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Task #1Seco11d Interim Report Simulation Modeling of Toll Plaza Traffic at Midpoint, Cape Coral, and Sanibel Bridges (CUTRAccountNo. 21-17-271-L.O.) prepare4 by Mark Burris Ramakrishna Apparaju Center for Urban Transportation Research College of Engineering-University of South Florida 42oi E. Fowler Avenue, CUT 100, Tampa, FL-33620 Ph: (813)974-3120, Fax: (813)974-5168 for the Lee County Variable Pricing Team October 15, 1997
Introduction The Lee County DOT is planning to ope n the Midpoint bridge in October 1997, and it is to be equi pped wi th Electronic Toll Collection (ETC) facilitie s Because of the additional traffic volumes to be served by the M i dpoi nt bridge traffic conges tion on the Cape Coral bridge may be signifi cantly reduced It is due to the anticipation that 37% of the traffic handl ed by the Cape Coral bridge will shift to the Midpoint bridge along with a large shift (63%) from other non tolled bridges. Lee County DOT also believes that these bridges will experience increased ETC partici pation by as much as 50%, once the ETC systems comes in to effect 1his report examines th e potentia l impact of several f actors on the traffic of t hree toll bridges in Lee Coun ty (Sanibel M idpoint, and Cape Coral bridge s ) T o accomplish this computer-based microsim ulation models developed previously for each of the toll plazas and their approaches have been modified by accommodating ne w lane configurations, traffic vo lum es, and toll payment options. The main factors examined in this t ask include: reversible lanes gates in the tolllaue s future traffic conditions dedicated ETC lanes Presently, during peak hours the Cape Coral bridge operates with six lanes in each direction and out of these, three lanes are for ACM and ETC vehicles, one is a reversible lane meant for ACM and ETC vehicles and two other lanes are for ACM and Manned vehi cles. However, it is believe d that the introdu ctio n of ETC system s will greatly reduce service times and average v e hicle delays of the vehic l es in the queue, the throu g hput of the toll lan es will increase signi ficantly, and the need for reversi b le l anes will be reduced, or eliminated This report looks at the impact of reversible lanes on the traffic by considering two scenarios: the implications without any re versib le lanes; and the effect of one reversible lane. Lee County DO T has decided to leave the existin g gates at the Midpoint, Cape Coral, and S anibel bridges due to the absence of any automated violation enforceme nt systems during the initial imp lemen tation period Howev er, t he presen ce of ga t es in the toll lane results in increased 2
service times, and may lead to queuing. This study also examines the impact of gates by using two s ub models: one with gates and another without gates T hese sub mode ls have also been examined with alternative reversible lane configurations This report also explores the impact of different lane configurations on the traffic. This has been accomplished by considering two scenarios; one with all mixed-use lanes; and another with one dedicated ETC lane in each direction and the other lanes as mixed-use lanes. As well as modeling current traffic conditions, this study a lso explored the impact of future traffic conditions in order to determine if any reversible lanes would be necessary in the future This is accomplished by simulating the predicted traffic conditions now and in the years 2001 and 2011 These future years have been chosen to correspond to the years used in previous modeling efforts Various scenarios modeled in this study have been presented i n Figure 1. I I Reversible Lane I Gates /,No Rei'OlSible Lanes I v. F 'uture (2001 I Re\'ersible Lane I an d 20 U ) HNo
Methodology Tttaffu: Data Used By using the methodology adopted our previous work (Task #I First Interim Report Sim ulation Modeling of Toll Plaza Traffic at Midpoin t and C ape Coral Bridges for November 1997, August 7, 1997), predicted traffic volumes in the peak direction during th e peak hour have been calculatedThey are shown in Table 1. Table 1: T raffic Volumes Modeled 1997 Cape Coral 2,366 2,42 4 2,6 1 6 Midpoint 1,676 2,000 3,07 8 Sanibel 1,000 1,100 1,300 Toll Payme n t Options In order to easily differentiat e among the various scenarios being studied, only one l eve l of ETC participation rate has been modeled. This rate is equal to the current sticker rat e of 50% To stu dy the impact of gates it is assumed that 40% of the users will have traditional ETC tag s and wi ll only ha v e to stop for the gate to be raised while I 0% of the users will have ETC with a coin drop (this soenario is similar to 40"/o of the vehicles with unlim ited stickers, and I 0% of the vehicle s using coin drop stickers ) ETC users who must stop for the gates t o raise wi.ll hav e similar transaction times as current full discount sticker users, and will be modeled as such. S imilar l y, in the model s w ithout gates, it has been assumed that 40% of the traffic will be traditional, n onsto p, ETC vehicles and I 0% of the traffic will be coin drop ETC users. The 4
following table shows the proportions of vehicles using various toll paymen t options. However, for Sanibel bridge, different proportions of participation rates have been assumed. This has been dQne keeping in mind the existing high participation rates of sticker patrons. The payment options modeled and proportions have been shown in Table 2. T able 2 : Percentage Users with Various Toll Payment Options With Gates Caqe Coral and Midpoint Sanibel Vehicles using unlimited stickers 40.00% 50.000/o V chicles using coin drop stickers 10.000 /o 10.000/o Vehicles with correct change 30.00% 5.000/o Vehicles using ETC tags 0.000/o 0.000/o Vehicles needing change 20.000/o 35.000/o W i t hout Gates Cgpe Coral and Midqoint Sanibel Vehi c le s using unlimited stickers 0.00% 0.00% Vehicles using coin drop s tickers 10.00% 10.00% Vehicles with correct change 30.000/o 5.00% using ETC tags 40.00% 50.00% Vehicles needing change 20.00% 35.00% Simulatwn Models To examine the impact of several factors on traffic conditions, five basic simulation models have been deve loped representing five different scenarios. They are: Model 1: Simulation model with 50%1 ETC patronage, with gates in the toll lan es, without reversible lanes, and without dedicated ETC lanes Model 2: Sunulation model with 50% ETC patronage, with gates in the toll lanes, with one reversible lane, and without dedicated ETC lanes l 60% for Sanibel bridge in all cases s
Mod e l 3: Simulation mo de l with 50% ETC patronage, wi th out gates in the toll lanes, without revers i ble lanes, and without dedicated ETC lanes Model4: Simulation model with 50% ETC patronage, without gates in the toll lanes, with one reversible l ane and without dedicated ETC lanes Model 5: Simulation mode l With 50% ETC patronage, without gates in the toll l anes, without reversible lanes, and with one dedicated ETC lane On the Sanibe l bridge tolls are c h arged going onto the island eliminating the potential for reversible Janes. Hence the Sanibel bridge has not been modeled with scenarios 2 and 4. The dedicated ETC models are developed in such a way that the ETC vehicles use the dedicated lan e until that lane becomes full and then the ETC vehicles will use the mi xed use lanes. This i s an important assumption, as all the ETC vehicles may not always opt for the dedicated lane in the real life. Tills may further reduce the benefits of having a dedicated ETC lane over what is m o deled here. Lane A r rangements The Jane arrange m ents m odeled in this study are shown in Figures 2, 3, a n d 4. Figure 2. Lane A rrangement on Midpoint Bridge . .. .. . :---: " 'C-t-ACM ETCtACN ETC+AC)f ETC A.CM ETCACM &TCMAI'I' :tTCMAN Re ver,ib1 c Lane Figure 3. Lane Arrangement on San i bel Bridge I.TC+ACM l!TC+MAN ETC+MAN 6 0 Q) 0
Figure 4. Lane Arrangement on Cape Coral Bridge . . -. . .. . .. : ..... ...... : 0 . TC+AC)f ETC .. A.CM ETC-t-MAI't ETC .. MAN 7 0 0 0 0 0
Simulation Modeling Results This section summarizes results from the nve models created and they are presented in Table 3 (Sanibel bridge), Table 4 (Cape Coral bridge), and Table 5 (Midpoint bridge). A number of . model runs have been perfonned with current and future traffic volumes . Vehicles been generated with five different arrival streams, arid their output have been av eraged to ensure random arrival results. Table 3: Simulation Model Run Results For Sanibel Bridge . 8 4.540 5.420 5.400 7.800 8.790 37.60 16.17 19.30 17.46 25.16 23.83 37.64 24:85 30.23 27.38 43:19 39.04 120.7 18.01 29.72 20.44 40.19 30.87 114.37 10.98 11.21 13.23 7.27 7.32 7.40
. Table 4 : Simulation Mod e l Run Result s Fo r C ape Coral Bridge . 9 13 13 15 20,2 8 20.08 21.19 29.74 31.04 34.44 25.00 25.31 28.65 17.53 17 .66 18.20 17.33 17.59 17..66 17.44 1 7 .13 17.7 1 16.24 14.50 14.80 . 13 14 16 20.56 20.8 5 22.40 27.66 2 8.47 3l.22 21.9:4 22.24 24.24 17 .96 18 : 14 19.28 18 .17 18.41 19.52 19.21 19.30 20.63 N f A NIA NIA 12 13 15 19.14 19.31 20.12 27.8 8 2 8.29 30.59 21.81 22.20 23.62 1 6.81 16.72 17.22 15.51 !'5.72 16.34 16.64 16.70 16.92 17.70 17.84 1 8 .25 1 8 21 45 27.45 31.2461.78 29.55 30.25 31.16 25.90 25. 9 1 27.44 41. 33 50.56 118 33 39.65 48.51 116 .79 13.98 14.10 14.27 N/A N / A N / A ..
Table 5: S imulation Mode l Run R es ul ts For Midpoint Bridge 25.68 26.39 35.9 1 1 0 12 15 2 8 25.4 8 26.11 32.36 30.30 32. 1 0 59.05 27.21 29.05 52.28 24.12 24.40 25.69 23.20 23.49 24.49 23.93 23.96 2 4 .9 5 24.00 23.95 24.82 23.90 24.02 24.93 10 13 25 22.00 22.64 28.86 28.03 30.57 49.84 26.09 26. 80 41.87 15.24 15 .33 19.75 20.65 21.27 24.41 23.52 23 .81 24.99 23.38 23. 61 25.04 N/A N/A N/A 10 13 23 21.97 22.55 27.26 28.25 30,68 49.69 26.04 27.03 40.03 1 5.27 1 5 .20 10,42 19.70 20.70 22. 84 23.44 23 .44 23.89 22.61 22.92 23.42 23.41 23.2 0 23.70 II 13 23 22.68 23.07 27.42 30.54 31.74 44.90 30.76 31.5 5 42 .63 26.84 27.17 32.39 25.19 25.44 28.98 25.21 25.56 15 .62 15.83 17.09 N/A N/A N/A
Summary of Findings Simu btion results indicate that there are no significant reductions in either queue lengths or delays due to the presence of reversible lanes in all the three years for which simulation models have been developed on all three bridges. ETC participation rates assumed in the study (50% for Cape Coral and Midpoint, 60% for Sanibel bridges ) will be a critical factor to analyze traffic conditions at toll pla7..as. This particular ETC participation rate has been assumed to make the simulation modeling easily understandab le. However, because of the uncertainty over ET C participation rate, the results for current year may not represent the real situation accurately as it is possible that 50% of the tota l users will not be equipped electronic tags in th e current year. The results show that the queue lengths, transaction times, and delays increase slightly due to the presence of gates in the toll lanes. The queue lengths and transaction times hav e increased by about I 0-20% for models without reversible lanes and by about 3-8% for models with reversible lanes The results from models with dedicated ETC lane (Model #5), indicate that for the Cape Coral bridge, both queue length and delays will increase slightly. These overall increases are due to increased q ueues and delays for those vehicles using the ETC/ACM lanes (lanes 3 and 4) The vehicles, which use these lanes, are the ETC with coin drop and the ACM vehicles. However, the availability of ACMs in lanes I and 2 might alleviate the delays, as there is some spare capacity in these lanes. Once ETC is up and running and both a percentage of ETC users and ETC users with coin drop is better known, CUTR can refine this model. Until then CUTR recommends continuing to leave the option of a dedicated ETC lane on Cape Coral Bridge open.' Having a dedicated ETC lane on the Midpoint bridge produced good results as the increase in delay and queues was observed to be insignificant (3.2% in 1997 and 2% in 2001). It could be due to the availability of an extra lane (the Midpoint bridge has six l anes in each direction) for ETC coin drop vehicles and vehicles using exact change. Therefore, based on delay times and 11
queue l engths a l one, it is beneficia l to place a dedicated ETC lane on the Midpoint Bridge. For marketing purposes the existence of a dedica t ed ETC lane is extremely valuab l e and co u ld entice a significan t n umber of patrons to use ETC. The traffic conditio n s in the two future years mode l ed, 2001 and 2011, do not cause any s i gnificant increase in queues or del ays as long as the assumed 50% ETC partic i pation rate is maintained. The extremely high delays in model #5 for Cape Coral and Sanibel bridges is caused by increased traffic in future years and having the dedica ted ETC lane with 50% ETC patronage. I f the ETC patronage rises above 50% i n the future (year 2011) then thi s dedicated ETC l ane may be beneficial. Co ncl us i o n s a nd R eco m men d at i ons No reversible lanes are required for the current year and the two future years modeled, as they are not found t o cause any significant reductions in either the queue lengths or delays. CUTR re c ommends haviog a dedicated ETC l ane on the Midpoi n t Bridge, but further rese arch is necessary to determine the impacts of havi n g a dedicated ETC lane on Cape Coral Bridge, so that it does not result in any undue delays in the lanes used by ACMIETC with coin drop vehicles CUTR recommends not having a ded i cated ETC lane on the Sanibel Bridge. 12
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Burris, Mark Whitman,
Simulation modeling of toll plaza traffic at Midpoint, Cape Coral, and Sanibel bridges
h [electronic resource] /
prepared by Mark Burris, Ramakrishna Apparaju for the Lee County Variable Pricing Team.
i At head of title:
Task #1, second interim report
Task number 1, second interim report
b University of South Florida, Center for Urban Transportation Research,
1 online resource (12 leaves) :
"October 15, 1997."
"CUTR account no. 21-17-271-L.O."
Description based on print version record.
x Computer simulation.
Lee County (Fla.)
University of South Florida.
Center for Urban Transportation Research.
Burris, Mark Whitman, 1970-
t Simulation modeling of toll plaza traffic at Midpoint, Cape Coral, and Sanibel bridges.
Tampa : University of South Florida, Center for Urban Transportation Research, 
Center for Urban Transportation Research Publications [USF].
y USF ONLINE ACCESS