
decided that a +/- 4 percent error in the survey accuracy at the 95
percent confidence level would be acceptable. This condition resulted in
a desired sample size of 600 survey responses. The researchers assumed a
25 percent survey return rate. The assumption was based on conventional
wisdom among VTRC staff of a 10 to 20 percent return rates for mail-out
surveys and the relative ease of the questionnaire used in the current
study. Questionnaires were developed for both the existing and proposed
signs. Therefore, the total number of responses desired was 1,200 (600
for each sign), requiring a target mail-out distribution of
approximately 4,800 questionnaires.

The Virginia Department of Transportation is investigating how well the
public understands some of its roadway signs. By answering the questions
below, you are playing an important role in helping VDOT make Virginia's
roads safer for everyone. Please take a minute and look at the roadway
sign shown below; then answer the questions and return the survey. A
self-addressed, stamped envelope has been provided for your convenience.
Alternatively, feel free to complete the survey online at our website
address,
[http://www.vdot.state.va.us/vtrc/survey/sign2.htm](http://www.vtrc.survey.sign/).
Please return the completed survey by Friday, November 13^th^. Thank you
for your participation and your concern for safer roads in Virginia.

1\) Have you ever seen this sign in Virginia? (check one)

> ![](media/image3.wmf) **** Yes **** No

2\) What do you think the sign means? (check one)

> **** Children present **** Stop ahead

**** Workers ahead **** Slow down

**** Flagger ahead

3\) Where would you expect to see this sign? (check one)

> **** Near a school crossing **** Near road work

**** Near a pedestrian crosswalk **** Near an accident

**** Near a hospital

4\) What would you do if you saw the sign while driving? (check one)

> **** Stop **** Slow down

**** Proceed with caution **** Be prepared to stop

The information below is optional. By completing this information, you
are helping VDOT ensure that we have surveyed a broad range of Virginia
motorists. Please help us make sure that people like yourself are
adequately represented in our study. Thank you.

Personal Information: (check one) Male **** Female ****

Age: Years drivin[g]{.underline}:

Highest Level of Education: (check one)

**** did not complete **** completed **** completed ****
post-graduate

high school high school college education

**FIGURE 2 Sample Survey Questionnaire.**

**Address List Development**

An Internet-based telephone book was used to obtain addresses for 4,800
Virginia residents. This Internet database contains telephone and
address listings from phonebooks throughout Virginia. The website
provides a searchable interface to the listings in the database by last
name, first name, and state. The listings in the database can be
searched by the first letter of the first and last names.

A methodology to randomly select names and addresses from the database
was developed. The method involved the development of a list of random
number pairs. Each of the pairs contained two random numbers between 1
and 26, corresponding to the letters of the alphabet. For example, a
number pair containing 1 and 2 would correspond to the letters A and B.
For this example pair, "A" would be entered as the first letter of the
last name and the "B" would be entered as the first letter of the first
name. The database would then be searched for names and addresses of
Virginia residents with last names beginning with "A" and first names
beginning with the letter "B." For each search, 10 name and address
listings were reported by the Internet search engine. These listings
were then recorded and stored for use in the mail-out survey. A list of
10 names and addresses were obtained for each random number pairs until
4,800 listings had been recorded. The listings were checked for format,
screened for repetition, and printed on mailing labels for distribution
of the survey questionnaires. Screening of the initial addresses
resulted in approximately 300 names and addresses being discarded due to
incompleteness.

**Response Analyses**

A detailed analysis was performed after the sample group surveys were
conducted and a sufficient number of responses to the mail-out surveys
were received. The results of question 1 were tabulated (YES/NO) and
analyzed along with demographic information reported with the surveys.
The following coding from the 1987 unpublished FHWA study was used . The
responses to the substantive survey questions (2, 3, and 4) were coded
as correct, substantially correct, or incorrect where:

-   correct--implies a clear understanding of sign meaning

-   substantially correct--implies a substantive understanding of sign
    meaning

-   incorrect--implies a total lack of understanding of sign meaning.

**RESULTS AND DISCUSSION**

**Mail-out Survey Response Summary**

Approximately 4,500 survey questionnaires were mailed to randomly
selected Virginia residents. Of the 4,500 total surveys mailed out, 813
were returned from the Post Office as a result of an insufficient
address, lack of forwarding address, or other problems with locating the
addressees. Therefore, only about 3,600 questionnaires actually reached
their intended destination. A total of 1,383 questionnaire replies were
received (759 contained the existing sign and 624 depicted the proposed
sign). Only 20 responses were recorded on the survey websites. Using the
number of questionnaires actually delivered, 3,600, the overall return
rate for the mail-out survey was calculated to be approximately 38
percent.

Chi-square analysis was performed on the demographic information to
ensure that the distribution of the various characteristics was the same
for the populations responding to questionnaires pertaining to either
the existing or the proposed sign. The null hypothesis, H~0~, for these
analyses was that the distribution of the characteristics (gender, age,
number of years driving, and education) were the same for both
populations. It is concluded from these results that there is no
statistical difference in the distribution of demographic
characteristics between the two populations (i.e., those viewing the
existing sign and those viewing the proposed sign) for each of the four
characteristics.

**Comparative Analyses**

*Survey Question 1--"Have you ever seen this sign in Virginia?"*

This question was presented in a multiple choice format allowing
respondents to choose either a "YES" or "NO" response. The percentages
of each response are summarized in Figure 3 for both signs. Almost a
quarter of the respondents viewing the existing sign indicated that they
had never seen it. These responses may indicate that the respondents
have not encountered the sign or simply do not recall having done so.
Slightly more than one third of the respondents who viewed the proposed
sign indicated that they had never seen the sign. Approximately 65
percent claimed that they had encountered the proposed sign (although it
has not yet been used in Virginia). A possible interpretation of these
results is that the motorists' responses indicated that there was a
similarity between the existing and proposed signs. Also, respondents
may have perceived the proposed sign as being representative of the use
of STOP/SLOW paddles that they have encountered while driving through
flagging operations throughout Virginia. It is also possible that the 65
percent response may be, in part, a result of the respondents wanting to
give the correct answer or to avoid providing the wrong answer.

![](media/image4.wmf)![](media/image5.wmf)

**FIGURE 3 Distribution of Responses to "Have You Seen This Sign in
Virginia for the Existing and Proposed**

**Signs?"**

*Survey Question 2 -- "What do you think the sign means?"*

Question 2 was intended to elicit how well respondents understood the
meaning of each sign. Responses indicating "flagger ahead" were coded as
correct, while responses of "workers ahead" or "slow down" were coded to
be substantially correct. The substantially correct responses were
interpreted as indicating that the respondent understood that the sign
meant the driver is approaching a work zone and should exercise caution.
The remaining responses, "children present" and "stop ahead," were coded
as incorrect. In conjunction with the unpublished 1987 FHWA study, the
"stop ahead" response was coded as incorrect because it was interpreted
to be a potential safety problem if drivers were influenced to make an
unwarranted stop upon encountering the sign. The percent distributions
of correct, substantially correct, and incorrect responses to question 2
for the existing and proposed signs are shown in Figure 4. These
percentages seem to indicate that the meaning of "flagger ahead" may be
more successfully conveyed by the existing sign depicting the worker
holding the flag than the proposed sign. However, it should also be
mentioned that the presence of the word "flagger" in the list of
possible choices may have biased the survey responses to question 2 for
the existing sign, since it clearly showed a picture of a worker holding
a flag. In other words, respondents may have simply deduced the correct
answer by "matching" the symbol with the term flagger. The rate of
substantially correct responses was similar for both signs. The rate of
incorrect responses, however, was substantially higher for the proposed
sign.

![](media/image6.wmf)![](media/image7.wmf)

**FIGURE 4 Distribution of Answers to "What Do You Think This Sign Means
For the Existing and Proposed**

**Signs?"**

*Survey Question 3 -- "Where would you expect to see this sign?"*

Survey question 3 was administered to ascertain whether or not motorists
correctly anticipated the driving context in which the sign would be
encountered. The percentage distribution of correct responses to this
question for the existing and proposed signs is shown in Figure 5. The
correct response was "near roadwork." There were no specific choices on
the questionnaire that were to be coded as substantially correct.
Although the questionnaire instructed respondents to check only one
answer, some checked more than one in certain instances. Responses that
included the correct answer in addition to an incorrect answer were
coded as substantially correct, with the assumption that the respondent
knew to expect the sign in a work zone, but thought it might also be
used in other applications. Any response not containing "near roadwork"
was coded as incorrect. It is clear from both survey questionnaires that
most motorists correctly associated the signs with roadway work zones.

![](media/image8.wmf)![](media/image9.wmf)

**FIGURE 5 Distribution of Answers to "Where Would You Expect to See
This Sign for the Existing and**

**Proposed Signs?"**

*Survey Question 4 -- "What would you do if you saw the sign while
driving?"*

This was considered the most important question in the survey. The
previous two questions were intended to determine the level of knowledge
motorists possessed about the signs. This allowed respondents to
identify the probable driving action they would take after encountering
each sign. Previous studies have addressed the relative importance of
the driving response to warning signs as being more significant than
their understanding of these signs (*3,*[^5]). The response choices
included one correct answer (be prepared to stop), two substantially
correct answers (slow down and proceed with caution), and one incorrect
answer (stop). The percent distribution of correct, substantially
correct, and incorrect responses are shown in Figure 6 for both signs.
Interestingly, the proposed sign garnered a larger percentage of
responses in both the correct and incorrect categories.

![](media/image10.wmf)![](media/image11.wmf)

**FIGURE 6 Percent Distribution of Answers to "What Would You Do If You
Saw this Sign While Driving?**

**Statistical Analysis**

Statistical analyses were performed on the response data for questions 1
through 4. Chi-square (Χ^2^) analysis was employed to test the null
hypothesis, H~0~, that the distribution of correct, substantially
correct, and incorrect responses was the same for both signs. The null
hypothesis was rejected in the case of all four questions, confirming
the differences apparent in the data.

For question 4 ("What would you do if you saw the sign while driving?")
the data and Χ^2^ results suggested that the rate of correct responses
for the proposed sign was statistically higher than the rate for the
existing sign. A statistical comparison between the rate of correct
responses was then performed The *z* test was then used to test the null
hypothesis, H~0,~ rate of correct responses for the existing and
proposed signs are equal. Use of the *z* test requires the assumption
that the sample population approximates the actual population and is
characterized by a normal distribution. These conditions are generally
satisfied with large sample sizes ([^6]). The difference between these
rates was calculated to be 0.13, indicating a 13 percent higher rate of
correct responses for the proposed sign than the existing sign. The null
hypothesis was rejected, and it was concluded that the rate of correct
responses for the proposed sign was significantly higher than the rate
for the existing sign. The z test was also performed for the incorrect
responses, and for the combined correct and substantially correct
responses. Although the differences for both tests were statistically
significant in favor of the existing sign, at 2.2 percent, it was not
considered practically significant. A difference of at least 5 percent
was assumed practically significant.

**Comparison with Previous Study**

Table 1 displays selected results of both the 1987 FHWA study and this
study for comparison. The results of the survey indicate that the
meaning of the existing flagger sign, as specified by the FHWA, was more
readily identified for the existing sign than the proposed sign that
depicted the worker holding a STOP/SLOW paddle. Based on an
interpretation of the sign as meaning "flagger ahead," the existing sign
garnered 76.5 percent correct responses. Conversely, the proposed sign
was correctly interpreted by 52.3 percent of the survey respondents.
These results are in general agreement with those reported in the
original FHWA study of alternative advanced warning signs for flagging
operations.^3^ When presented with a possible choice of "traffic control
personnel ahead" in lieu of "flagger ahead," 67 percent of the
respondents in an additional survey correctly chose that answer.

Both signs were correctly identified as being associated with road work
operations in the current study. In the 1987 FHWA study, 50 percent of
the responses associated the paddle sign with driving situations other
than roadway work zones or construction activity. More than 30 percent
of the study subjects associated the paddle sign with a school
crossing.^3^ Less than 8 percent of the survey respondents in the
current study incorrectly identified the driving context in which the
proposed paddle sign would be encountered. This suggests that the
increased usage of the STOP/SLOW paddle over the decade since the
original study has made drivers more aware of the paddle and its traffic
control function.

With regard to what the drivers would do when they saw each sign, the
original FHWA study reported that the paddle sign received 36 percent
correct responses and the original flagger sign received 11 percent.^3^
The current study indicates that the correct driving response was
identified for the proposed paddle sign by 79 percent of the
respondents. On the other hand, the correct driving response was
identified for the original flagger sign by 66 percent of the
respondents.

**Table 1. Results of the 1987 FHWA Study and this Study**

Percent of Responses

  ----------------- ----------------- ----------------- -----------------
                                      Existing Sign     Proposed Sign

  Correct Sign      1987 FHWA         100               45
  Meaning                                               

                    This study        76.5              52.3

  Incorrect Sign    1987 FHWA                           50
  Location                                              

                    This study                          17.8

  School Crossing   1987 FHWA                           30

                    This study                          8

  Correct Driver    1987 FHWA         11                36
  Behavior                                              

                    This study        66                79
  ----------------- ----------------- ----------------- -----------------

*Survey Language*

[The Relationship between Sign Meaning and Expected Driving
Behavior]{.underline}

Nearly 30 percent of the responses to question 2 for the proposed sign
were coded as incorrect, indicating that a large percentage of
respondents failed to correctly interpret the sign's meaning. It was not
entirely clear that a multiple-choice response of "stop ahead"
necessarily indicated a lack of understanding of the sign's purpose. It
is unlikely that a driver would actually stop upon encountering an
orange and black advanced warning sign.

The incorrect responses to question 2 on the signs' meaning were
reexamined in more detail. Of the 160 incorrect responses to the
question, 145 (91 percent) were "stop ahead" and 15 (9 percent) were
"children present." The distribution of responses to question 4 among
those individuals providing "stop ahead" responses to question 2 was
summarized. A clear majority of the incorrect "stop ahead" responses to
question 2 (79.6 percent) were accompanied by correct "be prepared to
stop" responses to question 4. Therefore, even though approximately 30
percent of the survey respondents indicated "stop ahead" as their choice
for question 2, the majority of them indicated in the survey that they
would have engaged in the preferred driving response to the proposed
advance warning sign and thus would have prepared themselves to stop.
The combination of these two answers suggest that what the respondents
say they would do is correct, although what they say the sign means is
incorrect.

[Flagger Versus Traffic Control Personnel]{.underline}

If one sees an image of a person holding a flag, there is built-in bias
in favor of a response of flagger ahead when asked about the sign's
meaning. This response may not be provided as readily when an image of a
person holding a paddle is shown. In other words, the existing sign may
have a better chance of being correct because the word flagger is in one
of the multiple-choice answers.

The effect of word choice on the interpretation of the meaning (question
2) was further revealed through a supplemental mail-out survey.
Approximately 200 additional proposed sign questionnaires were mailed
out in the Charlottesville area and 71 completed surveys were returned.
The questionnaires were identical to those used in the original mail-out
survey, with the exception that the possible choice "flagger ahead" was
replaced with the term "traffic control personnel ahead." More than two
thirds of the respondents correctly answered to the revised
questionnaire, where it stated, "traffic control personnel ahead,"
whereas only half responded "flagger ahead" to the original survey.
These results indicate that the motorists were more likely to identify
the symbol as connoting manual traffic control ahead rather than with
the specific term flagger.

[The Influence of the Shape of a Stop Sign]{.underline}

Regardless of the term used to identify work zone traffic control
personnel or the meaning of the sign, a larger percent of the
respondents indicated that they would be prepared to stop in response to
the proposed sign rather than the existing sign (question 4). A possible
reason that the proposed sign received more "be prepared to stop"
responses than the existing sign is tied to the very reason that spurred
the initial resistance to its usage. The unpublished 1987 FHWA study
indicated that drivers interpret the octagonal shaped sign that the
worker is holding as a "STOP" sign (*3).* In actual practice, the paddle
contains a conventional (red and white) "STOP" sign and an orange and
black "SLOW" sign on the reverse side. The fact that drivers may
associate the silhouette as a "STOP" sign suggests that drivers may be
more prepared to stop than if they had encountered a sign depicting a
worker with a flag.

[Concerns with the Choices for the Expected Driving
Response]{.underline}

With respect to the language used in the survey questionnaire, there is
a very subtle difference between the possible choices for the expected
driving response (question 4). "Slow down," "proceed with caution," and
"be prepared to stop" are all very similar responses. A few survey
respondents actually checked all three answers and wrote a comment on
the questionnaire form indicating that they considered the three choices
to be redundant. It is plausible that a driver would slow down and
proceed with caution in preparing themselves to stop.

Consequently, the "be prepared to stop" response is not the only correct
response, but was only designated as such in order to provide a direct
comparison to the unpublished 1987 FHWA study. A 1998 informational
pamphlet on work zone safety published by the FHWA did not mention this
term when describing the existing flagger sign's meaning. The pamphlet
states that: "The symbol means that a flagger is ahead directing traffic
in the work zone. When you see this sign, it's time to be cautious, be
alert to conditions around you, slow down and watch for other directions
or information"([^7]).

*Comparing a Single Sign Versus a Series of Signs in a Work Zone*

In this study, survey data were obtained on a single sign, either for
the existing or the proposed advanced flagger warning sign. This
approach was simple and made the mail-out survey easy. It was also used
to allow a comparison with the unpublished 1987 FHWA study.

In work zones, a series of signs are used to inform and direct
motorists. Figure 7 shows the traffic control layout for a typical
flagging operation on a two-lane road in Virginia ([^8]). The third
sign, "Be Prepared to Stop," informs the motorists of what they are
expected to do. The advanced flagger warning sign warns of a flagger
ahead and identifies the traffic control device that will inform the
motorists whether or not to stop ahead. The survey asked for responses
to a single sign and not the entire context of traffic control in which
the sign would be encountered. It is likely that the answers to the
survey would have been influenced by the series of signs. The "Road Work
Ahead" sign identifies the location or condition that is ahead. The "Be
Prepared to Stop" sign is likely to affect the response regarding what
drivers would do when they see the study sign. (This sign is not
included in the typical layout for flagging operations in the MUTCD.)

## Alternative Points of View

It is acknowledged that an argument in support of the existing sign
could be made based on the survey data. For example, if emphasis were
placed on the results of question 2 on sign meaning, the results would
favor the existing sign. Given that the data may be interpreted in this
manner, the survey results, at a minimum, imply that on balance, the
proposed sign performs as well as the existing sign.

The logical argument about accuracy of the symbol depicted in the sign,
that is, having the advance warning sign display the device that the
flagger will be holding--would favor the proposed sign. Having the
warning sign accurately depict the conditions ahead is desirable. Given
the similarity between the existing and proposed advanced flagger
warning signs, the influence of the series of signs that are
encountered, the issues regarding survey language, and the accuracy of
sign symbols--all of these may be viewed as key reasons for deciding in
favor of the proposed sign.

**CONCLUSIONS**

1.  The proposed sign accurately symbolizes what the motorist will see
    based on previous research.

2.  The correct meaning of the existing sign was clearer to more
    respondents than the proposed sign. Designation of the word
    "flagger" as the only correct interpretation of the sign appeared to
    be biased in favor of the existing sign. Recognizing that the stop
    sign symbol is an important component of the symbol on the proposed
    sign, defining "stop ahead" as an incorrect response was considered
    debatable.

3.  More respondents associated the desired driving behavior with the
    proposed sign than the existing sign. Asking what drivers would do
    when they see a sign is a better measure than asking what the sign
    means.

4.  The proposed sign performs as well as, if not better, than the
    existing sign.

5.  The concept of only one "correct" driving response was questioned
    and the argument was made that the actual number of respondents
    providing suitable descriptions of their probable reactions to the
    proposed sign was greater than 95 percent.

![](media/image12.wmf)

**FIGURE 7 Flagging Operation on Two-Lane Road in Virginia**

**REFERENCES**

[^1]: . Federal Highway Administration. *Standards and Guides for
    Traffic Controls for Street and Highway Construction, Maintenance,
    Utility, and Incident Management Operations. Part IV of the Manual
    on Uniform Traffic Control Devices (MUTCD). 1988 Edition of the
    MUTCD, Revisions 3*. Washington, DC., 1993.

[^2]: . Alicandri, E., Walker, J., and Roberts, K. 1987. *Comparison of
    Flagger Symbols*. Federal Highway Administration. McLean, VA.
    Unpublished data

[^3]: 3\. Paniati, J. Redesign and Evaluation of Selected Work Zone Sign
    Symbols. In *Transportation Research Record* *1213*, TRB, National
    Research Council, Washington, D.C., 1989, pp. 47-55.

[^4]: . Swanson Transportation Consultants, Inc. *Symbol Signing for
    Older Drivers*. Report FHWA-RD-94-069. FHWA, U.S. Department of
    Transportation, 1997.

[^5]: . Stokes, R. W., M. J. Rys, E. R. Russel, and J. Kerbs. *Motorist
    Understanding of Traffic Control Devices in Kansas*. Report No.
    K-Tran: KSU 94-7. Kansas State University and Kansas Department of
    Transportation. Topeka, KS, 1995.

[^6]: Agresti, A. and B. Finally. Statistical Methods for the Social
    Sciences. Second Edition. Dellen Publishing, San Francisco. 1986.

[^7]: . Federal Highway Administration. *Get the Picture. Listen to the
    Signs*. FHWA-SA-98-089. U.S. Department of Transportation,
    Washington, DC. , 1998.

[^8]: . Virginia Department of Transportation. Virginia Work Area
    Protection Manual. Richmond, Virginia, 1996.

    **LIST OF TABLES**

    Table 1. Results of the 1987 FHWA Study and this Study

    **LIST OF FIGURES**

    Figure 1. Original and Proposed Advanced Flagger Warning Signs

    Figure 2. Sample Survey Questionnaire

    Figure 3. Distribution of Responses to "Have You Seen This Sign in
    Virginia for the Existing and Proposed Signs?"

    Figure 4. Distribution of Answers to "What Do You Think This Sign
    Means For the Existing and Proposed Signs?"

    Figure 5. Distribution of Answers to "Where Would You Expect to See
    This Sign for the Existing and Proposed Signs?"

    Figure 6. Percent Distribution of Answers to "What Would You Do If
    You Saw This Sign While Driving?

    Figure 7. Flagging Operation on Two-Lane Road in Virginia