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Vollmer Associates LLP. E-Z Pass Evaluation Report. August 2000.
Keywords: safety, signage
Methodology:
Vollmer Associates LLP was retained by the Federal Highway Administration (FHWA) to evaluate the success of the E-Z Pass implementation program on the New York State Thruway. This study reviewed short and long term policy goals and the anticipated costs and benefits of the E-Z Pass implementation program. An analysis of the changes in traffic volumes, travel patterns, frequency of trips and the total number of accidents were conducted at five tolled locations on the New York State Thruway and the actual results were compared with the anticipated results associated with the E-Z Pass implementation process.
The five analysis locations selected included the Tappan Zee Bridge and Buffalo City mainline barrier toll plazas and Interchanges 16 (Harriman), 24 (Albany) and 49 (Depew) tolled ramps on the controlled system.
In addition, an analysis was conducted to determine the success of the signage regarding the E-Z Pass system on the Thruway. This analysis primarily consisted of discussions with Thruway personnel, violation rates and anecdotal data from Thruway users.
Results:
According to the accident data from 1992 through 1998 obtained from the New York State Thruway, out of the total number of accidents at each of the five locations the percentage of E-Z Pass related accidents increased at each location analyzed. However, the increase at each location was lower than the increase in overall E-Z Pass usage at those locations. In general, the number of accidents per 1,000,000 transactions decreased at most locations, suggesting that E-Z Pass implementation did not result in an increase of total accidents.
As far as signage is concerned, there is a general consensus that the E-Z Pass signage is clear and easily understood. According to the New York State Thruway Authority (NYSTA), the violation rate in 2000 was just over one percent for E-Z Pass lanes compared to the five to ten percent rate for all other toll facilities.
Initially, two alternatives to E-Z Pass signing were reviewed. One option involved the installation of variable message signs on top of the toll plaza canopy and in advance of the toll plaza. The second alternative involved the installation of Manual of Uniform Traffic Control Devices (MUTCD) approved signs that were color coded and contained logos specific to the payment options available when entering the toll plaza. Although different in color and logo, each of the signs was uniform in size. The latter alternative was ultimately selected.
Drivers generally encounter signs approximately one to 1 ½ miles from the toll plaza. The group of signs indicates the type and location of the payment lanes. For most of the barrier plazas on the Thruway, the configuration is such that the signs read: Exact Change Only – Left Lanes, E-Z Pass No Cash 5 MPH – Center Lanes, and Cash Receipts – Left Lanes.
The second group of signs are encountered approximately ½ mile to ⅓ mile after the first group. These signs provide information on the price of and the distance to the toll. For example, a sign would read: Tollbooths ½ Mile – 40¢. Within the last ½ mile of the toll plaza, individual message signs are installed on the roadside indicating the location of each lane payment type. Variable message signs on the toll plaza canopy indicate whether the lanes are opened or closed and in which direction the traffic is flowing (for reversible lanes only).
In addition to the signage, flashing yellow lights have been installed above the E-Z Pass lanes which have further reduced weaving and violations. It should be noted that studies at the Spring Valley toll barrier indicated user confusion long after E-Z Pass was fully operational.
Klodzinski, Jack and Haitham M. Al-Deek. Evaluation of Toll Plaza Performance from Adding Express Toll Lanes at a Mainline Toll Plaza. Transportation Research Board 83rd Annual Meeting. November 2003.
Keywords: toll plaza operations
Methodology:
Data were collected at the University Mainline Toll Plaza on the Orlando-Orange County Expressway system prior to and after the addition of two ETC express lanes in each direction to determine the reduction in the level of delay at the plaza.
Prior to the plaza expansion there were a total of eight lanes with the two center lanes being reversible. Generally, five lanes were kept open in the direction of the peak period, leaving three available lanes in the opposite direction. While all lanes accepted ETC payment, the configuration in the peak direction usually consisted of two manual lanes, one automatic lane and two dedicated ETC lanes.
After the plaza expansion, none of the lanes were designated as reversible. Rather, there are six lanes in each direction consisting of two manual lanes, two automatic lanes and two dedicated express ETC lanes. The dedicated ETC lane speed limit was raised from 35 mph to 55 mph.
Cameras were mounted at various locations at and near the plaza to capture traffic upstream and downstream of the plaza. Roughly 30 hours of “typical” week day peak hour footage was recorded prior to and after the expansion of the plaza for a total of 60 hours. In addition, transaction data was obtained through detailed audit (DA) reports to evaluate lane throughput, speed, vehicle classification and the ETC participation rate.
The data collected was analyzed to compare measures of effectiveness prior to and after plaza expansion. The measures of effectiveness evaluated were throughput, vehicular delay (difference between plaza arrival and departure time), queue length, service time (time spent paying toll) and inter-vehicle time.
Results:
Overall throughput, measured in vehicles/hour (vph), increased slightly in the southbound direction and significantly in the northbound direction. This was due to a combination of increased speeds in the dedicated ETC express lanes as well as a decrease in ETC payment in the conventional lanes.
As a result of the plaza expansion, vehicular delay went from an average of 12 seconds in the automatic lanes and 15 seconds in the manual lanes to an average of six and eight seconds respectively. There were no delays in the ETC lanes.
The queue lengths were measured in vehicles/minute (veh/min). Prior to the plaza improvements, the average maximum queue observed in the automatic lane was nine veh/min and five veh/min in the manual lanes, regardless of direction. After plaza improvements the average maximum queue was three veh/min for both automatic and manual lanes. The average service time remained virtually unchanged in the conventional lanes from prior to and after the plaza improvements.
The inter-vehicle time is the difference between two consecutive vehicular departure times at the toll plaza at a specific lane. An overall average inter-vehicle time was derived by calculating the mean of all lanes for each lane type. The average inter-vehicle time for the ETC lanes was reduced by almost 50 percent as a result of the plaza improvements.
Mohamed, Ayman A.; Mohamed Abdel-Aty and Jack G. Klodzinski. Safety Considerations in Designing Electronic Toll Plazas: Case Study. ITE Journal. March 2001.
Keywords: toll plaza operations, safety
Methodology:
This study investigates the potential safety concerns occurring around toll plazas, with particular regard to varying payment methods and AVI technology. The Holland-East mainline toll plaza on the Orlando-Orange County Expressway Authority (OOCEA) system in Florida was chosen as the focus of the analysis due to the high number of toll transactions that occur there. At the time of the investigation, the plaza consisted of 14 lanes, five stationary lanes in each direction and four reversible center lanes. Analysis of the Holland-East Plaza occurred under the following four stages of development.
Three-and-a-half years of crash statistics compiled by the OOCEA were reviewed and categorized into four classification types: merging and sideswipe collisions, queuing and rear-end collisions, speeding and hit-plaza collisions and pedestrian related accidents. In addition, potential conflict points were evaluated on the approach to the Holland-East Plaza. The identification of potential conflict points was based on several factors including the toll lane type, vehicle deceleration rates, final velocity, the number of toll lanes and the volume of cross traffic between the lanes. This identification process was based on a similar study done at the Holland Tunnel in New Jersey.
Results:
Between January 1994 and June 1997, roughly 32 percent of crashes on the OOCEA system occurred at the 10 mainline toll plazas, 46 percent occurred at the ramps and 22 percent on the mainline sections between plazas and ramps. The average monthly crash rate prior to E-PASS (ETC) implementation was roughly 3.5 crashes/month as opposed to 7.5 crashes/month one year after E-PASS implementation. Ten percent of the total crashes were related to the E-PASS system because they either involved an E-PASS vehicle or occurred in a dedicated E-PASS lane.
Out of the 10 mainline toll plazas, the Holland-East plaza has the highest percentage of crashes at roughly 70 percent. The crashes at this plaza account for over 21 percent of all crashes on the OOCEA system. The conflict points that were identified on the approach to this plaza specifically addressed merging, queuing and speeding vehicles.
Merging and sideswipe collisions increased during Stage 3 as a result of the introduction of a new toll payment method (dedicated E-PASS lane). This was due to increased weaving and merging as a result of an additional choice in lane type. However, as drivers became more familiar with the lane configuration of the plaza, merging and sideswipe collisions decreased during Stage 4.
An increase in rear-end collisions also occurred during Stage 3, though queuing decreased. This was primarily attributed to driver confusion as many users stopped in the middle of the dedicated E-PASS lane after realizing that the toll could not be paid through conventional payment methods. Rear-end collisions remained high even at the beginning of Stage 4. This was most likely due to the relative unfamiliarity of the E-PASS system in addition to a second dedicated lane.
Crash severity increased during Stages 3 and 4 as a result of higher speeds through the plaza. The estimated property damage rate was used to represent crash severity. The estimated property damage rate increase is directly related to the implementation of the dedicated E-PASS lanes, as vehicles do not have to stop when passing through the plaza. Hit-plaza (structure) collisions increased as well. This was primarily attributed to drivers misjudging the lane with of the dedicated lanes at higher speeds.
Though crashes involving pedestrians were not reported, the potential for risk is higher with AVI technology. Since E-PASS vehicles using the dedicated lanes are not required to stop at the plaza, plaza employees or any other pedestrians who exit their vehicles for whatever reason are at greater risk of being hit.
Recommendations:
It is recommended that the dedicated E-PASS lanes be moved to the far left of the plaza as opposed to the center of the plaza. This may reduce the number of sideswipe collisions. Since faster drivers typically stay to the left lanes, it is logical to locate dedicated ETC lanes which do not require drivers to stop to the left. In addition, non-E-PASS users would know that there are no lanes to the left of the dedicated lanes and would only have a choice to go to the right.
Another suggestion would be to provide a more gradual and longer diverge area on the approach to the plaza. If drivers diverge from three or four lanes to five or six onto a total of nine, it would provide a smoother transition through the approach.
Advance signing is another useful tool to inform drivers of which lane to use for what specific toll payment method. Variable message signs (VMS) mounted in advance of the plaza as well as on the plaza canopy could provide more organization in identifying payment methods, lane status (open/closed) and even expected delay. Pavement markings could also help to channel drivers, eliminating much of the weaving that occurs.
Wilbur Smith Associates. Toll Plaza Safety Study: Plaza 51, York Road East-West Tollway. November 1999.
Keywords: safety, toll plaza operations
Methodology:
Wilbur Smith Associates (WSA) examined the lane configuration of a “typical” toll plaza on the Illinois State Toll Highway Authority (ISTHA) system in order to determine the impacts on safety anticipated as ISTHA’s I-PASS program expands. Plaza 51, York Road, on the East-West Tollway was selected for the study location. At the time of the study Plaza 51 consisted of 20 lanes, nine in the eastbound direction (four manual, four automatic and one I-PASS) and 11 in the westbound direction (six manual, four automatic and one I-PASS).
The traffic volume in each toll lane and the vehicle class was recorded in five minute increments during “shoulder peak” hours of operation. In addition, average approach speeds at the plaza and lane changes were recorded as well. The observed data was then used in WSAs TOLLSIM model to calibrate existing plaza operations and to estimate plaza queuing and toll lane usage under two separate scenarios. One scenario simulated the existing conditions and the other evaluated 1998 conditions which assumed no I-PASS only lanes and an eight percent I-PASS participation rate. Finally, the original data and outputs from the TOLLSIM model were used as inputs into WSAs safety model, SAFESIM, to estimate the probability of conflict points directly related to accidents.
Data collected during the shoulder peak hours (10:00 AM – 12:00 PM and 1:00 PM – 3:00 PM) were used because most accidents occur during these periods. During the off-peak, traffic is light and the probability of a conflict occurring is low. During peak hours, lane changes are rare and occur at slow speeds because queues from the toll plaza extend back into the mainline upstream of the taper.
Results:
When compared to the 1998 pre-I-PASS conditions, the results of the analysis indicate that there is a 13 percent reduction in the probability of a conflict in the eastbound direction and an 11 percent reduction in the westbound direction with the implementation of an I-PASS only lane and increased I-PASS participation. The overall probability of conflict in either direction is higher on the departure side of the plaza than on the approach side. This is due to the fact that there are more lanes on the approach side than the departure side. As was estimated, the probability of conflict was highest during the shoulder peak hours.
Recommendations:
The following recommendations were made to further enhance safety in operations at Plaza 51:
Provide adequate signage prior to the entrance to the toll plaza to inform drivers in advance of exits immediately downstream of the plaza;
Investigate the possibility of providing a second I-PASS only lane in the center of the toll plaza;
Reconfigure the toll plaza to reduce sideswipe collisions; and
Provide a barrier on the I-PASS lane to prohibit drivers from making a lane change at the toll plaza into the conventional lanes. In addition, adequate warning signs should be posted in advance for drivers entering the plaza.
Abdelwahab, Hassan T. and Mohamed A. Abdel-Aty. Artificial Neural Networks and Logit Models for Traffic Safety Analysis of Toll Plazas. Transportation Research Record 1784: Paper No. 02-2270.
Keywords: toll plaza operations, safety
Methodology:
This study examines two different modeling approaches in determining measures of safety at toll plazas. One of the models is statistics-based while the other is an artificial neural network (ANN). ANNs can be further categorized into two architectures: Multi-Layer Perception (MLP) and Radial Basis Functions (RBF).
Accident reports from 1999 and 2000 for the Central Florida expressway system were used to construct a database for the analysis. The Central Florida expressway system consists of three state roads: SR 408, SR 417 and SR 528. The entire network contains 79 miles of roadway, 10 mainline toll plazas and 42 ramp plazas. Out of the 1,932 accidents that occurred for the combined years of 1999 and 2000, 23 percent occurred in the vicinity of a toll plaza.
After screening out the incomplete reports, a database of 725 vehicles (drivers) was created. Of those 725 vehicles, 43.6 percent were involved in an accident while approaching the plaza, 43.7 percent were involved in an accident at the plaza and 12.7 percent were involved in an accident while leaving the plaza.
The accidents were further categorized by a variety of measures including driver age, gender, license type, alcohol involvement, violation and whether or not the driver was an E-PASS user; vehicle type, point of impact, number of impacts and speed ratio (estimated running speed to posted speed limit); and the type of toll plaza (mainline or ramp) and road conditions/environmental factors.
Results:
The study revealed that a two-level nested logit model was the most suitable model for identifying probabilities of an accident location. The model elasticity values showed that plaza type, peak period, vehicle type and E-PASS use have the greatest affect on the likelihood of an accident occurring upstream, at or downstream of a toll plaza. E-PASS users have an 11 percent increase in the probability of being involved in an accident at the toll plaza.
The RFB neural network was the best model for analyzing driver injury severity. The results showed that older drivers have a higher risk of being injured in accidents than younger drivers and that female drivers have a greater chance of severe injury than male drivers. Overall, E-PASS users have the highest risk of being injured in an accident. Drivers in passenger cars are more likely to experience severe injuries than drivers of trucks.
Recommendations:
Based on the model results, the following recommendations suggest:
Lieberman, Edward; Dr. Jinil Chang and Barbara Andrews. Applying Microsimulation to Evaluate, Plan, Design and Manage Toll Plazas. TRB 2004 Annual Meeting CD-ROM. 2004.
Keywords: toll plaza simulation, safety
This paper examines the Generic Toll Plaza Simulation (GENTOPS) model as it relates to toll plaza operation and safety considerations. GENTOPS differs from other toll plaza simulation models in that it models free flow or “unchannelized” vehicle movements within the transition zones of the toll plaza while considering the surrounding highway network as well.
GENTOPS was designed to be integrated with the WATSim highway microsimulation model so that regional networks containing multiple toll plazas could be analyzed. GENTOPS assigns vehicles to booths using a “Utility Score” to identify the most attractive booth for each vehicle at the current time. A toll booth is identified as a potential candidate if it services the vehicle type and selected toll payment, is accessible from the vehicle’s plaza approach link and is compatible with the vehicle’s plaza exit link.
GENTOPS also provides several statistics that can be viewed as potential safety measures of effectiveness. One of these measures is the “Percent of Vehicle Movements that Exceed a Specified Heading.” This is a measure of lateral movement within the reception and departure areas of the toll plaza. Though there is no empirical evidence to support the theory, it is often argued that pronounced lateral movement increases the exposure of vehicles to side-swipe collisions. As a result, toll plaza managers frequently erect internal barriers to restrict lateral movements in the interest of safety.
A simulation of the Newburgh-Beacon Bridge toll plaza in New York State was conducted using the GENTOPS model. The model was calibrated based on inputs obtained from the NYS Bridge Authority to develop a base scenario. Once the base scenario was established, analyses of alternative toll both configurations were conducted to determine whether the existing configuration was optimal or could be improved. In addition, scenarios were evaluated in which there was an 80 percent E-Z Pass participation rate as opposed to the 60 percent rate at the time of analysis. Overall, nine alternatives were examined.
Results:
Based upon the model outputs, it was determined that the existing plaza configuration consisting of two E-Z Pass only lanes and six mixed use lanes (E-Z Pass and cash) under the current E-Z Pass participation rate at the time provided for the optimal operating conditions at the Newburgh-Beacon Bridge toll plaza. Likewise, the percentages of vehicles with pronounced lateral movement was much lower than in the other alternatives examined. At the 80 percent E-Z Pass participation rate, an alternative scenario in which a configuration of three cash only lanes and four E-Z Pass only lanes provided for an improvement in operating conditions and safety measures over the original configuration.
Lin, Feng-Bor. Delay Model for Planning Analysis of Main-Line Toll Plazas. Transportation Research Record 1776: Paper No. 01-0588.
Keywords: toll plaza simulation, delay
Methodology:
This paper examines an analytical delay model that can be used as an alternative to more complex toll plaza simulation models for the purpose of expediting the toll plaza planning process. The Institute of Transportation, Ministry of Transportation and Communications in Taiwan sponsored the development of a stochastic, microscopic simulation model, referred to as the toll plaza simulation (TPS) model, to calibrate and test the delay model presented in this paper. The delay model estimates total delay by accounting for extra travel time due to deceleration, toll paying, acceleration and time spent waiting in queue. The model is calibrated with simulation data and, for V/C ratios less than 1.4, can yield delay estimates within 10 percent of simulated values.
Recommendations:
It is recommended that the delay model be used for preliminary screening of alternative designs and operations. However, further investigation should be conducted to determine if the model can adequately estimate delay based upon field data.
Al-Deek, Haitham M.; Ayman A. Mohamed and Essam A. Radwan. New Model for Evaluation of Traffic Operations at Electronic Toll Collection Plazas. Transportation Research Record 1710: Paper No. 00-1519.
Keywords: traffic simulation, toll plaza operation, delay
Methodology:
The Transportation Systems Institute at the University of Central Florida developed a toll plaza simulation model (TPSIM). TPSIM is a stochastic object-oriented discrete-event microscopic simulation model. The model consists of three main modules. These modules are the data entry interface which allows for inputs representing the plaza geometry, traffic and toll lane characteristics, global parameters (speed, driver reaction time, etc.) and run specifications; the simulation logic and algorithms; and the model output consisting of measures of effectiveness such as throughput, queue length, delay and lane utilization. The model was verified by eliminating any flaws through debugging and minor modifications.
The model was also validated by comparing the outputs of a simulation of the Holland-East mainline toll plaza on the Orlando-Orange County Expressway to real-world observations. Data collection of the toll plaza was achieved by utilizing video cameras to capture queuing delay, service time, queue length and throughput. In addition, a distance-measuring instrument (DMI) was installed on five different vehicles that passed through the plaza during the morning peak hour. Specifically, the DMIs were used to measure each of the vehicles’ approach speed and desired acceleration and deceleration rates within the toll plaza area. A total of 35 runs were made (5 morning peak runs for 7 days) during the data collection process. In addition, 20 TPSIM simulations were run with different random number streams and the results were averaged for each 5-minute interval within the simulated hour. Comparisons between the model outputs and the plaza observations were made by examining throughput, average queuing delay and total queuing delay.
Finally, several simulation scenarios were conducted to investigate the impact of electronic toll collection (ETC) market penetration on the benefits of ETC technology. The base scenario was modified by increasing or decreasing E-PASS market penetration in increments of 10 percent. To accommodate the increase in the volume of E-PASS vehicles, additional dedicated E-PASS lanes were introduced to the left of the two existing E-PASS lanes in the base scenario. Throughout the analysis, the proportion of automatic payment vehicles remained fixed at 20 percent. The introduction of a new dedicated E-PASS lane was achieved by converting one of the existing manual payment lanes into an E-PASS lane.
Results:
The findings of this analysis indicate that the benefits of E-PASS operation are sensitive to the plaza configuration. Adding more E-PASS lanes without an increase in E-PASS participation could cause an increase in total plaza queuing delay. However, regardless of the plaza configuration, total plaza delay can be reduced by 50 percent if 10 percent of the vehicles switch from the manual payment lanes to E-PASS lanes.
Recommendations:
In addition to the applications examined in this analysis, it is suggested that the TPSIM model also be use to determine the optimal configuration in toll plaza design, tollbooth scheduling and in finding the best lane arrangement to increase plaza efficiency during off-peak hours.
Stammer, Jr., Robert E. and David R. McDonald, Jr. Tollway Sign and Pavement Markings – Recommended Design Guidelines. Transportation Quarterly. Vol. 54, No. 3. Summer 2000.
Keywords: toll plaza design, signage, pavement markings
Methodology:
The intent of this research was to present a set of proposed design standards for toll facilities in the absence of any official design guidelines. This analysis expanded upon earlier efforts to develop toll plaza design standards by examining the increasing use of electronic toll collection (ETC) facilities. The authors of this paper gathered input from toll agencies and consulting firms from 14 states and the Commonwealth of Puerto Rico.
The authors reviewed several elements of toll plaza design such as: pavement markings, lane channelization, plaza island extensions, word and symbol markings and signage. After comparing the design plans obtained from the different agencies/consultants with the Manual on Uniform Traffic Control Devices (MUTCD), design guidelines were created for toll facility pavement markings and signs. These guidelines were presented to the panel of toll experts for review and comment, and recommendations were made based upon the responses.
Results:
Of the three methods of lane channelization presented to the panel, full channelization was preferred. Full channelization consists of pavement markings (striping) through the approach to each individual lane at the toll plaza. The panel recommended the addition of reflective pavement markers as well. With the exception of reversible lanes (which are yellow in color), all line colors should be white. The panel also recommended that solid white lines be used to designate dedicated or express ETC lanes in order to minimize the number of lane changes at these areas.
There was little consistency among the toll agency design plans regarding toll plaza island extensions. The majority of the panel agreed with the suggested island extension design guidelines developed by the researchers. The design recommended a minimum approach length of a 50 foot striped gore with an additional 0 to 25 foot solid line extending from the “V” at ramp plazas and a minimum of a 100 foot striped gore with an additional 25 to 100 foot solid line at mainline plazas. On the departure the gore would be 50 ft and 100 ft at ramps and mainline respectively. All striping would be in white unless it was for a reversible lane.
An overwhelming majority of the panel were against the use of pavement word markings in toll plazas. The panel did not reach a consensus on any of the proposed symbols or ETC names presented by the researchers. One of the panel experts suggested that an official color of ETC be established. As far as signs are concerned, the MUTCD states symbols are more advantageous than words. However, public education would be required for any national toll symbol. It was agreed upon that when using text, the message should be brief and the lettering should be legible.
McDonald, Jr., David R. and Robert E. Stammer, Jr. Contribution to the Development of Guidelines for Toll Plaza Design. Journal of Transportation Engineering. May/June 2001.
Keywords: toll plaza design
Methodology:
The intent of this research was to present a set of proposed design standards for toll facilities in the absence of any official design guidelines. This analysis expanded upon earlier efforts to develop toll plaza design standards by examining the increasing use of electronic toll collection (ETC) facilities. The authors of this paper gathered input from toll agencies and consulting firms from 14 states and the Commonwealth of Puerto Rico.
The authors reviewed several elements of toll plaza design such as: lane configurations, queue area, taper rates, transition lengths, lane widths and vertical geometrics. After comparing the design plans obtained from the different agencies/consultants with the Manual on Uniform Traffic Control Devices (MUTCD), design guidelines were created specific to toll facilities. These guidelines were presented to the panel of toll experts for review and comment, and recommendations were made based upon the responses.
Results:
After surveying several toll agencies, it was found that ETC express lanes are generally implemented in sets of two lanes, side-by-side and in the same direction, and operate at speeds in excess of 60 mph. In the case of dedicated ETC lanes, one or more are typically implemented in each direction of travel and are assigned speed limits that range between 15 to 45 mph. All ETC lanes are generally separated from the conventional lanes by some form of concrete barrier. A majority of toll professionals recommended a lane configuration of express or dedicated ETC lanes on the left, automatic coin machine and ticket lanes in the middle and manual lanes on the right; with the ability to pay by ETC in all lanes.
Allowing for express traffic on the left is more difficult when there are reversible lanes present. Based on the panel’s response to several proposals, the following guidelines were recommended for plazas with reversible lanes.
There are two methods of design for establishing the length of the queue area. One method is to allow queued vehicles to “stack up” in the approach taper. The other method is to design the queue area to accommodate the entire queue and use the approach taper for any overflow when design traffic volumes are exceeded. The majority of panel members agreed upon a method of a manual lane requirement calculation, lane number adjustment and validation via a simulation model for determining the minimal queue area.
A proposed set of toll plaza approach taper rates for conventional lanes were created by modifying taper equations published in the 1993 Revision to the MUTCD. A majority of the members of the panel agreed with the recommendations. Two modifications were suggested for the proposed approach taper rates. One modification would allow for reduced taper rates at higher speeds due to physical project constraints, such as a lack of sufficient right of way. The other modification was to establish a minimum taper rate of 10:1 for all speeds ≤ 30 mph.
A set of departure (merge) taper rates were also proposed for vehicles exiting the toll plaza. These proposed rates were met with a 90 percent approval rate by the panel. For areas where vehicles are not anticipated to stop (express/dedicated lanes), it was recommended that equations presented in the 2000 MUTCD and the “Green Book” (A Policy on Geometric Design of Highways and Streets) be used for lane additions or subtractions.
Proposed design standards regarding lane widths, pavement cross slopes, profile grades and sight distance for the different lane payment types were developed from a variety of design guide publications such as the MUTCD and the Green Book. The panel responded to these recommendations with mixed opinions, but the majority agreed with the proposed guidelines. In many instances, the guidelines presented in the Green Book were altered only slightly to accommodate toll plaza features, or in the case of sight distance considerations, they were not changed at all.
Recommendations:
The majority of toll experts that served on the panel agreed with the proposed guidelines developed through this research. Most of the members indicated that they favor a national standardization of ETC; however, more so on a regional level. They also indicated a desire for the continued use of ticketing equipment and automatic coin machines in order to maintain payment flexibility.
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