DEVELOPMENT OF BEST PRACTICES FOR PORTABLE CHANGEABLE MESSAGE SIGN USE IN WORK ZONES FOR DESIGN AND CONSTRUCTION ENGINEERS Submitted: November, 0 Susan Paulus, P.E. Lakeside Engineers 0 W. Mayfair Road Wauwatosa, WI Phone: --00 ex. 0 Fax: --0 Email: susan.paulus@lakesideengineers.com Number of Words: Number of References: 00 Number of Figures: 000 Number of Tables: 00 Total:
Susan Paulus 0 0 ABSTRACT Portable Changeable Message Sign (PCMS) use has been increasing in Wisconsin over the past six years. In 0, the Wisconsin Department of Transportation (WisDOT) spent over $ million on PCMS s during highway improvement projects. With such a large amount of money being spent on PCMS s, adequate guidance is needed to ensure PCMS s are used properly. Currently, WisDOT has limited guidance for PCMS design and field implementation. WisDOT s main design guidelines, the Facilities Development Manual [] does not even mention PCMS s. Other WisDOT guidance documents do address some elements of PCMS use [] [], but limited information is provided on message content and PCMS location. National guidance, state-specific guidance, and existing research were reviewed to determine best practices for PCMS use in work zones. This paper summarizes typical PCMS use, PCMS field placement, message development, and typical applications. Finally, recommendations for PCMS use in work zones are provided. Recommendations are tailored to current practices in Wisconsin, but can be applied nationwide. Recommendations cover advanced notice of closures and advanced warning. Advanced notice of closure guidelines are developed for system ramps, service ramp, roadway closures, and lane closures. Advanced warning guidelines are developed for a variety of work zone applications, including: rolling closures, zipper merges, and speed reduction areas. For each scenario, typical display duration, phase length, PCMS placement, and sample messages are provided.
Susan Paulus 0 0 0 INTRODUCTION In the United States, about percent of roadway crashes occur in work zones, amounting to,000 crashes per year []. However, work zone crash reporting varies by state. In Wisconsin, an average,00 work zone crashes occur per year. This number remains relatively steady while the number of injury or fatal crashes varies more. These numbers are likely under-reported as the policy for reporting a work zone crash may differ for each local law enforcement agency within Wisconsin. Preventing work zone crashes is a high priority as both road users and construction workers are at a higher risk due to reduced roadway space and proximity of workers to the traffic lanes, as well as other factors. Portable Changeable Message Signs (PCMS s) are one tool to provide roadway users work zone information, which can reduce confusion, reduce vehicle speeds, and increase safety. PCMS s have been featured in Wisconsin Department of Transportation (WisDOT) construction projects since the 0 s, and WisDOT has continually procured contractor-owned PCMS s by special provisions or standardized special bid item. In November 0, PCMS s were added to the State of Wisconsin Standard Specifications for Highway and Structure Construction (Standard Specs) []. WisDOT s PCMS use on awarded construction projects was reviewed to determine the need for a revision to Wisconsin s PCMS guidelines []. For WisDOT projects let in 00, 0 PCMS s were used daily on WisDOT construction projects during the typical construction season (April st to November th ). With an average bid price of $. per day, WisDOT spent $.M on PCMS s for projects let in 00. For WisDOT projects let in 0, PCMS use increased percent from 00, with the average bid price increasing to $. per day, resulting in $.M spent on PCMS s for projects let in 0. See Table for the annual breakdown. Note that some projects let in previous years may be multi-year projects, so the actual PCMS use and total dollars spent is likely to increase. With the number of PCMS s used in work zones increasing and the price per day increasing, guidelines for proper PCMS use for design and construction engineers should be developed to ensure WisDOT funds are used wisely. TABLE WisDOT PCMS Use by Let Year Year Let Estimated PCMS (Days) Actual PCMS (Days)* Average Bid Price Total Dollars Spent* 00 0,, $. $,0, 00,, $. $,, 0,,0 $.0 $,, 0,0, $. $,0,0 0,,0 $. $,, 0,, $. $,, *As of September 0 WISCONSIN STANDARDS AND GUIDELINES WisDOT developed the Facilities Development Manual (FDM) to aid in the design of highway facilities []. Section -0 is devoted to traffic control; however, nowhere in the FDM are PMCS s addressed or referenced. WisDOT has also developed a Traffic Guidelines Manual (TGM), containing more detailed design information on specific traffic control situations []. Chapter of the TGM includes guidance on work zone traffic control, with Section -- titled
Susan Paulus 0 0 0 0 Portable Changeable Message Sign Use in Construction & Maintenance Projects. This guideline was originally developed in September 00 and was last updated in May 00. The TGM discusses PCMS s in general terms, providing one typical application (i.e. advanced warning of project start), and various example messages. The TGM states that all PCMS s used on highway improvement projects will be supplied and maintained by the contractor and that all messages displayed must be pre-approved by the project engineer. There is limited guidance for project engineers on acceptable message content in the TGM. The State of Wisconsin Standard Specifications for Highway and Structure Construction, 0 Edition describes the specifications for PCMS s, including: legend size, legibility, placement, and performance []. In Wisconsin, no statewide PCMS guidance describing PCMS use or scenario-specific messages exists. In a diverse state with five different WisDOT regions, the consistency of messages drivers see displayed on PCMS s throughout the state can vary greatly. Statewide guidance is needed to ensure all highway improvement projects throughout Wisconsin follow consistent guidelines on PCMS use. The development of typical PCMS applications and messages will help provide clear and consistent messages to the traveling public. NATIONAL STANDARDS AND GUIDELINES Nationwide, the Manual on Uniform Traffic Control Devices (MUTCD) contains standards and guidance for PCMS use []. Guidance is provided in Section F and Section L and includes items such as applications, legibility, visibility, appropriate abbreviations, and message content. The MUTCD does not provide guidance on when to use certain messages, on the duration messages should appear (i.e. the number of days), or on how messages should be worded. In addition to the MUTCD, the FHWA developed the Portable Changeable Message Handbook (PCMS Handbook) in 00 []. This handbook discusses different types of PCMS s, standard abbreviations, legibility, and field placement. Most recently, the American Traffic Safety Services Association (ATSSA) published the Guidance for the Use of Portable Changeable Message Signs in Work Zones (PCMS Guidelines) in 0 []. This document discusses different types of PCMS s, including advantages and disadvantages, message content, field placement, and some typical applications. Although these national guidelines provide a good baseline for basic PCMS principles, no current document has compiled the vast amount of research on driver comprehension of messages on PCMS s. For this paper, state guidelines and standards were reviewed for a number of states [] [0] [] [] [] [], in addition to research evaluating PCMS message content [] [] [] [] [] [0] [] [] [] [] [] []. A compilation of the review is provided below based on different aspects of PCMS s. The last section in this paper contains work zone PCMS recommendations and provides guidelines for both design and construction engineers to ensure consistent PCMS use. TYPICAL PCMS USE The MUTCD [] defines general uses for PCMS s in Section L. Some potential uses include: incident management and route diversion, special event applications associated with traffic control or conditions, travel times, warning situations, and speed control. PCMS s can also be used to display safety messages or transportation-related messages, but cannot be used to display advertising messages []. NCHRP Report 00, Human Factor Guidelines for Road Users contains a chapter on Changeable Message Signs (CMS s) []. The chapter begins by describing appropriate CMS use, which emulates the guidance contained in the MUTCD.
Susan Paulus 0 0 0 0 Section F.0 of the MUTCD includes typical work zone PCMS applications: Speed differentials Queuing and delays Adverse environmental conditions Changes in alignment or surface conditions Advanced notice of closures Crash and incident management Changes in the road pattern Other agencies [] [0] have developed hierarchies of types of messages to display on work zone PCMS s. Florida DOT (FDOT) requires PCMS use for all night work occurring within feet of the traveled way []. Indiana DOT (INDOT) developed a priority list for the type of message to display; the priority (from highest to lowest) is []:. Road closure. Ramp closure or access restriction. Hazardous conditions. Real-time traffic information. Advanced notice for scheduled events. Public information pertinent to highway safety PCMS FIELD PLACEMENT The MUTCD [] provides the following guidance on the placement of PCMS s: Locate sufficiently upstream of known bottlenecks and high crash locations to enable road users to select an alternate route or take other appropriate action in response to a recurring condition. Locate sufficiently upstream of major diversion decision points, such as interchanges, to provide adequate distance over which road users can change lanes to reach one destination or the other. Do not locate within an interchange except for toll plazas or managed lanes. Do not position at locations where the information load on drivers is already high because of guide signs and other types of information. Do not locate in areas where drivers frequently perform lane-changing maneuvers in response to static guide sign information, or because of merging or weaving conditions. Horizontal Offset PCMS s are not crashworthy devices and should be protected. If possible, PCMS s should be placed behind barrier or guard rail, placed outside the clear zone, or protected by traffic control devices [] []. The horizontal offset needs to be considered, as well. The PCMS needs to be in the driver s cone of vision to ensure there is enough distance to read the message. The cone of vision extends 0 degrees to the left and the right of the viewer []. As the distance from a PCMS increases, the offset also increases. For example, on a - lane divided facility, a driver in the left lane can comfortably view a sign on the right shoulder until about 00 feet from the sign. This makes the last 00 feet of visibility less useful to the driver, therefore reducing the amount of time they have to view the entire message. This is not typically considered in the placement of PCMS s. FHWA s PCMS Handbook suggests putting the PCMS closest to the lane in which the message applies []. One study recommended placing PCMS s on both sides of the facility to ensure all drivers would receive the message [].
Susan Paulus 0 0 Advanced Placement to Field Conditions Advanced placement to the hazard or condition should also be considered to ensure drivers have adequate time to respond to the message provided. FHWA s PCMS Handbook recommends []: Minimum 00 feet to the decision point for a minor action, regardless of speed 000 feet for a major action for speeds 0 mph or less mile for a major action upstream for speeds mph or more FDOT recommends placing PCMS s 00 to 00 feet in advance, if the PCMS is supplemental to conventional traffic control devices or 0. to miles in advance of complex traffic schemes with new or unusual traffic patterns []. INDOT developed guidelines for PCMS placement on freeways and non-freeways, as shown in Tables and []. Other agencies rely on designers to determine the location and messages to be included on PCMS s []. In addition, placement to existing signs should also be considered. Oregon Department of Transportation (ODOT) recommends []: At least 000 feet from guide, warning or other critical signs on freeways At least 00 feet from guide, warning or other critical signs on non-freeways with posted speed of mph or higher Increase distance on multi-lane roadways At least 0 feet from guide, warning or other critical signs on multi-lane roads or arterials with posted speed of 0 mph or less At least 00 feet from guide, warning, or other critical signs on urban roads with posted speed of mph or less. PCMS Visibility and Legibility The MUTCD recommends PCMS s should be visible for 0. miles on facilities with speeds mph or greater []. The message should be legible for 00 feet for nighttime conditions and 00 feet for daytime conditions []. At mph, this results in viewing times of. seconds and. seconds, respectively. WisDOT Standard Specs state that PCMS signs should be legible for 0 feet or. seconds under both daytime and night time operations []. A number of documents recommend rotating the PCMS to improve visibility [] [] []. Recommendations vary from degrees to 0 degrees towards traffic.
Susan Paulus TABLE INDOT PCMS Placement on Freeways [] Min. # Event Duration required per approach Road Closure Any length Ramp Closure Lane Closure w/ Anticipated Queuing Lane Closure Frequent or Intermittent changes in Alignment Frequent or Intermittent Changes in Pavement Condition Speed Limits reduced by mph or more for Work Zone Location with a Significant Crash History Less than week Less than month for unplanned closure Any length Mobile or stationary at any one location less than weeks Any length Any length Any length Any length Location of st PCMS mile in advance of the detour exit (if provided) or the closure mile in advance of detour exit (if detour is provided) or the closed ramp mile in advance of the previous exit upstream of the anticipated queue length 00 in advance of previous exit upstream of the closure 000 in advance of the first construction sign 000 in advance of the first construction sign 000 in advance of the first construction sign 000 in advance of the first construction sign Location of nd PCMS 000 in advance of the detour exit (if provided) or the closure 000 in advance of the detour exit (if detour is provided) or the closed ramp 000 in advance of anticipated queue length 000 in advance of the first construction sign n/a n/a n/a n/a
Susan Paulus TABLE INDOT PCMS Placement for Non-Freeways [] Min. # Event Duration required per approach Road Closure Less than weeks Side Road Closure Lane Closure w/peak Hour Delay > minutes Lane Closure Frequent or Intermittent Changes in Alignment Frequent or Intermittent changes in Pavement Condition Speed Limits reduced by mph or more for Work Zone Location with a Significant Crash History Less than week Less than month for unplanned closure Any length Mobile or stationary at any one location less than weeks Any length Any length Any length Any length Location of st PCMS 00 in advance of the first construction sign 00 in advance of the closed side road 00 in advance of the first construction sign 00 in advance of the closed side road 00 in advance of the first construction sign 00 in advance of the first construction sign 00 in advance of the first construction sign 00 in advance of the first construction sign 0 0 MESSAGE DEVELOPMENT Messages on PCMS s need to be easily understandable as drivers have limited time to view, read, comprehend, and respond to the information provided. Message development includes the message s verbiage as well as the time the message is displayed, which is also known as phase length. Phase Length The MUTCD determines the minimum length of each phase by the lesser of one second per word or two seconds per bit of information []. In direct contradiction to this, Duduk recommended using the greater of these two values to ensure drivers have time to read the entire message []. FHWA s PCMS Handbook recommends phases with one or two lines to be displayed for. seconds and phases with three lines to be displayed for three seconds []. Phase length typically is determined by the content of the message, and not by the available viewing time. FDOT applies a different approach that requires signs to be legible at 00 feet and requires the driver be able to read the entire message twice when traveling mph []; this results in a viewing time of. seconds and maximum phase duration of. seconds. Similarly, the TGM states it is desirable for the driver to be able to read the entire message twice []. To allow drivers to read a PCMS twice while approaching the sign, Table was developed to determine the distance traveled and required legend height based on a legibility index of 0 feet for two PCMS viewings [].
Susan Paulus 0 0 TABLE Required Legend Height by Speed and Display Time Number Phase Time Distance Traveled Distance Traveled Speed of (Max) (One Viewing) (Two Viewings) Phases Legend Height Required* mph fps seconds feet feet inches 0 0..0.. 0. 0..00 0.0. 0... *Assumes a legibility of 0 ft / in One element of PCMS message design, which is typically disregarded, is the legend height, as an -inch legend height has become standard on PCMS s. Manufacturers have been constructing PCMS s with line matrix and character matrix designs that restrict the legend height to the -inch minimum as required by the MUTCD []. An -inch legend height and a legibility index of 0 ft/in impacts the viewing time drivers have to read a PCMS. As shown in Table, an -inch legend is only adequate for speeds below mph, if the message is displayed for seconds. The shortcomings of the -inch legend height were described in FHWA s PCMS Handbook, where -inch legend was associated with a legibility distance of 0 feet, suitable for 0 mph []. These shortcomings have not been addressed in the various state and nationwide guidance that are currently available. A 00 study confirmed the 0 ft/in legibility index by evaluating a number of PCMS signs based on legibility of a word message and an eye chart message; the results are shown in Table []. This evaluation included three evaluators with corrected 0/0 vision driving towards the sign; however, their travel speeds were not recorded. TABLE Measured PCMS Legibility PCMS Number Legibility Distance (feet) Day, Word Day, Eye Chart Night, Word Night, Eye Chart PCMS(00)- 0 PCMS(00)- 0 0 0 PCMS(00)- 0 0 PCMS(00)- 0 PCMS(00)- 0 0 PCMS(00)- 0 0 PCMS(00)- 0 0 0 Average 0 Legibility (X ft / in).... Recommended guidance on the length of message and the phase time is shown in Table. This recommendation will ensure drivers have adequate time to view and read the message provided for the varying speed limits. For speeds mph or more, the two phases should be limited in length to ensure the message can be read. Using messages with varied phase lengths
Susan Paulus 0 0 0 (i.e. three seconds and two seconds, etc.) can help ensure drivers have the maximum amount of time to read the entire message. TABLE PCMS Phase Recommendations for -inch Legend Speed Legend Height Maximum Viewing Time* Max Number of Phases Phase Time (Max) Number of Phases Viewed mph fps inches seconds seconds 0 0..0.... 0...0.00 0....0.... *Assumes a legibility of 0 ft / in Message Verbiage Messages need to be concise and readable in the allotted phase time. All messages displayed on PCMS s must be relevant []. Misleading or unreliable messages reduce the credibility of PCMS s. A proper message should be short and easily understandable. A number of sources discuss the content of a PCMS message, including the MUTCD [], the FHWA PCMS Handbook [], and various state guidelines. Units of Information The MUTCD states the length of the message should not have more than four units of information []. The unit of information may include: what, where, who, and desired response. Depending on the individual situation, the bits of information could be provided on one or two phases. All messages may not require all bits of information. ATSSA s PCMS Guidelines recommend keeping the message as short as possible to aid in driver readability and comprehension []. The FHWA PCMS Handbook provides recommendations on the phase content based on the number of phases used []: One-Phase PCMS: o Line Describe problem o Line Identify location or distance ahead o Line Provide motorist instruction Two-Phase PCMS: o Phase Describe problem o Phase Provide motorist instruction The TGM recommends the first phase should describe the condition that may be encountered, and the second phase should advise the driver of the appropriate response []. Message Content In Wisconsin, the limited guidance on message content is provided in the TGM []. The TGM refers to the MUTCD abbreviation list, and provides a list of messages that could be considered for use. ODOT has developed a number of typical messages, and Texas Department of Transportation developed a two page field guide with standard messages for field staff [].
0 Susan Paulus 0 0 0 0 Additional message content guidance was developed in NCHRP 00 [] [], including: Abbreviations should be avoided where possible. Use days of the week rather than calendar dates if the dates are in the next week. If dates are used, use the three-letter month abbreviation and only display the month once. Do not display the day, date, and time information at once. Other studies have been completed, and guidelines have been developed covering different aspects of PCMS messages. ODOT developed a policy for locations and distances []. For distances under 0. mile, feet should be used. For miles, fractions are acceptable, but mile posts should not be used as they are not easily understood. ODOT also recommends using the hour time format followed by AM or PM []. An additional study looked at flashing messages that included a two-phase message with three lines of text and one line changing between phases []. The study found drivers could recall the message; however, average reading times increased significantly. One common example is TRUCKS EXITING RIGHT / TRUCKS ENTERING RIGHT. Other studies have evaluated messages for emergency purposes []. Flooding emergencies that are likely to occur in a work zone due to construction activities were evaluated. The word FLOODED was evaluated; however, there was no consensus as to whether study participants would continue on the roadway or not []. Additional information needs to be provided, such as the specific location of the flooding or the exit to divert from the facility []. Sequential PCMS s For freeways, a maximum of seven words is recommended, and for facilities with speeds less than mph, a maximum of eight words is recommended []. If more information needs to be provided, the use of a sequential PCMS is recommended. The second PCMS should be placed 000 feet from the first. One study looked at the comprehension of sequential PCMS s and found: Including five units of information between the two PCMS s results in low comprehension rates Using four units of information results in the same comprehension as the same information on a Dynamic Message Sign Repeating one unit of information on both PCMS s can enhance comprehension []. Message Layout The MUTCD provides the standard that a PCMS shall consist of no more than two phases, containing no more than three lines of text per phase. The message shall be understandable regardless of the order being read. The messages shall be centered within each line of the legend []. Graphics A number of studies have looked at the addition of graphics to CMSs [] [] [] []. Overall, well designed graphics can aid in comprehension of a message, especially for nonnative language speakers and elderly drivers. Drivers prefer text over graphics that replace text; however, drivers respond quickly to graphic displays that replace text []. Graphics can also more easily describe complex situations that are hard to explain with text.
Susan Paulus 0 0 0 0 TYPICAL APPLICATIONS Some state guidance and national research include typical PCMS applications. Those that are currently documented are summarized in this section. Speed Management Speed management refers to situations where a reduced speed is desired due to hazards, work zones, adverse weather, incidents, or congestion [] [0]. Applications are temporary in nature, so PCMS s are ideal for these situations. In work zones, speed management may be considered when there is a high incidence of speeding drivers, high speed variance, high number of rear end crashes, or change in conditions within the work zone []. General guidelines include [] []: Provide a reason for the reduced speed Limit safety messages Use PCMS for speed reduction and enforcement Use in work zones greater than,00 feet in length Place PCMS 00 to 000 feet from the hazard within the work zone Do not place PCMS in high demand areas (tapers, interchanges, etc.) Show speeds of vehicles passing by Monitor and display real time conditions downstream Show current information about speed limits, delays, or construction Another study found the addition of graphics aided in reducing vehicle speeds by up to percent []. Inattentive Driving Inattentive driving is a problem in work zones and can have severe consequences []. PCMS s demand higher attention than regular static signage; therefore, they bring attention to the unique situation ahead. PCMS s should be considered to reduce inattentive driving in work zones with the following characteristics: greater than one mile in length, locations of unexpected queues, challenging or unique situations, or easy to miss maneuvers []. Demand Management PCMS s may be used in work zones for demand management; these situations typically include heavily traveled work zones (where peak demand exceeds capacity) or where queueing is expected that will impact traffic and/or the construction schedule []. California implemented this method by using existing roadway sensors to monitor traffic traveling through an I- work zone []. By providing users with information via CMS s in advance of decision points, the maximum delay was reduced from 0 minutes to minutes during construction. The messages provided on the CMS s considered both the construction roadway as well as alternate routes. Detour information was only provided when available detour routes had additional capacity. Advanced Notice Advanced notice on PCMS s involves making the public aware of a road, lane, or ramp closing in advance of the closure. ODOT recommends limiting the display of this information to drivers to two weeks before the closure takes place []. Minnesota Department of Transportation developed more specific guidelines based on the type of closure, time of closing (weekday vs. weekend), duration of closure (long-term vs. short-term) [0].
Susan Paulus 0 0 WORK ZONE PCMS RECOMMENDATIONS This section presents recommendations for PCMS use in work zones. The recommendations are tailored to current practices in Wisconsin but consider all the national guidance available. These recommendations can be used by design and construction engineers throughout the U.S. to ensure consistent messages. Advanced Notice of Closures Advanced notice of closures refers to the full or partial closure of a facility. Recommendations are shown in Figures and. System Ramp Closures For system ramp closures, place the PMCS along the ramp in which the message applies. During the actual closure, a PCMS should be placed to alert drivers of the closure and provide alternative route information. If the detour is before the driver reaches the closed ramp, provide a PCMS 0. miles before the detour or alternative route exit. If the detour is after the closed ramp, place a PMCS near the closed ramp. Service Ramp Closures For service ramp closures, place the PMCS along the ramp in which the message applies. If detours are provided, follow the System Ramp Closure guidelines above. For PCMS s on nonfreeways, the sign should be placed 00 to,000 feet advance of the preferred detour route. Roadway Closures For roadway closures, place the PCMS at the point of closure. During the actual closure, a PCMS should be placed to alert drivers of the closure and provide alternative route information. Provide a PCMS 0. miles before the detour route. An additional PCMS may be placed further upstream if capacity is expected to be exceeded on the detour route and other alternative routes are available. Lane Closures Under usual circumstances, PCMS s will not be used to give advanced notice of lane closures. Exceptions may include sporting events, holiday weekends, and other high traffic events in which some traffic may divert to alternative routes if they are aware of closures.
Susan Paulus System Ramp Closure Type Continuous Closure days or greater Continuous Closure days or less Nightly or Daily Closures Weekend Closures Service Ramp Closure Type Continuous Closure days or greater Continuous Closure days or less Nightly or Daily Closures Detour Type None Posted or Preferred Advanced Notice days days days 0 days (begin Thursday before) Advanced Notice 0 days to days to days Signed Detour (upstream of closure) Signed Detour (downstream of closure) Example Message LONGTERM Example Message Example Message D 0 EB D US 0 EB D I NB D D APR MAY FRIDAY OCT PM Phase Length (sec) / / APR - / NIGHTLY PM-AM / FRI PM MON AM APR MAY / Phase Length (sec) / APR - / NIGHTLY PM-AM / USE ALT ROUTE USE CTH BB USE BB Phase Length (sec) / / / USE NEXT / EXIT USE WIS / FIGURE Recommended PCMS Messages for Ramp Closures.
Susan Paulus 0 Roadway Closure Type Continuous Closure days or greater Continuous Closure days or less Nightly or Daily Closures Detour Sign Location At Closure Advance of Closure Advanced Notice 0 days to days to days Example Message ROAD ROAD ROAD ROAD Example Message ROAD D ROAD D MILE FREEWAY D AHEAD ROAD D AT US APR MAY Phase Length (sec) / APR - / NIGHTLY PM-AM / MON-THUR PM-AM / EXIT RIGHT ----> Phase Length (sec) / FOLLOW DEUR / EXPECT DELAYS / USE ALT ROUTE FIGURE Recommended PCMS Messages for Roadway Closures. Advanced Warning Advanced warning applies to a number of different situations. PCMS s can be used to enhance an existing static sign after a configuration change, provide a time-specific warning, or provide a warning about an on-going event. Recommendations are shown in Figures and. Another advance warning situation is for rolling slowdowns. Typically, minimal advanced notice is given to the public before a rolling slowdown. A PCMS should be placed before the start of the rolling slowdown at a distance that encompasses the expected queue length. Other PCMS s should be placed along the route to ensure traffic is aware of the slowdown. The zipper merge or dynamic late merge is a strategy directing drivers to stay in their lane until the merge point, which has been shown to increase capacity at the merge. PCMS s are used in real time to show messages when queueing is detected. When there is no queueing, the PMCS s should remain blank. /
Susan Paulus Advanced Warning Type Traffic Pattern Change Traffic Shift New Signal Location of PCMS 00 to 000 in advance 00 to 000 in advance Beyond expected queue Time Period to Display days days days Example Message NEW TRAFFIC PATTERN TRAFFIC SHIFTS RIGHT SIGNAL AHEAD X MILES BE PREPARED SP Phase Length (sec) / Work in Lane Closure Paving in Adjacent Lane Flagging Truck Egress/Access 00 to 000 in advance 00 to 000 in advance Beyond expected queue 00 to 000 in advance During Night Work During Work During Work During Work WORKERS IN ROAD AHEAD PAVING NEXT X MILES FLAGGER AHEAD TRUCKS ENTERING RIGHT SLOWDOWN IN WORKZONE WORKERS ON RIGHT PREPARE SP ON RIGHT TRUCKS EXITING / / / / Rough Road Flooding Advance of alternative route Advance of alternative route During Event During Event ROUGH ROAD MILE ROAD FLOODED AT US 0 USE NEXT EXIT / Rolling Slowdown Rolling Slowdown Advance of Slowdown Advance of Slowdown During Event During Event SLOWED TRAFFIC AHEAD SLOWED TRAFFIC XX MPH NEXT XX MILES DO NOT PASS / / Zipper Merge At merge point During Event MERGE HERE TAKE TURNS / Zipper Merge Zipper Merge Ahead of merge Advanced warning on other facilities During Event During Event USE ALL LANES I- WESTBND FIGURE Recommended PCMS Messages for Advanced Warning ( of ). DO NOT / MERGE BACKUPS AHEAD /
Susan Paulus 0 Speed management refers to situations where a reduced speed is desired and tools are used to measure vehicle speeds as they pass through the work zone. Typical applications include as drivers enter a work zone or within a reduced regulatory speed segment. PCMS s can be used to display real time information about travel times, delays, queues, or other traffic impacts. These messages can be generated from a contractor-supplied system or from incorporation into the existing detection. Additionally, messages could be used at specific times of the day when queues are expected that would not be anticipated by road users. Advanced Warning Type Speed Management Speed Management Speed Management Speed Management Real Time Travel Time Main Route Real Time Travel Time Alt Route Real Time Travel Time Comparison Real Time Queuing Anticipated Queuing Slowed Traffic Event Traffic Location of PCMS 00 to 000 in advance of hazard 00 to 000 in advance of hazard 00 to 000 in advance of hazard 00 to 000 in advance of hazard Advance of an alternative route Advance of an alternative route Advance of an alternative route to miles in advance of end of queue mile in advance of end of queue ½ to mile in advance Advance of alternative route Time Period to Display During Work During Work During Work During Work While delays are present or continuously While delays are present or continuously While delays are present or continuously During queueing During anticipated queueing During expected or measured During Event Example Message YOU ARE SPEEDING YOUR SPEED IS XX MPH YOUR SPEED IS XX MPH YOU ARE SPEEDING MINS I- MINS I- VIA 0 MINS I- SPPED TRAFFIC X MILES SLOWED TRAFFIC MILE LFT LANE NARROWS 00 FT EVENT TRAFFIC MILES Phase Length (sec) SLOW DOWN / SLOW DOWN / THANKS FOR NOT / SPEEDING MINIMUM FINE $XXX / USE ALT ROUTE MINS I- VIA 0 / / EXPECT DELAYS / LEFT LANE D FIGURE Recommended PCMS Messages for Advanced Warning ( of ). / SLOWED TRAFFIC / AHEAD EXPECT DELAYS /
Susan Paulus ACKNOWLEDGMENT Dr. David Noyce provided valuable direction and oversight in completing this work for an independent study course at the University of Wisconsin-Madison. REFERENCES Wisconsin Department of Transportation, "Facilities Development Manual," Wisconsin ] Department of Transportation, Madison. Wisconsin Department of Transportation, "Traffic Guidelines Manual," Wisconsin ] Department of Transportation, Madison. Wisconsin Department of Transportation, State of Wisconsn Standard Specifications for ] Highway and Structure Construction 0 Edition, Madison: Wisconsin Department of Transportation, 0. Wisconsin Department of Transportation, State of Wisconsin Standard Specifications for ] Highway and Structure Construction 0 Ediition, Madison: Wisconsin Department of Transportation, 0. D. Castleberg, Interviewee, Construction Standards & Publications Supervisor. [Interview]. ] December 0. Federal Highway Administration, "Manual on Uniform Traffic Control Devices," Federal ] Highway Administration, 00. Federal Highway Administration, "Portable Changeable Message Sign Handbook," Federal ] Highway Administration, 00. American Traffic Safety Services Association, "Guidance for the Use of Portable ] Changeable Message Signs in Work Zones," U.S. Department of Transpotation, 0. Indiana Department of Transportation, "INDOT Guidelines for Portable Changeable ] Message Signs (PCMS)," Indiana Department of Transportation, 0. Michigan Department of Transportation, "Portable Changeable Message Sign Guidelines," 0] Michigan Department of Transportation, 0. "Oregon Portable Changeable Message Sign Handbook," Oregon Department of ] Transportation, 0. Minnesota Department of Transportation, "0 CMS Manual of Practice," Minnesota ] Department of Transportation, 0. New York State Thruway Authoritt, "Guidelines for Use of Variable Message Signs ] (VMS)," New York State Thruway Authoritt, 0. Florida Department of Transportation, "Plans Preparation Manual," Florida Department of ] Transportation, 0. A. Clark, J. Wang, V. Miaer-Speredelozzi and C. Collyer, "Assisting Elfer Drivers' ] Comprehension of Dynamic Message Signs," Washington, D.C., 00. M. A. Flak, M. Jackson, W. Sorenson and A. Garms, "Comprehensive USe of Semi- ] Permanent Dynamic Message Signs for Regionwide ATIS Programs," Washington, D.C., 00. S. Hesar, J. Wang and C. Collyer, "Adding Graphics to Dynamic Message Sign Messages," ] Washington, D.C., 00.
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