1 2 Transportation systems and their components play a substantial role in the U.S. and the world 3 economy . This research study serves as a guide to increase furt her research or perhaps to 4 continue improving the traffic system in this growing economy. The setting for this research 5 study is an oil spill incident on the Mississippi River near the Port of New Orleans (NOLA). Due 6 to several oil spills in the past, port efficiency is stunted due to delays in the movement of cargo 7 on the roads. The objective of this research study i s to develop a quick and efficient solution by 8 using the micro scopic simulation platform VISSIM to New Orleans Port operations from being 9 shut down due t o an oil spill scenario . The benefits were quantified based on total travel time and 10 total delay along the study corridor. Next, literature on past port oil spills and contingency plans 11 due to oil spills were further researched, as a part of the study to s erve as a guide to design the 12 near-perfect plan for execution. The present challenges with the port operations could be 13 alleviated through signal retiming during an oil spill incident. The after study results show the 14 heavy vehicles reduce the delay time . In addition, it also reduce heavy vehicles travel time , 15 provide s better heavy vehicles efficiency, and increase overall road network efficiency . 16 17 18 KEYWORDS 19 20 Oil Spill, Heavy Vehicle Traffic, Signal Retiming, Micro scopic Simulation , Travel & Delay 21 Time 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 3 BACKGROUND 1 2 Ports are best known for intermodal activity, connecting rail lines, truck lines, barge lines, cruise 3 lines, and ocean carriers. In terms of resilience, the management of port activities is significant 4 on both local and national lev el. T he setting for this research study i s an oil spill on the 5 Mississippi River near the Port of New Orleans , Louisiana . The ob jective of this research study 6 is to develo p a quick and efficient plan for the operation of Port of New Orleans (NOLA) from 7 being shut down due to an oil spill scenario. Microsimulation platform VISSIM is coded to 8 develop a quick and efficient plan. VISSIM is a microscopic multi -modal traffic flow simulation 9 software package developed by PTV (1–3). Oil spill in this port generally occurs in the ocean 10 waters itself, however, due to the speed of the flow of ocean water, it would mo ve it further 11 upstream. By shutting down the port, return of port operations would ta ke between few hours up 12 to several days in range. This would in turn cause negative effects on the port operations and 13 local economy . 14 15 Due to oil spills in the past, numer ous plans have been devised to return to operations 16 from shutdown, efficiently and effectively. In 2010, deep water horizon oil spill showed marked 17 impacts on Gulf Coast residents as commercial ties to renewable resources were heavily 18 damaged (4). An idea to devise an efficient plan, the recognition of human dimensions of spills 19 and response is crucial to properly construct a plan of action (5). Exercises in plan execution and 20 conclusions of effectiveness are currently run to properly re -engage in daily act ivities after 21 facing an oil spill. Most often, traffic software by simulating controls and routes were used, help 22 aid in the resumption of port operations. 23 24 Various journals are reviewed and described about the past oil spills that occurred in, or 25 near the vicinity of the Port of New Orleans. Numerous gathered information proved useful in 26 gaining relevant and critical information on how the shutdown of port operations c ould have 27 been prevented, determining the best ways to mitigate an oil spill, and getting the port back to 28 work and running in the most expeditious and efficient manner possible. 29 30 The Liberian tanker, Westchester, ran aground in the Mississippi River, spilling a half - 31 million gallons of crude oil, effectively closing 26 miles of one of the busi est shipping routes in 32 the United States of America (6). It was noted that, due to the tanker’s Liberian ownership and 33 Bahamian registration, the tanker was an antiquated carrier that possessed only one hull, unlike 34 modern American tankers which are built with two hulls to prevent such spills in circumstances 35 such as this. Federal law dictated that all tankers operating in U.S. waters must be double hulled 36 by 2015, which the Westchester was scheduled to do in 2006 (6). It was unclear what exactly 37 caused t he tank to rupture, though it was speculated that the carrier could have hit something 38 already on the river bottom or that its very own anchor could have become pinned between the 39 hull and the river bottom causing the puncture in the hull. Unfortunately, due to the nearby 40 wetland’s drought -stricken conditions, several cuts had been made to divert river water into the 41 parched areas, potentially exposing various wildlife species to hundreds of thousands of gallons 42 of oil. Containment booms were set out, acco rdingly, to prevent such a disaster. Two days after 43 the spill occurred, the coast guard expected the closed route to be reopened for business, as 44 usual. 45 4 Oil spill in 2005 showed devastating effects of hurricane Katrina w ere undeniable . One 1 of the most under -reported disasters resulting from the Category 4 hurricane where 46 destroyed 2 and 20 damaged oil platforms occurred in the Gulf of Mexico (7). Approximately, 50 oil spills 3 were reported in the Louisiana and Mississippi shoreline areas, with Murphy O il responsible for 4 the largest release of oil at approximately 819,000 gallons due to an above -ground storage tank 5 becoming dislodged because of storm surge and flooding that was associated with Hurricane 6 Katrina (7). The oil was spilled into a densely -populated area of St. Bernard Parish and impacted 7 roughly 1,700 homes and local canals (7). While all the spills were because of Hurricane Katrina, 8 the cleanup efforts were significantly different for each event due to the location of the spills, 9 residentia l versus marsh areas, and accessibility complications. The in situ burn technique 10 proved to be the most effective method for the reduction of impact on the sensitive coastal marsh 11 areas (7). 12 13 A 61-foot barge carrying 419,000 gallons of heavy fuel collid ed with a 600 feet tanker 14 ship early morning on July 23rd, 2008 (8). The leaking fuel went undetected for two days thus 15 polluting the Mississippi River (8). It was noted that the smell of the fuel was so pungent that it 16 could be smelled from miles, which d etoured tourists from visiting the famous New Orleans 17 French Quarters or walking along the boardwalk. Tens of thousands of feet of plastic booms 18 were deployed to keep the fuel from reaching secondary passes. These plastic booms were also 19 placed around the Delta National Wildlife Refuge, located at the mouth of the Mississippi River 20 (8). Skimmer boats were used to extract the oil from the top of the water, while most of the oil 21 would be pushed out to the Gulf of Mexico due to the fast -moving waters (8). Duri ng the time of 22 the cleanup efforts, the Mississippi River was closed to all boat traffic, which consisted of nearly 23 200 vessels (8). After two days of extensive cleanup, the Coast Guard opened the river for 24 limited use. It was estimated that the city’s por ts lost a minimum of $100,000 USD per day while 25 the river was closed (8). Coast Guard officials also noted that the towboat operator that was 26 responsible for the barge was not licensed for this line of work. 27 28 An explosion on the Deepwater Horizon oil rig c aused history's largest marine oil spill 29 (9). The explosion was caused by a surge of natural gas which cracked the recently installed 30 concrete core (9). It was later found that, due to the concrete's curing process, the new core was 31 too weak to withstand t he level of pressure to which it was exposed. The ascending natural gas 32 then made its way to the platform, where it ignited and killed 11 workers (9). With the rig now 33 detached from the ocean floor, oil was flowing freely without any opposing forces stoppi ng it. In 34 addition, oil volumes of 60,000 barrels per day were leaking, contamination efforts were of high 35 urgency (9). Apparatus called as Marine Riser Package Cap was soon placed over the leaking oil 36 to siphon it to a nearby tanker . The apparatus , as mentioned above, was only a temporary 37 solution as it was not a perfect fit and oil was still being released into the Gulf of Mexico. A 38 more perman ent seal was placed , but by that time an estimated 4,900,000 barrels of oil had 39 already been released int o the Gulf . Due to the enormous size of the leak, several styles of 40 cleanup measures were taken. Approximately 1.8 million gallons of dispersants were placed in 41 the oil -filled water as means for bacteria to metabolize the oil . Booms were placed at strategic 42 points to corral the oil, after which it siphoned or burned. Manual removal of the oil was required 43 for all beaches affected throughout the gulf. It is estimated that 1,100 miles of shoreline were 44 polluted (9). The impacts of the spill are irreve rsible as its impact affected marine life and the 45 fishing industries to levels beyond measure. Proper action plan by using a microsimulation 46 5 platform and taking the right guidelines to get the port back to operation during an oil spill are 1 the gaps in the literature on this topic. Therefore, the ob jective of this research study wa s to 2 develop a quick and efficient solution by using microsimulation platform to New Orleans Port 3 operations from being shut down due to an oil spill scenario . 4 5 METHODOLOGY 6 7 The aim of this research study is to develop a quick and efficient plan of action by using 8 microsimulation platform to get the port back in operation during an oil spill incident. This 9 avoid s delays to the movement of cargo on the roads and within the port . By u sing micro - 10 simulation platform VISSIM, an action plan is designed to bring Port of New Orleans back to 11 normal operating condition during an oil spill incident . VISSIM version 9.0 micro -simulation 12 platform i s selected to build the model, as this software is one of the most widely used 13 microscopic simulation packages for traffic engineering studies worldwide. 14 15 Port Operation Plan during an Oil Spill Incident 16 17 Port of New Orleans consists of three parts: Uptown terminal, downtown terminal and 18 inner harbor terminal . Normally all goods are delivered at the uptown terminal. However, i n case 19 of an oil spill incident the downtown terminal is chosen for deliver ies of containership and barge 20 goods. The Uptown Terminal in port NOLA is the main terminal for loading and unloading of 21 cargo goods , moreover, all cargo storage facilities are located in this terminal area . 22 23 24 Figure 1. Port of New Orleans 25 26 The contingency plan for the oil spill incident w ould move the containership and barge 27 deliveri es intended for the Uptown Terminal to be directed to the Downto wn Terminal . All the 28 oil spill incidents occur in or near the vicinity of the Uptown Terminal facilities. Redirecting of 29 marine traffic from the Downtown Terminal to the Uptown Terminal would increase the number 30 6 of deliveries and heavy vehicles/truck traffic , as all t he cargo storage facilities are located in the 1 Uptown Terminal . 2 3 During an oil spill incident, the heavy vehicles/truck traffic increase traffic congestion 4 near the port Uptown a nd Downtown terminal . Subsequently, due to the traffic congestio n the 5 total travel time and delay increase , in addition , the average speed decrease of the heavy vehicle. 6 This cause an overall delay of the port operations due an oil spill situation. Therefo re, a micro 7 simulation VISSIM model is built to replicate the exact traffic situation of the field, and signal 8 retiming was performed and before and after analysis is conducted. 5 signalization intersection 9 was selected for this research study. The researc h study is comprised of total 2.1 miles , near the 10 Uptown terminal . Tchoupitoulas St. & Henderson St. is the east border and Tchoupitoulas St. & 11 Louisiana Ave is the west border of the study corridor. The analysis was conducted for both 12 eastbound and westbo und directions of travel and for morning peak period from 7 AM - 9 AM. 13 The list of the intersection of the selected corridor near the uptown terminal for the simulation 14 model a re listed in the following table: 15 16 Table 1. List of Int ersection of the Study Area in Uptown Terminal , Port of New Orleans, Louisiana 17 18 No. Signalized Intersections 1. Tchoupitoulas St. & Henderson St. 2. Tchoupitoulas St. & Felicity St. 3. Tchoupitoulas St. & St Mary St. 4. Tchoupitoulas St. & Jackson Ave . 5. Tchoupitoulas St. & Louisiana Ave. 19 Signalized Intersection Design 20 21 Designing of signalized intersection was performed by using micr o simulation platform VISSIM 22 version 9.0. In order to design a si gnalized intersection in VISSIM 9.0, various traffi c data was 23 required. Various field data for building the microsimulation model was collected from 24 Louisiana Department of T ransportation & Development, Port of New Orleans Authorities and 25 from traffic counters from Louisiana Geocounts such as: 26 • Geometric d ata: length of lanes, number of lanes, lane location, and lane assignment. 27 • Signal timing plan: number of phases, cycle lengths, duration of phases for different time of 28 the day 29 • Heavy vehicles/ Truck travel time, delay time, dwell times and distribution of dwell times 30 • Volume data , speed data, turning movement counts 31 32 Geometric data were obtained from aerial images ; information on heavy vehicle operation was 33 obtained from Port of New Orleans authorities, traffic data and signal timing plans were obtained 34 from traffic counters in Louisiana Geocounts . The port directory provided up to date information 35 on the average daily truck cargo deliveries, annual break -bulk cargo tonnage, and annual 36 containers received. On a normal day about 2130 truck drivers haul cargo in and out of the Port. 37 7 1 Measures of Effectiveness (MOE): The MOE’s for evaluating the impacts o f signal retiming 2 and performing before and after analysis are travel time, total travel time, delay time and total 3 delay time . Total delay measures the differe nce between free flow travel time and actual travel 4 time including control delay . Total delay also measures the time the truck was below the desired 5 velocity for a signalized inter section approach. The MOEs used here are consistent with the 6 reviewed studie s and provide s a good r epresentation of the signal retimin g impact to truck 7 operations. 8 9 Truck Travel Time: Truck travel time is an aggregate measur ement of travel times on all truck 10 route included in the analysis. Therefore, this measure will inclu de ben efits received by truck 11 movements and losses received by others arriving near the transition to or from a signal retiming. 12 Therefore, this MOE will provide a good representation of the performance of the entire sys tem 13 and the applied signal retiming . 14 15 Truck Delay Time: Truck delay is reflected in the truck travel time, but it is also a measurement 16 of the e ffectiveness of the signal retiming since it specifically examines delay due to traffic 17 signal ope rations. A large decrease in truck delay equates to an increased green time by the 18 traffic signal controller. 19 20 Strategy used for Signal R etiming 21 22 As a ll 5 intersection are fully actuated. Green extension strategy is used to extend the 23 green interval by up to a pr eset maximum value if a heavy vehicle is app roaching. Detectors are 24 located so that any heavy vehicle that would just fail to catch the green light ("just" meaning by 25 no more than the specified maximum green extension time) extends the green and is able to clear 26 the intersection rather than waiting through an entire red interval. Green Extension provides a 27 benefit to a relatively small percentage of trucks (only trucks that arrive during a short window 28 each cycle benefit), but the re duction in delay for those trucks that do benefit is large (an entir e 29 red interval). For the west and east bound approach the maximum green time was increased by 30 30 seconds for all five intersection. 31 32 Table 2. Maximum Green Before and After Study 33 No. Signalized Intersections Max. Green Interval Before Study Max. Green Interval After Study 1. Tchoupitoulas St. & Henderson St. 60 90 2. Tchoupitoulas St. & Felicity St. 60 90 3. Tchoupitoulas St. & St Mary St. 40 70 4. Tchoupitoulas St. & Jackson Ave. 40 70 5. Tchoupitoulas St. & Louisian a Ave. 50 80 8 1 Therefore, successful port operations have to be insured in the event of an oil spill. As 2 ports are best known for their intermodal activity, connecting rail lines, truck lines, barge lines, 3 cruise lines, and ocean carriers. Therefore, a pla n of execution was documented that fits during 4 an oil spill incident . The following figure shows the steps to be taken in case of an oil spill 5 incident at Port of New Orleans. 6 7 The steps taken during an oil spill incident are in the following figure. This research 8 project only focusses on the signal retiming part. 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 9 1 2 FIGURE 1 Steps Taken during an Oil Spill Incident at port NOL A 3 10 RESULTS & DISCUSSION 1 2 This section evaluates the before and after analysis results through implemen tation of 3 Signal Retiming . Achieved benefits are described by using different MOEs and their evaluation 4 before and aft er the implementation of signal retiming for the study co rridor. MOEs used in this 5 project for evaluation are tot al travel time, travel ti me, delay tim e and total delay time for all 6 vehicles and for truck only. MOE compari son for both before and after signal retiming scenarios 7 are presented by tables and graphs. 8 9 Evaluatio n of effectiveness of Signal Retiming applied on Tchoupitoulas St. Corridor, 10 Port of New Orleans from Louisiana Ave (West Border) and Henderson St. (East Border) is 11 presented in this section . For easy understanding, results are presented for both directions. In this 12 evaluation of effe ctiveness of Signal Retiming , travel ti me and delay between the intersections 13 were considered . Next, results are presented for all vehicles in th e system, as well as, for truck 14 only. 15 Table 3. All Vehicles Travel Time Comparison 16 Travel Time (Seconds) - All Vehicles Westb ound Eastbound Segment Before Signal Retiming After Signal Retiming Segment Before Signal Retiming After Signal Retiming Tchoupitoulas St. & Henderson St. 67.57 64.68 Tchoupitoulas St. & Henderson St. 63.34 47.89 Tchoupitoulas St. & Felicity St. 69.89 55.35 Tchoupitoulas St. & Felicity St. 40.67 32.67 Tchoupitoulas St. & St Mary St. 44.4 40.73 Tchoupitoulas St. & St Mary St. 29.4 25.07 Tchoupitoulas St. & Jackson Ave. 30.72 25.39 Tchoupitoulas St. & Jackson Ave. 55.31 47.08 Tchoupitoulas St. & Louis iana Ave. 104.63 99.32 Tchoupitoulas St. & Louisiana Ave. 101.91 95.77 Total Travel Time 317.21 285.47 290.63 248.41 17 The total travel time is estimated separately for westbound and eastbound directions, and 18 for all vehicles and truck only separately. T able 3 and Figure 2 provides all vehicles travel times 19 along the study corridors before and after signal retiming. 20 21 • Overall, after signal retiming simulation model results are better than the before signal 22 retiming, in addition, the total travel time resu lts of truck only are lower after signal 23 retiming. 24 11 • Moreover, the simulation results of the travel time for east and west bound direction are 1 also similar for both all vehicles and truck only. It was also noticed that the travel time 2 for each segment in the model are different for each direction. 3 • Furthermore, simulation results of total travel time of all vehicles are considerably lower 4 in the model compared to the total travel time of truck only. 5 6 In the tables presented below (Table 4 & Figure 2 ) provides for travel time s truck only in 7 the system. Moreover, c omparison for all vehi cles and truck only showed that travel time was 8 less at all intersections for the model after signal retiming . It indicated that the highest benefits 9 achieved through implementati on of signal retiming occurred on segments between 10 Tchoupitoulas St. and Felicity St. for west bound, and Tchoupitoulas St. and Henderson St. for 11 east bound. 12 13 Table 4. Truck Only Travel Time Comparison 14 Travel Time (Seconds) - Truck Only Westbound Eastbound Segment Before Signal Retiming After Signal Retiming Segment Before Signal Retiming After Signal Retiming Tchoupitoulas St. & Henderson St 129.50 117.40 Tchoupitoulas St. & Henderson St 116.03 110.99 Tchoupitoulas St. & Felicity St. 85.80 63.77 Tchoupitoulas St. & Felicity St. 76.18 68.05 Tchoupitoulas St. & St Mary St. 55.42 42.65 Tchoupitoulas St. & St Mary St. 60.73 58.21 Tchoupitoulas St. & Jackson Ave. 85.62 82.53 Tchoupitoulas St. & St Mary St. 65.63 60.57 Tchoupitou las St. & Louisiana Ave. 172.92 152.30 Tchoupitoulas St. & St Mary St. 155.89 143.53 Total Travel Time 529.26 458.65 474.46 441.35 15 Total travel time f or all vehicles with Before Signal Retiming was 317.21 seconds for 16 the west bound, 290.63 seconds for the east bound, and, total travel time for all vehicles with 17 After Signal Retiming was 285.47 seconds for the west bound, and 248.41 seconds for the east 18 bound. 19 20 12 1 2 FIGURE 2 All Vehicles and Bus Only Travel Time Comparison for Both Direction 3 13 Moreover, the total travel time for truck only Before Signal Retiming was 529.26 1 second s for the west bound, and 474.46 seconds for the east bound, and, total travel time for 2 truck only After Signal Retiming was 458.65 seconds for the west bound, and 441.3 5 seconds for 3 the east bound. The travel time results of After Signal Retiming for all vehic les and truck only 4 for both direction showed enough benefits to be implemented in the area. 5 6 Delay time measured the excess time consumed in traversing the intersec tion. Moreover, 7 delay time MOE is complex due to random arrival of vehicles, lost time due to stopping of 8 vehicles, over saturated flow conditions etc. Next, the results were presented for the MOE Delay 9 for all vehicles in th e system, as well as, for truck s only for both east and west bound direction. 10 As for the Tchoupitoulas St. Network, the (Table 5 & Figure 3 ) provided detailed comparison of 11 the delay time for both direction for all vehicles . 12 13 • Overall, after signal retiming model simulation results are better than the before signal 14 retiming model, in addition, the total delay time results are lower after signal retiming. 15 • Moreover, the simulation results of the delay time for east and west bound direction are 16 also similar for both all vehicles and truck only. It was also noticed that the delay time for 17 each intersection in the model are different for each direction. 18 19 Table 5. All Vehicles Delay Time Comparison 20 Intersection Delay Time (Seconds) - All Vehicles Westbound Eastbound Before Signal Retiming After Signal Retiming Before Signal Retiming After Signal Retiming Tchoupitoulas St. & Henderson St 22.90 17.13 16.19 15.18 Tchoupitoulas St. & Felicity St. 38.56 33.16 38.94 35.20 Tchoupitoulas St. & St Mary St. 20.32 16.37 11.35 8.26 Tchoupitoulas St. & Jackson Ave. 16.45 11.57 14.53 11.46 Tchoupitoulas St. & Louisiana Ave. 48.84 39.91 34.78 30.01 Total Delay Time 147.07 118.14 115.79 100.11 21 In the tables presented below (Table 6 & Figure 3) delay times between th e intersections 22 truck only in the system. Moreover, c omparison for all vehi cles and truck only showed that delay 23 time was less at all intersections for the model after signal retiming. It indicated that the highest 24 benefits achieved through implementation of signal retiming for all vehicles occurred on 25 intersection between Tchoupitoulas St. and Louisiana Ave. for both directions . Also, for truck 26 only the highest benefit occurred on intersection between Tchoupitoulas St. and Louisiana Ave. 27 for both direction. 28 14 1 Table 6. Truck Only Delay Time Comparison 2 Intersection Delay Time (Seconds) - Truck Only Westbound Eastbound Before Signal Retiming After Signal Retiming Before Signal Retiming After Signal Retiming Tchoupitoulas St. & Hender son St 19.70 11.65 23.62 20.36 Tchoupitoulas St. & Felicity St. 39.02 31.22 15.45 12.11 Tchoupitoulas St. & St Mary St. 23.42 15.21 20.26 17.13 Tchoupitoulas St. & Jackson Ave. 21.98 17.03 14.91 11.51 Tchoupitoulas St. & Louisiana Ave. 42.98 27.88 38.50 30.5 Total Delay Time 147.10 102.99 112.74 91.61 3 Total delay time f or all vehicles with Before Signal Retiming was 147.07 seconds for the 4 west bound, 115.79 seconds for the east bound, and, total delay time for all vehicles with After 5 Signal Retimin g was 118.14 seconds for the west bound, and 100.11 seconds for the east bound. 6 7 8 9 10 11 12 13 14 15 16 17 18 19 15 1 2 3 4 FIGURE 3 All Vehicles and Bus Only Delay Time Comparison for Both Direction 5 16 1 Moreover , the total delay time for truck only Before Signal Retiming was 1 47.10 second s 2 for the west bound, and 112.74 seconds for the east bound, and, total delay time for truck only 3 After Signal Retiming was 102.99 seconds for the west bound, and 91.61 seconds for the east 4 bound. The travel time results of After Signal Retimin g for all vehic les and truck only for both 5 direction showed enough benefits to be implemented in the area. 6 7 Statistical Analysis 8 9 As the sample size of this research study is below 30, a t-paired test at 95% confidence 10 interval was performed to check the n ull hypothesis that travel time for the before and after travel 11 time for all vehicles and truck only are equal . For all vehicles, the t critical two -tail value was 12 2.262 and the t statistics value was 4.7452. For truck only, the t critical two -tail value w as 2.262 13 and the t statistics value was 5.4904. Therefore, for both all vehicles and truck only rejected the 14 null hypothesis, therefo re, the signal retiming values are significantly different. 15 16 CONCLUSION S 17 18 The present challenges with the port operations c ould be alleviated through signal 19 retiming during an oil spill incident. The after study results shows the heavy vehicles reduce 20 delay time . In addition, it also reduce heavy vehicles travel time , provide better heavy vehicles 21 efficiency, and increase overall road network efficiency . 22 23 The objective of this research was t he ob jective of this research study wa s to develop a 24 quick and efficient solution by using microsimulation platform to New Orleans Port operations 25 from being shut down due to an oil spill sc enario . The benefits were quantified based on total 26 travel time and total delay along the study corridor. The study corridor was a 2.1 -mile section on 27 Tchoupitoulas St., Port of New Orleans, Louisiana. A microsimulation models were developed in 28 VISSIM: (a) a base model without signal retiming; and (b) an advanced model with signal 29 retiming. Table 7 compares the performance of the se two simulation models . The after-signal 30 timing study was found to improve the performance of heavy vehicles, moreover, it great ly 31 reduced the travel times and the total delay times for heavy vehicles and all vehicles. 32 33 Table 7. Comparison of Before and After Study of the Performance Measures 34 Total Travel Time (Sec) Vehicle Type Direction Before Signal Retiming Model After Signal Retiming Model ALL Vehicles West Bound 317.21 285.47 ALL Vehicles East Bound 290.63 248.41 TRUCK Only West Bound 529.26 458.65 TRUCK Only East Bound 474.46 441.35 Total Delay Time (Sec) ALL Vehicles West Bound 147.07 118.1 4 ALL Vehicles East Bound 115.79 100.11 TRUCK Only West Bound 147.10 102.99 TRUCK Only East Bound 112.74 91.61 35 Based on the simulation results, it can be concluded that after signal retiming the heavy 36 vehicle system operations is effective and reli able. The effectiveness of this method also helps to 37 17 cut fuel cost, less environmental pollution and eventually provide better operation of the port 1 from being shut down due to an oil spill incident. 2 3