DEVELOPMENT OF BEST PRACTICES FOR PORTABLE CHANGEABLE MESSAGE

SIGN USE IN WORK ZONES FOR DESIGN AND CONSTRUCTION ENGINEERS

Submitted: November 5, 2015

Susan Paulus, P.E.

Lakeside Engineers

909 W. Mayfair Road

Wauwatosa, WI 5321

Phone: 262-789-8200 ex. 105

Fax: 262-789-8207

Email: susan.paulus@lakesideengineers.com

Number of Words: 4338

Number of References: 500

Number of Figures: 4 1000

Number of Tables: 6 1500

Total: 7338

1 Susan Paulus

ABSTRACT 1 Portable Changeable Message Sign (PCMS) use has been increasing in Wisconsin over the past 2

six years. In 2013, the Wisconsin Department of Transportation (WisDOT) spent over $2 3

million on PCMS’s during highway improvement projects. With such a large amount of money 4

being spent on PCMS’s, adequate guidance is needed to ensure PCMS’s are used properly. 5

Currently, WisDOT has limited guidance for PCMS design and field implementation. 6

WisDOT’s main design guidelines, the Facilities Development Manual [1] does not even 7

mention PCMS’s. Other WisDOT guidance documents do address some elements of PCMS use 8

[2] [3], but limited information is provided on message content and PCMS location. 9

National guidance, state-specific guidance, and existing research were reviewed to 10

determine best practices for PCMS use in work zones. This paper summarizes typical PCMS 11

use, PCMS field placement, message development, and typical applications. Finally, 12

recommendations for PCMS use in work zones are provided. Recommendations are tailored to 13

current practices in Wisconsin, but can be applied nationwide. Recommendations cover 14

advanced notice of closures and advanced warning. Advanced notice of closure guidelines are 15

developed for system ramps, service ramp, roadway closures, and lane closures. Advanced 16

warning guidelines are developed for a variety of work zone applications, including: rolling 17

closures, zipper merges, and speed reduction areas. For each scenario, typical display duration, 18

phase length, PCMS placement, and sample messages are provided. 19

20

2 Susan Paulus

INTRODUCTION 1 In the United States, about 2 percent of roadway crashes occur in work zones, amounting to 2

88,000 crashes per year [4]. However, work zone crash reporting varies by state. In Wisconsin, 3

an average 1,600 work zone crashes occur per year. This number remains relatively steady while 4

the number of injury or fatal crashes varies more. These numbers are likely under-reported as 5

the policy for reporting a “work zone crash” may differ for each local law enforcement agency 6

within Wisconsin. Preventing work zone crashes is a high priority as both road users and 7

construction workers are at a higher risk due to reduced roadway space and proximity of workers 8

to the traffic lanes, as well as other factors. 9

Portable Changeable Message Signs (PCMS’s) are one tool to provide roadway users 10

work zone information, which can reduce confusion, reduce vehicle speeds, and increase safety. 11

PCMS’s have been featured in Wisconsin Department of Transportation (WisDOT) construction 12

projects since the 1990’s, and WisDOT has continually procured contractor-owned PCMS’s by 13

special provisions or standardized special bid item. In November 2011, PCMS’s were added to 14

the State of Wisconsin Standard Specifications for Highway and Structure Construction 15

(Standard Specs) [4]. WisDOT’s PCMS use on awarded construction projects was reviewed to 16

determine the need for a revision to Wisconsin’s PCMS guidelines [5]. 17

For WisDOT projects let in 2009, 120 PCMS’s were used daily on WisDOT construction 18

projects during the typical construction season (April 1st to November 15

th). With an average bid 19

price of $68.42 per day, WisDOT spent $1.35M on PCMS’s for projects let in 2009. For 20

WisDOT projects let in 2013, PCMS use increased 152 percent from 2009, with the average bid 21

price increasing to $78.75 per day, resulting in $2.79M spent on PCMS’s for projects let in 2013. 22

See Table 1 for the annual breakdown. Note that some projects let in previous years may be 23

multi-year projects, so the actual PCMS use and total dollars spent is likely to increase. With the 24

number of PCMS’s used in work zones increasing and the price per day increasing, guidelines 25

for proper PCMS use for design and construction engineers should be developed to ensure 26

WisDOT funds are used wisely. 27

28

TABLE 1 WisDOT PCMS Use by Let Year 29

Year

Let

Estimated PCMS

(Days)

Actual PCMS

(Days)*

Average Bid

Price

Total Dollars

Spent*

2009 40,246 27,617 $ 68.42 $1,350,959

2010 44,537 39,222 $ 75.54 $1,881,562

2011 51,636 36,024 $ 69.60 $1,841,156

2012 56,530 42,193 $ 72.73 $2,024,206

2013 47,378 42,093 $ 78.75 $2,786,166

2014 48,482 33,897 $ 91.63 $1,943,251

*As of September 2015

WISCONSIN STANDARDS AND GUIDELINES 30 WisDOT developed the Facilities Development Manual (FDM) to aid in the design of highway 31

facilities [1]. Section 11-50 is devoted to traffic control; however, nowhere in the FDM are 32

PMCS’s addressed or referenced. WisDOT has also developed a Traffic Guidelines Manual 33

(TGM), containing more detailed design information on specific traffic control situations [2]. 34

Chapter 6 of the TGM includes guidance on work zone traffic control, with Section 6-2-55 titled 35

3 Susan Paulus

Portable Changeable Message Sign Use in Construction & Maintenance Projects. This 1

guideline was originally developed in September 2008 and was last updated in May 2009. 2

The TGM discusses PCMS’s in general terms, providing one typical application (i.e. 3

advanced warning of project start), and various example messages. The TGM states that all 4

PCMS’s used on highway improvement projects will be supplied and maintained by the 5

contractor and that all messages displayed must be pre-approved by the project engineer. There 6

is limited guidance for project engineers on acceptable message content in the TGM. The State 7

of Wisconsin Standard Specifications for Highway and Structure Construction, 2015 Edition 8

describes the specifications for PCMS’s, including: legend size, legibility, placement, and 9

performance [3]. 10

In Wisconsin, no statewide PCMS guidance describing PCMS use or scenario-specific 11

messages exists. In a diverse state with five different WisDOT regions, the consistency of 12

messages drivers see displayed on PCMS’s throughout the state can vary greatly. Statewide 13

guidance is needed to ensure all highway improvement projects throughout Wisconsin follow 14

consistent guidelines on PCMS use. The development of typical PCMS applications and 15

messages will help provide clear and consistent messages to the traveling public. 16

NATIONAL STANDARDS AND GUIDELINES 17 Nationwide, the Manual on Uniform Traffic Control Devices (MUTCD) contains standards and 18

guidance for PCMS use [6]. Guidance is provided in Section 6F and Section 2L and includes 19

items such as applications, legibility, visibility, appropriate abbreviations, and message content. 20

The MUTCD does not provide guidance on when to use certain messages, on the duration 21

messages should appear (i.e. the number of days), or on how messages should be worded. 22

In addition to the MUTCD, the FHWA developed the Portable Changeable Message 23

Handbook (PCMS Handbook) in 2003 [7]. This handbook discusses different types of PCMS’s, 24

standard abbreviations, legibility, and field placement. Most recently, the American Traffic 25

Safety Services Association (ATSSA) published the Guidance for the Use of Portable 26

Changeable Message Signs in Work Zones (PCMS Guidelines) in 2013 [8]. This document 27

discusses different types of PCMS’s, including advantages and disadvantages, message content, 28

field placement, and some typical applications. 29

Although these national guidelines provide a good baseline for basic PCMS principles, 30

no current document has compiled the vast amount of research on driver comprehension of 31

messages on PCMS’s. For this paper, state guidelines and standards were reviewed for a number 32

of states [9] [10] [11] [12] [13] [14], in addition to research evaluating PCMS message content 33

[15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] [26]. A compilation of the review is 34

provided below based on different aspects of PCMS’s. The last section in this paper contains 35

work zone PCMS recommendations and provides guidelines for both design and construction 36

engineers to ensure consistent PCMS use. 37

TYPICAL PCMS USE 38 The MUTCD [6] defines general uses for PCMS’s in Section 2L. Some potential uses include: 39

incident management and route diversion, special event applications associated with traffic 40

control or conditions, travel times, warning situations, and speed control. PCMS’s can also be 41

used to display safety messages or transportation-related messages, but cannot be used to display 42

advertising messages [6]. NCHRP Report 600, Human Factor Guidelines for Road Users 43

contains a chapter on Changeable Message Signs (CMS’s) [27]. The chapter begins by 44

describing appropriate CMS use, which emulates the guidance contained in the MUTCD. 45

4 Susan Paulus

Section 6F.60 of the MUTCD includes typical work zone PCMS applications: 1

Speed differentials 2

Queuing and delays 3

Adverse environmental conditions 4

Changes in alignment or surface conditions 5

Advanced notice of closures 6

Crash and incident management 7

Changes in the road pattern 8

Other agencies [9] [10] have developed hierarchies of types of messages to display on 9

work zone PCMS’s. Florida DOT (FDOT) requires PCMS use for all night work occurring 10

within 4 feet of the traveled way [14]. Indiana DOT (INDOT) developed a priority list for the 11

type of message to display; the priority (from highest to lowest) is [9]: 12

1. Road closure 13

2. Ramp closure or access restriction 14

3. Hazardous conditions 15

4. Real-time traffic information 16

5. Advanced notice for scheduled events 17

6. Public information pertinent to highway safety 18

PCMS FIELD PLACEMENT 19 The MUTCD [6] provides the following guidance on the placement of PCMS’s: 20

Locate sufficiently upstream of known bottlenecks and high crash locations to enable 21

road users to select an alternate route or take other appropriate action in response to a recurring 22

condition. 23

Locate sufficiently upstream of major diversion decision points, such as interchanges, 24

to provide adequate distance over which road users can change lanes to reach one destination or 25

the other. 26

Do not locate within an interchange except for toll plazas or managed lanes. 27

Do not position at locations where the information load on drivers is already high 28

because of guide signs and other types of information. 29

Do not locate in areas where drivers frequently perform lane-changing maneuvers in 30

response to static guide sign information, or because of merging or weaving conditions. 31

Horizontal Offset 32 PCMS’s are not crashworthy devices and should be protected. If possible, PCMS’s should be 33

placed behind barrier or guard rail, placed outside the clear zone, or protected by traffic control 34

devices [9] [11]. The horizontal offset needs to be considered, as well. The PCMS needs to be 35

in the driver’s cone of vision to ensure there is enough distance to read the message. The cone of 36

vision extends 10 degrees to the left and the right of the viewer [8]. 37

As the distance from a PCMS increases, the offset also increases. For example, on a 6-38

lane divided facility, a driver in the left lane can comfortably view a sign on the right shoulder 39

until about 200 feet from the sign. This makes the last 200 feet of visibility less useful to the 40

driver, therefore reducing the amount of time they have to view the entire message. This is not 41

typically considered in the placement of PCMS’s. FHWA’s PCMS Handbook suggests putting 42

the PCMS closest to the lane in which the message applies [7]. One study recommended placing 43

PCMS’s on both sides of the facility to ensure all drivers would receive the message [19]. 44

5 Susan Paulus

Advanced Placement to Field Conditions 1 Advanced placement to the hazard or condition should also be considered to ensure drivers have 2

adequate time to respond to the message provided. FHWA’s PCMS Handbook recommends [7]: 3

Minimum 500 feet to the decision point for a minor action, regardless of speed 4

1000 feet for a major action for speeds 40 mph or less 5

1 mile for a major action upstream for speeds 45 mph or more 6

FDOT recommends placing PCMS’s 500 to 800 feet in advance, if the PCMS is 7

supplemental to conventional traffic control devices or 0.5 to 2 miles in advance of complex 8

traffic schemes with new or unusual traffic patterns [14]. INDOT developed guidelines for 9

PCMS placement on freeways and non-freeways, as shown in Tables 2 and 3 [9]. Other agencies 10

rely on designers to determine the location and messages to be included on PCMS’s [14]. 11

In addition, placement to existing signs should also be considered. Oregon Department 12

of Transportation (ODOT) recommends [11]: 13

At least 1000 feet from guide, warning or other critical signs on freeways 14

At least 500 feet from guide, warning or other critical signs on non-freeways with 15

posted speed of 45 mph or higher – Increase distance on multi-lane roadways 16

At least 350 feet from guide, warning or other critical signs on multi-lane roads or 17

arterials with posted speed of 40 mph or less 18

At least 100 feet from guide, warning, or other critical signs on urban roads with 19

posted speed of 25 mph or less. 20

PCMS Visibility and Legibility 21 The MUTCD recommends PCMS’s should be visible for 0.5 miles on facilities with speeds 55 22

mph or greater [6]. The message should be legible for 600 feet for nighttime conditions and 800 23

feet for daytime conditions [6]. At 65 mph, this results in viewing times of 6.3 seconds and 8.4 24

seconds, respectively. WisDOT Standard Specs state that PCMS signs should be legible for 850 25

feet or 8.9 seconds under both daytime and night time operations [3]. 26

A number of documents recommend rotating the PCMS to improve visibility [7] [8] [11]. 27

Recommendations vary from 3 degrees to 10 degrees towards traffic. 28

29

6 Susan Paulus

TABLE 2 INDOT PCMS Placement on Freeways [9] 1

Event Duration

Min. #

required

per

approach

Location of

1st PCMS

Location of

2nd

PCMS

Road Closure Any length 2

1 mile in advance of

the detour exit (if

provided) or the

closure

1000’ in advance of

the detour exit (if

provided) or the

closure

Ramp Closure

Less than 1 week

Less than 1 month

for unplanned

closure

2

1 mile in advance of

detour exit (if detour is

provided) or the

closed ramp

1000’ in advance of

the detour exit (if

detour is provided)

or the closed ramp

Lane Closure w/

Anticipated Queuing Any length 2

1 mile in advance of

the previous exit

upstream of the

anticipated queue

length

1000’ in advance of

anticipated queue

length

Lane Closure

Mobile or

stationary at any

one location less

than 2 weeks

2

2500’ in advance of

previous exit upstream

of the closure

1000’ in advance of

the first

construction sign

Frequent or

Intermittent changes

in Alignment

Any length 1

1000’ in advance of

the first construction

sign

n/a

Frequent or

Intermittent Changes

in Pavement

Condition

Any length 1

1000’ in advance of

the first construction

sign

n/a

Speed Limits reduced

by 15 mph or more

for Work Zone

Any length 1

1000’ in advance of

the first construction

sign

n/a

Location with a

Significant Crash

History

Any length 1

1000’ in advance of

the first construction

sign

n/a

2

7 Susan Paulus

TABLE 3 INDOT PCMS Placement for Non-Freeways [9] 1

Event Duration

Min. #

required per

approach

Location of

1st PCMS

Road Closure Less than 2 weeks 1 500’ in advance of the

first construction sign

Side Road Closure

Less than 1 week

Less than 1 month for

unplanned closure

1 500’ in advance of the

closed side road

Lane Closure w/Peak Hour

Delay > 5 minutes Any length 1

1500’ in advance of the

first construction sign

Lane Closure

Mobile or stationary at

any one location less

than 2 weeks

1 500’ in advance of the

closed side road

Frequent or Intermittent Changes

in Alignment Any length 1

500’ in advance of the

first construction sign

Frequent or Intermittent changes

in Pavement Condition Any length 1

500’ in advance of the

first construction sign

Speed Limits reduced by 15 mph

or more for Work Zone Any length 1

500’ in advance of the

first construction sign

Location with a Significant

Crash History Any length 1

500’ in advance of the

first construction sign

MESSAGE DEVELOPMENT 2 Messages on PCMS’s need to be easily understandable as drivers have limited time to view, 3

read, comprehend, and respond to the information provided. Message development includes the 4

message’s verbiage as well as the time the message is displayed, which is also known as phase 5

length. 6

Phase Length 7 The MUTCD determines the minimum length of each phase by the lesser of one second per word 8

or two seconds per bit of information [6]. In direct contradiction to this, Duduk recommended 9

using the greater of these two values to ensure drivers have time to read the entire message [7]. 10

FHWA’s PCMS Handbook recommends phases with one or two lines to be displayed for 1.5 11

seconds and phases with three lines to be displayed for three seconds [7]. Phase length typically 12

is determined by the content of the message, and not by the available viewing time. FDOT 13

applies a different approach that requires signs to be legible at 900 feet and requires the driver be 14

able to read the entire message twice when traveling 55 mph [14]; this results in a viewing time 15

of 11.16 seconds and maximum phase duration of 2.79 seconds. Similarly, the TGM states it is 16

desirable for the driver to be able to read the entire message twice [2]. To allow drivers to read a 17

PCMS twice while approaching the sign, Table 4 was developed to determine the distance 18

traveled and required legend height based on a legibility index of 40 feet for two PCMS viewings 19

[6]. 20

21

8 Susan Paulus

TABLE 4 Required Legend Height by Speed and Display Time 1

Speed

Number

of

Phases

Phase Time

(Max)

Distance Traveled

(One Viewing)

Distance Traveled

(Two Viewings)

Legend Height

Required*

mph fps

seconds feet feet inches

70 102.67 2 4 821 1642 41.07

65 95.33 2 4 763 1526 38.13

55 80.67 2 4 645 1290 32.27

45 66.00 2 4 528 1056 26.40

35 51.33 2 4 411 822 20.53

25 36.67 2 4 293 586 14.67

*Assumes a legibility of 40 ft / in 2 3

One element of PCMS message design, which is typically disregarded, is the legend 4

height, as an 18-inch legend height has become standard on PCMS’s. Manufacturers have been 5

constructing PCMS’s with line matrix and character matrix designs that restrict the legend height 6

to the 18-inch minimum as required by the MUTCD [6]. An 18-inch legend height and a 7

legibility index of 40 ft/in impacts the viewing time drivers have to read a PCMS. As shown in 8

Table 4, an 18-inch legend is only adequate for speeds below 35 mph, if the message is displayed 9

for 8 seconds. 10

The shortcomings of the 18-inch legend height were described in FHWA’s PCMS 11

Handbook, where 18-inch legend was associated with a legibility distance of 720 feet, suitable 12

for 40 mph [7]. These shortcomings have not been addressed in the various state and nationwide 13

guidance that are currently available. A 2008 study confirmed the 40 ft/in legibility index by 14

evaluating a number of PCMS signs based on legibility of a word message and an “eye chart” 15

message; the results are shown in Table 5 [28]. This evaluation included three evaluators with 16

corrected 20/20 vision driving towards the sign; however, their travel speeds were not recorded. 17

18

TABLE 5 Measured PCMS Legibility 19

PCMS Number Legibility Distance (feet)

Day, Word Day, Eye Chart Night, Word Night, Eye Chart

PCMS(2008)- 03 962 896 814 639

PCMS(2008)- 04 1031 751 918 804

PCMS(2008)- 05 702 559 611 519

PCMS(2008)- 06 712 621 582 455

PCMS(2008)- 07 1116 843 859 720

PCMS(2008)- 08 750 629 641 471

PCMS(2008)- 10 853 702 891 601

Average 875 714 759 601

Legibility (X ft /18 in) 48.6 39.7 42.2 33.4

20

Recommended guidance on the length of message and the phase time is shown in Table 21

6. This recommendation will ensure drivers have adequate time to view and read the message 22

provided for the varying speed limits. For speeds 55 mph or more, the two phases should be 23

limited in length to ensure the message can be read. Using messages with varied phase lengths 24

9 Susan Paulus

(i.e. three seconds and two seconds, etc.) can help ensure drivers have the maximum amount of 1

time to read the entire message. 2

3

TABLE 6 PCMS Phase Recommendations for 18-inch Legend 4

Speed Legend Height Maximum

Viewing Time*

Max Number

of Phases

Phase Time

(Max)

Number of

Phases Viewed

mph fps inches seconds

seconds

70 102.67 18 7.01 2 3 2.3

65 95.33 18 7.55 2 3 2.5

55 80.67 18 8.93 2 3 3.0

45 66.00 18 10.91 2 3 3.6

35 51.33 18 14.03 2 4 3.5

25 36.67 18 19.64 2 4 4.9

*Assumes a legibility of 40 ft / in 5

Message Verbiage 6 Messages need to be concise and readable in the allotted phase time. All messages displayed on 7

PCMS’s must be relevant [27]. Misleading or unreliable messages reduce the credibility of 8

PCMS’s. A proper message should be short and easily understandable. A number of sources 9

discuss the content of a PCMS message, including the MUTCD [27], the FHWA PCMS 10

Handbook [7], and various state guidelines. 11

Units of Information 12

The MUTCD states the length of the message should not have more than four units of 13

information [6]. The unit of information may include: what, where, who, and desired response. 14

Depending on the individual situation, the bits of information could be provided on one or two 15

phases. All messages may not require all bits of information. ATSSA’s PCMS Guidelines 16

recommend keeping the message as short as possible to aid in driver readability and 17

comprehension [8]. The FHWA PCMS Handbook provides recommendations on the phase 18

content based on the number of phases used [7]: 19

One-Phase PCMS: 20

o Line 1—Describe problem 21

o Line 2—Identify location or distance ahead 22

o Line 3—Provide motorist instruction 23

Two-Phase PCMS: 24

o Phase 1—Describe problem 25

o Phase 2—Provide motorist instruction 26

The TGM recommends the first phase should describe the condition that may be 27

encountered, and the second phase should advise the driver of the appropriate response [2]. 28

Message Content 29

In Wisconsin, the limited guidance on message content is provided in the TGM [2]. The TGM 30

refers to the MUTCD abbreviation list, and provides a list of messages that could be considered 31

for use. ODOT has developed a number of typical messages, and Texas Department of 32

Transportation developed a two page field guide with standard messages for field staff [25]. 33

10 Susan Paulus

Additional message content guidance was developed in NCHRP 600 [27] [26], including: 1

Abbreviations should be avoided where possible. 2

Use days of the week rather than calendar dates if the dates are in the next week. 3

If dates are used, use the three-letter month abbreviation and only display the month 4

once. 5

Do not display the day, date, and time information at once. 6

Other studies have been completed, and guidelines have been developed covering 7

different aspects of PCMS messages. ODOT developed a policy for locations and distances [11]. 8

For distances under 0.25 mile, “feet” should be used. For miles, fractions are acceptable, but 9

mile posts should not be used as they are not easily understood. ODOT also recommends using 10

the 12 hour time format followed by AM or PM [11]. 11

An additional study looked at flashing messages that included a two-phase message with 12

three lines of text and one line changing between phases [24]. The study found drivers could 13

recall the message; however, average reading times increased significantly. One common 14

example is “TRUCKS EXITING RIGHT / TRUCKS ENTERING RIGHT”. 15

Other studies have evaluated messages for emergency purposes [21]. Flooding 16

emergencies that are likely to occur in a work zone due to construction activities were evaluated. 17

The word “FLOODED” was evaluated; however, there was no consensus as to whether study 18

participants would continue on the roadway or not [21]. Additional information needs to be 19

provided, such as the specific location of the flooding or the exit to divert from the facility [21]. 20

Sequential PCMS’s 21

For freeways, a maximum of seven words is recommended, and for facilities with speeds less 22

than 55 mph, a maximum of eight words is recommended [27]. If more information needs to be 23

provided, the use of a sequential PCMS is recommended. The second PCMS should be placed 24

1000 feet from the first. One study looked at the comprehension of sequential PCMS’s and 25

found: 26

Including five units of information between the two PCMS’s results in low 27

comprehension rates 28

Using four units of information results in the same comprehension as the same 29

information on a Dynamic Message Sign 30

Repeating one unit of information on both PCMS’s can enhance comprehension [23]. 31

Message Layout 32

The MUTCD provides the standard that a PCMS shall consist of no more than two phases, 33

containing no more than three lines of text per phase. The message shall be understandable 34

regardless of the order being read. The messages shall be centered within each line of the legend 35

[6]. 36

Graphics 37

A number of studies have looked at the addition of graphics to CMSs [17] [22] [15] [18]. 38

Overall, well designed graphics can aid in comprehension of a message, especially for non-39

native language speakers and elderly drivers. Drivers prefer text over graphics that replace text; 40

however, drivers respond quickly to graphic displays that replace text [15]. Graphics can also 41

more easily describe complex situations that are hard to explain with text. 42

11 Susan Paulus

TYPICAL APPLICATIONS 1 Some state guidance and national research include typical PCMS applications. Those that are 2

currently documented are summarized in this section. 3

Speed Management 4 Speed management refers to situations where a reduced speed is desired due to hazards, work 5

zones, adverse weather, incidents, or congestion [27] [20]. Applications are temporary in nature, 6

so PCMS’s are ideal for these situations. In work zones, speed management may be considered 7

when there is a high incidence of speeding drivers, high speed variance, high number of rear end 8

crashes, or change in conditions within the work zone [8]. General guidelines include [8] [27]: 9

Provide a reason for the reduced speed 10

Limit safety messages 11

Use PCMS for speed reduction and enforcement 12

Use in work zones greater than 3,500 feet in length 13

Place PCMS 500 to 1000 feet from the hazard within the work zone 14

Do not place PCMS in high demand areas (tapers, interchanges, etc.) 15

Show speeds of vehicles passing by 16

Monitor and display real time conditions downstream 17

Show current information about speed limits, delays, or construction 18

Another study found the addition of graphics aided in reducing vehicle speeds by up to 19

17 percent [18]. 20

Inattentive Driving 21 Inattentive driving is a problem in work zones and can have severe consequences [8]. PCMS’s 22

demand higher attention than regular static signage; therefore, they bring attention to the unique 23

situation ahead. PCMS’s should be considered to reduce inattentive driving in work zones with 24

the following characteristics: greater than one mile in length, locations of unexpected queues, 25

challenging or unique situations, or easy to miss maneuvers [8]. 26

Demand Management 27 PCMS’s may be used in work zones for demand management; these situations typically include 28

heavily traveled work zones (where peak demand exceeds capacity) or where queueing is 29

expected that will impact traffic and/or the construction schedule [8]. California implemented 30

this method by using existing roadway sensors to monitor traffic traveling through an I-15 work 31

zone [19]. By providing users with information via CMS’s in advance of decision points, the 32

maximum delay was reduced from 90 minutes to 45 minutes during construction. The messages 33

provided on the CMS’s considered both the construction roadway as well as alternate routes. 34

Detour information was only provided when available detour routes had additional capacity. 35

Advanced Notice 36 Advanced notice on PCMS’s involves making the public aware of a road, lane, or ramp closing 37

in advance of the closure. ODOT recommends limiting the display of this information to drivers 38

to two weeks before the closure takes place [11]. Minnesota Department of Transportation 39

developed more specific guidelines based on the type of closure, time of closing (weekday vs. 40

weekend), duration of closure (long-term vs. short-term) [10]. 41

12 Susan Paulus

WORK ZONE PCMS RECOMMENDATIONS 1 This section presents recommendations for PCMS use in work zones. The recommendations are 2

tailored to current practices in Wisconsin but consider all the national guidance available. These 3

recommendations can be used by design and construction engineers throughout the U.S. to 4

ensure consistent messages. 5

Advanced Notice of Closures 6 Advanced notice of closures refers to the full or partial closure of a facility. Recommendations 7

are shown in Figures 1 and 2. 8

System Ramp Closures 9

For system ramp closures, place the PMCS along the ramp in which the message applies. During 10

the actual closure, a PCMS should be placed to alert drivers of the closure and provide 11

alternative route information. If the detour is before the driver reaches the closed ramp, provide 12

a PCMS 0.5 miles before the detour or alternative route exit. If the detour is after the closed 13

ramp, place a PMCS near the closed ramp. 14

Service Ramp Closures 15

For service ramp closures, place the PMCS along the ramp in which the message applies. If 16

detours are provided, follow the System Ramp Closure guidelines above. For PCMS’s on non-17

freeways, the sign should be placed 500 to 1,000 feet advance of the preferred detour route. 18

Roadway Closures 19

For roadway closures, place the PCMS at the point of closure. During the actual closure, a 20

PCMS should be placed to alert drivers of the closure and provide alternative route information. 21

Provide a PCMS 0.5 miles before the detour route. An additional PCMS may be placed further 22

upstream if capacity is expected to be exceeded on the detour route and other alternative routes 23

are available. 24

Lane Closures 25

Under usual circumstances, PCMS’s will not be used to give advanced notice of lane closures. 26

Exceptions may include sporting events, holiday weekends, and other high traffic events in 27

which some traffic may divert to alternative routes if they are aware of closures. 28

29

13 Susan Paulus

1

2

System Ramp

Closure Type

Advanced

Notice Example Message

Phase Length

(sec)

Continuous Closure 7

days or greater 14 days

RAMP TO

CLOSE

APR 25 TO

MAY 25 2 / 2

RAMP

TO CLOSE LONGTERM

FRIDAY OCT 1 9PM

3 / 2

Continuous Closure 7

days or less 7 days

RAMP TO

CLOSE APR 25-29 2 / 2

Nightly or Daily

Closures 7 days

RAMP TO

CLOSE

NIGHTLY 9PM-5AM

2 / 3

Weekend Closures 10 days (begin

Thursday before)

RAMP TO

CLOSE

FRI 9PM TO

MON 6AM 2 / 3

Service Ramp

Closure Type

Advanced

Notice Example Message

Phase Length

(sec)

Continuous Closure 7

days or greater 10 days

RAMP TO

CLOSE

APR 25 TO

MAY 25 2 / 3

Continuous Closure 7

days or less 3 to 7 days

RAMP TO

CLOSE

APR 25-29 2 / 2

Nightly or Daily

Closures 3 to 7 days

RAMP TO

CLOSE

NIGHTLY 9PM-5AM

2 / 3

Detour Type Example Message Phase Length

(sec)

None Posted or Preferred RAMP

CLOSED

USE ALT

ROUTE 2 / 2

Signed Detour (upstream of closure) RAMP

TO 10 EB CLOSED

USE CTH BB

3 / 2

US 10 EB

RAMP CLOSED

USE BB TO 47

3 / 2

I 43 NB RAMP

CLOSED

USE NEXT EXIT

3 / 2

Signed Detour (downstream of closure) RAMP

CLOSED

USE WIS 47

2 / 2

FIGURE 1 Recommended PCMS Messages for Ramp Closures. 3 4

5

6

14 Susan Paulus

1

Roadway Closure Type Advanced

Notice Example Message

Phase Length

(sec)

Continuous Closure 7 days

or greater 10 days

ROAD TO

CLOSE

APR 25 TO

MAY 25 2 / 3

Continuous Closure 7 days

or less 3 to 7 days

ROAD TO

CLOSE

APR 25-29

2 / 2

Nightly or Daily Closures 3 to 7 days ROAD

TO CLOSE

NIGHTLY 9PM-5AM

2 / 3

ROAD

TO CLOSE

MON-THUR 8PM-5AM

2 / 3

Detour Sign Location Example Message Phase Length

(sec)

At Closure ROAD

CLOSED

EXIT RIGHT ---->

2 / 2

Advance of Closure ROAD

CLOSED 1 MILE

FOLLOW DETOUR

3 / 2

FREEWAY CLOSED AHEAD

EXPECT DELAYS

3 / 2

ROAD

CLOSED AT US 41

USE ALT

ROUTE 3 / 3

FIGURE 2 Recommended PCMS Messages for Roadway Closures. 2

Advanced Warning 3 Advanced warning applies to a number of different situations. PCMS’s can be used to enhance 4

an existing static sign after a configuration change, provide a time-specific warning, or provide a 5

warning about an on-going event. Recommendations are shown in Figures 3 and 4. 6

Another advance warning situation is for rolling slowdowns. Typically, minimal 7

advanced notice is given to the public before a rolling slowdown. A PCMS should be placed 8

before the start of the rolling slowdown at a distance that encompasses the expected queue 9

length. Other PCMS’s should be placed along the route to ensure traffic is aware of the 10

slowdown. 11

The zipper merge or dynamic late merge is a strategy directing drivers to stay in their 12

lane until the merge point, which has been shown to increase capacity at the merge. PCMS’s are 13

used in real time to show messages when queueing is detected. When there is no queueing, the 14

PMCS’s should remain blank. 15

16

15 Susan Paulus

Advanced

Warning Type

Location of

PCMS

Time Period

to Display Example Message

Phase Length

(sec)

Traffic Pattern

Change

500’ to 1000’

in advance 7 days

NEW TRAFFIC

PATTERN

Traffic Shift 500’ to 1000’

in advance 7 days

TRAFFIC SHIFTS RIGHT

New Signal Beyond

expected queue 7 days

SIGNAL AHEAD X MILES

BE PREPARED TO STOP

3 / 2

Work in Lane

Closure

500’ to 1000’

in advance

During Night

Work

WORKERS IN ROAD AHEAD

SLOWDOWN IN

WORKZONE 3 / 2

Paving in Adjacent

Lane

500’ to 1000’

in advance During Work

PAVING NEXT

X MILES

WORKERS ON

RIGHT 3 / 2

Flagging Beyond

expected queue During Work

FLAGGER AHEAD

PREPARE TO

STOP 2 / 3

Truck

Egress/Access

500’ to 1000’

in advance During Work

TRUCKS ENTERING

RIGHT

ON RIGHT TRUCKS EXITING

3 / 3

Rough Road

Advance of

alternative

route

During Event ROUGH ROAD 1 MILE

Flooding

Advance of

alternative

route

During Event ROAD

FLOODED AT US 10

USE NEXT EXIT

3 / 2

Rolling Slowdown Advance of

Slowdown During Event

SLOWED TRAFFIC AHEAD

XX MPH NEXT

XX MILES 3 / 2

Rolling Slowdown Advance of

Slowdown During Event

SLOWED TRAFFIC

DO NOT PASS

2 / 2

Zipper Merge At merge point During Event MERGE HERE

TAKE TURNS

2 / 2

Zipper Merge Ahead of

merge During Event

USE ALL

LANES

DO NOT

MERGE 2 / 2

Zipper Merge

Advanced

warning on

other facilities

During Event I-94

WESTBND

BACKUPS AHEAD

2 / 2

FIGURE 3 Recommended PCMS Messages for Advanced Warning (1 of 2). 1 2

16 Susan Paulus

Speed management refers to situations where a reduced speed is desired and tools are 1

used to measure vehicle speeds as they pass through the work zone. Typical applications include 2

as drivers enter a work zone or within a reduced regulatory speed segment. 3

PCMS’s can be used to display real time information about travel times, delays, queues, 4

or other traffic impacts. These messages can be generated from a contractor-supplied system or 5

from incorporation into the existing detection. Additionally, messages could be used at specific 6

times of the day when queues are expected that would not be anticipated by road users. 7

8

Advanced

Warning Type

Location of

PCMS

Time Period

to Display Example Message

Phase Length

(sec)

Speed Management

500’ to 1000’

in advance of

hazard

During Work YOU ARE SPEEDING

SLOW DOWN

2 / 2

Speed Management

500’ to 1000’

in advance of

hazard

During Work

YOUR SPEED IS XX MPH

SLOW DOWN 3 / 2

Speed Management

500’ to 1000’

in advance of

hazard

During Work

YOUR SPEED IS XX MPH

THANKS FOR NOT SPEEDING

3 / 3

Speed Management

500’ to 1000’

in advance of

hazard

During Work

YOU ARE SPEEDING

MINIMUM FINE $XXX

2 / 2

Real Time Travel

Time Main Route

Advance of an

alternative

route

While delays

are present or

continuously

15 MINS TO I-94

Real Time Travel

Time Alt Route

Advance of an

alternative

route

While delays

are present or

continuously

15 MINS TO I-94 VIA 10

USE ALT

ROUTE 3 / 2

Real Time Travel

Time Comparison

Advance of an

alternative

route

While delays

are present or

continuously

25 MINS TO I-94

15 MINS TO I-94 VIA 10

3 / 3

Real Time Queuing

1 to 2 miles in

advance of end

of queue

During

queueing

STOPPED TRAFFIC X MILES

EXPECT DELAYS

3 / 2

Anticipated

Queuing

1 mile in

advance of end

of queue

During

anticipated

queueing

SLOWED TRAFFIC 1 MILE

LEFT LANE

CLOSED 3 / 2

Slowed Traffic ½ to 1 mile in

advance

During

expected or

measured

LFT LANE NARROWS

1500 FT

SLOWED TRAFFIC AHEAD

3 / 3

Event Traffic

Advance of

alternative

route

During Event EVENT

TRAFFIC 2 MILES

EXPECT DELAYS

3 / 2

FIGURE 4 Recommended PCMS Messages for Advanced Warning (2 of 2). 9 10

17 Susan Paulus

ACKNOWLEDGMENT 1 Dr. David Noyce provided valuable direction and oversight in completing this work for an 2

independent study course at the University of Wisconsin-Madison. 3

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18 Susan Paulus

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1

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