Wilbur Smith Associates (WSA) organized an Expert Panel workshop on August 17th and 18th, 2004 in Lisle, Illinois. The workshop is one element of the Federal Highway Administration (FHWA) sponsored study on “Traffic Control Strategies at Toll Booth Plazas”. The WSA Team for this project also includes Post, Buckley, Schuh & Jernigan (PBSJ) and Terry Geohegan, a subconsultant to WSA.
The objectives of the study are to review current practices and develop guidelines for designing traffic control devices for toll plazas that inform drivers which lanes to use for specific methods of payment, to reduce speed variance, and minimize lane changing. The goal is to have a consistent strategy to accommodate the mix of non-stop traffic and stop-and-go traffic in retrofitted conventional toll facilities. This requires identifying and handling the potential points of conflict at toll plazas so that safety and operations are enhanced, better efficiency and economy of design are achieved, and motorist recognition and comprehension are improved. A major objective of the study is to create consensus agreement among the toll agencies to ensure use and ideally, adoption of the design guidelines developed by this project.
Prior to the workshop, the WSA Team developed a detailed survey addressing design considerations for toll plazas, specifically focused on the placement, design and usage of traffic control devices. The survey also addressed geometric design and operational aspects of toll plazas as they relate to traffic control strategies employed by agencies. Express Electronic Toll Collection (ETC), Dedicated ETC, Automatic Coin Machine/Automatic Ticket Issuing Machine, and Manual Toll Collection toll lanes were addressed in detail by the survey. The survey was designed for completion on-line, hosted on the Wilbur Smith Associates corporate website, and toll agencies were notified of the survey in early May 2004. Toll agencies were provided instructions on how to complete the survey, as well as a detailed “Terms and Definitions” document.
The WSA Team analyzed the survey and distributed the results to all participants and observers prior to the workshop. The survey results and summaries of selected design elements were provided at the workshop. These materials, together with a brief program, were used as the basis for the Expert Panel workshop discussions. The WSA Team also prepared a presentation on toll plaza signing, hardware and equipment to illustrate the variety of usage and serve as a basis for initiating the discussion. The Expert Panel consisted of seven panel members, four team members, and observers from FHWA and the International Bridge, Tunnel and Turnpike Association (IBTTA). Panel members were selected to represent a wide range of experience and toll facilities. The size of the panel was intentionally limited to a small number to ensure in-depth discussion of the issues outlined in the program. The workshop was moderated by Glenn Havinoviski, the WSA Project Director. The participants in the workshop are listed below.
Terry Geohegan (Bader & Geohegan)
David McDonald (Hanson Prof. Svcs.)
Greg LeFrois (HNTB)
Michael Davis (PBSJ and Florida Turnpike)
Sam Wolfe (Indiana Toll Road)
Kerry Ferrier (Ohio Turnpike Commission)
Roxane Mukai (Maryland Transportation Authority)
Glenn Havinoviski (WSA)
Raghu Kowshik (WSA)
George Scheuring (WSA)
Phil Miller (PBSJ)
Linda Brown (FHWA)
Neil Gray (IBTTA)
The workshop was divided into four sessions, each focused on a particular topic area. The following session topics were selected prior to the panel discussion based on anticipated impact on toll plaza operations and safety:
Session A: Signing, Pavement Markings & Channelization
Session B: Lane Configuration/Plaza Operations and Safety
Session C: Geometric Design, Attenuators, Safety Barriers
Session D: Manual, ACM/ATIM, ETC Equipment Implementation
Introduction and Study Objectives
The workshop began with introduction of the participants, project team members and observers. Following the introductions, WSA’s Project Director, Glenn Havinoviski, described the overall objectives of the study. Linda Brown, FHWA’s Project Manager, then described the intended outcome of the study. Ms. Brown indicated that FHWA would like to develop a section of the Manual on Uniform Traffic Control Devices (MUTCD) addressing traffic control devices for toll facilities by 2005-6. She indicated that the best practices and guidelines for toll plaza traffic control device design and implementation developed in this study would provide input into the new section of the MUTCD.
Several panel members asked whether the intent of the study was to provide traffic control device guidelines for new toll facilities, or whether the guidelines would also apply to existing facilities. The WSA Team responded that while the design guidelines would be most easily adopted when designing new facilities, they could also be adopted by toll agencies when retrofitting or rebuilding existing toll plazas. The WSA Team further explained that toll agencies would not be expected to immediately conform to the best practices and design guidelines produced by this study. Rather, the product of this study would serve as a guide for agencies to voluntarily adopt when they rebuild or retrofit existing facilities. In addition, WSA indicated that when a section is added to the MUTCD addressing toll facility traffic control devices, there would typically be a period within which agencies would be required to comply. It was generally agreed that the design guidelines produced by this study would focus on new installations, although agencies should strongly consider using the recommendations as guidelines when retrofitting existing facilities.
The WSA Team then presented a compilation of photographs from various agencies to illustrate the variety of signing and other traffic control devices used at toll plazas.
Session B: Plaza Operation and Lane Configuration
It was suggested that the panel begin by discussing plaza lane configuration and layout (Session B) before discussing plaza signing, pavement markings and channelization (Session A). The WSA Team explained that plaza operation/lane configuration issues (such as whether similar payment types are grouped or vary based on traffic demand) often dictate the types and placement of traffic control devices. Grouping lanes by payment type, and the location of these lanes at the plaza (e.g. grouping non-stop ETC lanes on the left of the plaza) allows advance signing to orient drivers further away from the plaza. However, several agencies vary the number of lanes of a specific payment type, their location at the plaza, and vehicle types permitted to accommodate varying traffic demands. The types and location of traffic control devices to address these situations will differ from those used when lane configurations do not vary.
The panel then took up the issue of grouping of lanes and the placement of non-stop ETC lanes at the plaza. Discussion first focused on Express ETC lane plazas. Some panelists asked what constitutes an Express lane plaza. The WSA Team responded that these lanes are typically non-stop ETC-only lanes that operate at highway speed, are separated from the conventional toll plaza lanes by a barrier (such as concrete wall or earth berm), and the plaza canopy does not usually extend over these lanes. The panel indicated that there is a need to standardize the terminology used to describe various plaza types. Discussion focused on the location of Express ETC lanes, with the consensus being that as a general guideline Express ETC lanes be placed on the left side of mainline plazas, when constructing new plazas. It was recognized that this recommendation might not apply to retrofitted plazas. Some panelists also indicated that the placement of Express lanes on the left permits the area separating the Express and conventional lanes to be used as a staging area for enforcement vehicles. One panelist indicated that trucks are not permitted in their Express lanes. This restriction exists due to the need to perform security checks on trucks prior to entering bridges and tunnels. Another panelist indicated that at ramp plazas, Express ETC lanes are provided on the right of exact-change coin machine lanes. This lane configuration protects toll plaza workers who have to service the coin machines, by keeping the workers away from the non-stop traffic.
Dedicated ETC lane configuration was discussed next. The panel concluded that, as a general guideline, it is recommended to keep faster moving traffic to the left of the plaza, consistent with typical highway speeds, and to minimize the amount of weaving needed to access plaza lanes. In addition, the panel recommended that grouping lanes of similar payment types together is preferable. Some panelists noted that the location of the plaza administration building also influences the placement of lanes. The recommendation of the panel was to provide a lane configuration that minimizes the number of lanes of live traffic that toll plaza workers have to cross to reach toll booths, or to service equipment.
The discussion then turned to how best to provide advance warning to drivers of toll plaza lane configuration, what types of payment are accepted, whether the lanes are open or closed, distance to the toll plaza, speed restrictions through toll plaza lanes and toll rates. Panelists also noted that the information provide to drivers could also include the use of tokens/tickets, and whether ETC is accepted in every lane etc. It was noted that some agencies have not installed ETC in every lane due to funding limitations. The general recommendation was that it was desirable to provide ETC in all lanes.
Session A: Signing, Pavement Markings and Channelization
Toll Plaza Sign Placement and Message Content
The discussion of toll plaza signing began with a general discussion of the factors that should be considered. The WSA Team listed the basic elements that influence motorist understanding of signing including: visible elements, such as the lane types and plaza; invisible elements, such as payment types accepted, toll amounts; and, user elements, such as driver familiarity. The WSA Team stressed that the driver population consists of commuters or frequent users of the facility who do not need to always read the sign, and tourists or infrequent users, who need significantly more information. The WSA Team suggested that there is a need to provide signing for the unfamiliar traveler, since even though these drivers represent a small proportion of users, they can have a significant impact on toll plaza operation and safety by making last-minute lane changes/choices or by stopping in non-stop lanes. The MUTCD requirements for Freeway Guide Sign spacing was raised as a possible starting point for the discussion of toll plaza advance sign placement.
The MUTCD recommends that advance guide signing for major/intermediate freeway interchanges be provided at distances of 2, 1 and ½ mile from the interchange. The advance sign at the 2-mile distance is optional, but recommended. For minor interchanges, the MUTCD requires advance signs at 1 and ½ mile distances from the interchange. In addition, the MUTCD recommends placing signs overhead when three or more mainline lanes exist in one direction, or at complex interchanges.
One panelist said that Florida provides a minimum spacing of 1000 ft between toll plaza advance signs. The discussion then turned to whether it is necessary to provide information on plaza lane configuration on all signs in advance of the toll plaza, or whether it is better to separate plaza lane configuration signing from toll plaza advance signing. Examples of toll plaza advance signing from Florida and Illinois were reviewed to determine the advantages and disadvantages of combining advance toll plaza signing with lane configuration signing. Combining lane configuration signing with toll plaza advance signing reduces the number of signs needed, and reduces sign clutter. However, this results in drivers having to absorb more information from each sign. The panel agreed that the first advance toll plaza sign should only provide information on the toll plaza ahead. The panel also concluded there was a need to separately address advance signing for Express lane toll plazas since signing needs to be provided for the divergence of express lanes from the mainline lanes that feed the conventional toll plaza. The panel discussion led to the following signing schemes for Express ETC lane and Conventional toll plazas.
Table 1 summarizes the panel’s recommended signing scheme for Express lane toll plazas. The panel recommended providing toll plaza advance signs at distances of approximately 2, 1 and ½ mile from the point at which the Express lanes and mainline lanes feeding the Conventional plaza diverge.
In addition, the panel recommended that the advance sign 2 miles from the divergence point be placed overhead. However, this sign could be installed as a ground-mounted sign on the side of the road. The 1 and ½ mile signs were recommended to be placed overhead. The distances of 2, 1 and ½ mile were chosen as desirable locations, although it was recognized that local conditions would dictate the specific placement distance of these signs from the divergence point. The panel recommended that providing toll rate information on the 2, 1 and ½ mile signs should be optional.
At the gore (i.e. the divergence point of Express and mainline lanes), it was recommended that overhead signs be placed that indicate the payment methods accepted in the Express vs. Conventional lanes. In addition, vehicle restriction information and lane use signs should be provided at the divergence point.
The panel recommended that, provided sufficient distance exists from the gore to the plaza canopy, a sign be placed a minimum of 800 feet from the canopy that provides payment methods accepted at various plaza lanes. This distance was selected to ensure that the sign did not obstruct plaza canopy signing. The panel also determined that providing lane-speed restrictions could be provided as an option on this sign.
Recommended information to be provided on canopy signing included: payment types accepted (ETC, exact coins, tokens, tickets, or change), vehicle restrictions, lane use messages (open/closed), and lane-speed restrictions.
Detailed toll rate information was only recommended to be provided on a toll schedule sign, placed close to the plaza. The optional toll rate information on the 2, 1 and ½ mile signs should only be provided as brief messages, with detailed toll rate information provided on the separate toll schedule sign.
Table 2 summarizes the panel’s recommended signing scheme for Conventional toll plazas. These toll plazas may include dedicated ETC lanes, although these lanes are not fully separated from the cash toll lanes. Vehicles using the dedicated ETC lanes approach the plaza together with cash-paying vehicles, and merge with the cash traffic after going through the plaza.
For the Conventional plaza, distances are measured from the plaza canopy. The panel recommended providing toll plaza advance signs at distances of approximately 2, 1 and ½ mile from the plaza. On the 2 mile sign, the panel recommended including messages warning of the toll plaza ahead, with optional toll rate information. Overhead sign placement was preferred, although ground-mounted roadside signs could be used instead.
The recommended placement of the 1 and ½ mile signs is overhead, with sign content composed of messages warning of a toll plaza ahead, the payment methods accepted, vehicle restrictions, and toll rate information as an option.
An optional sign was also proposed at a distance of ¼ mile from the plaza canopy that provides payment method/lane type information, lane use information (open/closed) and lane-speed restrictions. Payment methods/lane type and lane-speed restrictions messages are optional.
Design of Toll Plaza Signing
The panel also discussed issues of sign background colors, logos signifying ETC programs, diagrammatic signing, symbols and terminology typically used in toll plaza signing.
Advance signing to warn drivers of a toll plaza ahead varies from agency to agency. Examples reviewed by the panel included yellow-background “warning” signs, green “guide” signs, and white “regulatory” signs. Linda Brown indicated that guide signing could be used to inform drivers of toll plazas. However, the panel indicated that there is a need to distinguish toll plazas from interchanges. The majority of the panel recommended that advance signing for toll plazas use yellow-background warning signs.
The panel next discussed background colors for payment types. Some panelists indicated that their agency intends to use purple as the background color for ETC dedicated lanes. Linda Brown indicated that FHWA favors a white background for toll plaza payment-type signing, since customers are required to pay a toll, and the signs serve a “regulatory” purpose. Ms. Brown said that the type of lane (ETC/Exact Change/Manual etc.) could be designated by a supplemental plaque with a distinct color for each payment type. The panel concluded that specific background colors for the various payment types are desirable, although no consensus was reached as to what were the best colors. Candidate colors selected included white and purple for dedicated ETC lanes, although the panel recommended other colors also be evaluated. Some panelists questioned whether logos used on the purple background would be distinguishable during low visibility conditions such as dawn and dusk. One panelist suggested that different background colors for each payment type would provide better recognition/target value at greater distances, rather than using a single color (e.g. white) for all signs. This panelist suggested that white be used as the background color for dedicated ETC lane signing, since only drivers who are part of the ETC program are permitted to use these lanes, and they are often operated as non-stop lanes. In other lanes, drivers are typically required to stop and pay a toll, so the panelist suggested the signing use background colors different from the ETC lanes. The panel unanimously recommended that the red background used by some agencies for manual toll collection lanes not be used.
ETC logos are placed on advance and canopy signing by many agencies. The panel reviewed several different applications of ETC logos. In response to panelists’ questions, Ms. Brown indicated that FHWA would not require a national ETC logo. Aspects of ETC logos that panelists suggested should be addressed included size of the logo and contrast between the logo color and sign background. However, FHWA would like to standardize other aspects of toll plaza signing, such as symbols used to identify manual and exact-coin toll collection. Ms. Brown said that FHWA is currently conducting an evaluation of toll plaza signing and symbols under a “Pooled-Fund” study, and that the panel could recommend additional symbols for evaluation. Symbols representing “a toll attendants in a booth” and “a hand dropping coins into a basket” were recommended by the panelists for the Pooled Fund study.
Diagrammatic signs used by the Oklahoma Turnpike Authority (OTA) and Orlando-Orange County Expressway Authority (OOCEA) to convey the divergence of Express ETC lanes from the mainline lanes (Conventional Toll collection) were reviewed. The panel indicated a need to standardize diagrammatic signs, although no specific recommendation was provided.
The panel indicated that the terminology used in toll plaza signing needs to be standardized. Examples of terminology used to designate manual toll collection included: Cashier, Full Service, Attendant, Change/Receipts, Change, Cash/Receipts, Change Provided, and Manual. For exact change toll collection, examples included: Automatic, Exact Change, Exact Coins, and Coins Only. Similar examples were also reviewed for ETC toll collection. No consensus was reached on the terminology, and the panel concluded that additional evaluation needs to be conducted on this issue.
Pavement Striping and Channelization
The panel only discussed pavement striping and channelization with respect to guiding drivers into the lanes and preventing last-minute lane changing. The panel recommended the use of pavement striping and channelization/delineators only for non-stop lanes. The striping extends from the plaza for several hundred feet at some agencies to over a ¼ mile at others. The striping and channelization recommended is distinct from the “gore area” pavement markings used by many agencies to identify toll islands and attenuators.
Session C: Attenuators and Crash Blocks
Attenuator and crash block usage at toll agencies were discussed briefly. The variety of designs currently used were reviewed, with the following recommendations. Use of the “bull nose” crash block design was discouraged due to the potential for directing errant vehicles upward and possibly into a toll booth. The panel indicated that the attenuators used should conform to NCHRP 350 standards. In addition, the panel discussed what vehicle speed should be assumed when designing the attenuators: should the plaza approach speed limit be used, or should the mainline speed limit be used? Panelists commented that a drowsy driver may not slow down approaching the toll plaza, and the best approach would be to assume the operating speed of the mainline. One panelist indicated that Florida assumes a speed of 70 mph, based on the posted speed limit on the mainline.
The panel also discussed the use of two bollards (crash blocks) placed some distance apart upstream of toll booths. The reason for having separate bollards is to act as a vehicle trap – if a speeding vehicle hits the first and is launched upwards, the space between the bollards acts as a vehicle trap, capturing the vehicle before it reaches the toll booth.
Session D: Manual, ACM/ATIM and ETC Equipment Implementation
Lane Use Signals, Flashing Beacons, and Transaction Indicators
Panelists raised the issue of inconsistent usage of lane-use signals and flashers. Examples mentioned included the use of yellow flashing beacons next to lane-use signals/signal heads over the lanes. These flashing beacons are sometimes used both on the attenuators/crash blocks as well over the lane. The panel recommended that standard lane-use signals (MUTCD minimum size 18 inches) be used (only green down-arrow and red X), with signal heads as an alternative. If signal heads are used to indicate whether the lane is open or closed, the panel recommended that 12-inch diameter heads be used, and that only red and green heads be installed (no yellow head).
The panel recommended that flashing beacons not be installed together with the lane-use signal or signal-heads, as it provides contradictory information to drivers. In addition, the panel recommended that flashing yellow beacons could be placed on both sides of the canopy sign, or over the sign (not below the sign) only for dedicated ETC lanes, but not for other lane types. The purpose of the flashing beacon is to draw attention to the lane, but not to serve as a lane-use signal. The panel recommended that transaction indicator lights not be used in Express ETC lanes, although they may be installed in dedicated ETC and cash toll lanes. The panel felt that transaction indicator lights may unduly distract drivers in non-stop ETC lanes. However, the panel felt that feedback provided to drivers on account balance in non-stop ETC lanes does have some value. In exact change and attended lanes, the panel indicated that Red, Amber and Green signal heads or pedestrian type displays with messages such as STOP-PAY TOLL/THANK YOU may be used.
The panel also discussed the use of Stop signs in manual and exact change toll collection lanes. Examples of modified Stop signs were reviewed (e.g. with supplemental messages on the Stop sign such as “Pay Toll” and “Get Ticket”). Some panelists indicated that the limited space to place signing on the islands had necessitated placing the supplemental messages on the Stop signs. No consensus recommendation on the use of the modified Stop signs was provided. However, the panel indicated that a new section of the MUTCD could specify a modified Stop sign that included supplemental messages such as “Pay Toll” or “Get Ticket”. This new sign would be restricted for use only at toll plazas. The panel also discussed one agency’s practice of using a rectangular sign with the message “Stop/Pay Toll” using black letters on a white background. The panel recommended against using this sign.
WORKSHOP CONCLUSION AND NEXT STEPS
The preceding summarizes the discussions and recommendations of the Expert Panel on specific issues. The WSA Team indicated that a summary of the workshop would be provided to all participants for review and comment. Subsequently, a report on the state-of-the-practice and design guidelines will be prepared and distributed to toll agencies for review and comment.
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