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Entrance Gate Issues The entrance gate queues at marine container terminals have long been identified as bottlenecks and sources of delay for port drayage. The process for entering a marine terminal is more complex than exiting, and queues are common for drivers seeking to enter. These entrance gate queues at marine container terminals serve as buffers between the marine terminal operation and the demands of customers. Time spent in the queue is unproductive, and idling in the queue is easily identifiable as a significant source of unnecessary emissions and noise. In slack periods, drivers often can drive directly to the gate itself, with no time in the queue. On the other extreme, drivers at some terminals frequently have reported queue times of 2 hours, with anecdotal reports of even longer waits. A driverâs decision to join a queue at any given moment (or the dispatcherâs decision to send the driver to the terminal) is a complex mixture of free choice and compulsion depending on the following: â¢ The dispatcher and driverâs experience-based estimate of how long will be spent in the queue. A significant number of drivers are not regular port visitors. â¢ The driverâs options for waiting, taking another assignment, stopping for a meal, quitting for the day, etc. Motor carriers balance the customerâs service requirements with ship schedules and ter- minal capacity limitations. â¢ The driverâs expected revenue under various options. â¢ The time remaining in the driverâs working day. It is critical to observe that motor carriers and drivers are rational, profit-motivated businesses. When they join a long queue, it is likely the optimal decision for that company and driver at that time, given the information available. Most drayage drivers are paid by the move, not by the mile or by the hour. If they already have a container that is headed to the port (e.g., they have picked up an export load or an empty from an import load), it is likely that it would be time consuming (and therefore costly) to exchange that unit for another assignment. Waiting until the queue goes down yields no revenue, and may reduce the number of moves the driver can make that day. With a very narrow range of revenue-generating alternatives, it is usually in the driverâs best interest to join the queue, even if it is a long one. Usually, there are no satisfactory data available on queuing times. Terminal information sys- tems do not capture queue times. Almost all the data available in the literature are from driver surveys. Since these are the products of driversâ memories, impressions, and estimates rather than actual measurements, these data are not usable in any kind of rigorous analysis. Researchers rarely have access to data on internal terminal activities when performing gate surveys, so the survey data are rarely linked to volumes, arrival distribution, transaction types, number of gates, type of gate, or other information that would facilitate an analysis of cause and effect. Most sur- veys ask for overall turn time, and do not separately identify gate queuing time. Moreover, given 47 C H A P T E R 6 Marine Terminal Gate Queuing
the number of factors that affect dray turn time, a simple average is of little use. A more accurate and insightful analysis requires identifying the variability in queue times and the reasons for that variability, which, in turn, requires a distribution rather than an average. Driver/Truck Arrivals The number of drivers and trucks arriving during a given time period varies with the volume of work to be done and the choices made by drivers, customers, and dispatchers. As long as vessel arrivals and departures and customer shipping and receiving practices result in peaking, it is prob- ably impossible to eliminate queuing congestion and delays completely. The arrivals at the gate vary by day of week. At one terminal, sample data show Friday to be the busiest (Figure 6â1). Other port and terminal data generally show heavier activity toward the begin- ning of the week, or show different distributions with more extreme peaking. These day-of-week variations should be predictable and accommodated. The pattern of arrivals over the week depends on vessel schedules and customer choices. Customers are notified when vessels arrive and their import containers are unloaded. They, in turn, notify the drayage driver and typically want the import boxes quickly, often on the same day as unloading. The rush to get newly unloaded import containers accounts for peak queues on vessel arrival days. Similarly, there is an export peak as ves- sel departure day approaches, and exporters work to get their outbound containers to the marine terminal before the vessel cutoff time. Figure 6â2 shows hourly arrival patterns at Bayport, Port of Houston, for July 2009. The peak days were Tuesdays, with the peak hours being in the middle of the morning. Consistent daily peaking is also typically observed. It is common to observe long queues before the gates open in the morning and during lunch and coffee breaks. Since both drayage firms and their drivers are usually paid by the move, they have an incentive to make as many moves as pos- sible as soon as possible. A driver who starts early has a better opportunity to make more moves and earn more revenue than a driver who is less aggressive. Long-distance drivers arriving in the port area in the middle of the night often prefer to wait overnight in the marine terminal queue area so they can continue their trip as early as possible the next day. 48 Truck Drayage Productivity Guide Figure 6â1. Day-of-week gate arrivalsâsample terminal data. Sample 2007 Day of Week Entrance Gate Distribution 0 20,000 40,000 60,000 80,000 100,000 120,000 Monday Tuesday Wednesday Thursday Friday A nn ua l I nb ou nd M ov es
Cargo flows and transaction volumes at most marine terminals are inherently uneven. On ves- sel arrival days, a surge of import boxes passes from the vessel into the terminal. Import customers typically want their goods quickly, so there is a surge of drayage activity as well. Exports tend to arrive at the terminal during the week prior to vessel arrival, peaking before the outbound book- ing cutoff. Once the vessel is gone, activity declines. Marine terminal gate hours vary, but most are roughly 8 A.M. to 5 P.M. Some terminals close the gates during lunch breaks, some keep them open. Customer hours also vary, but are commonly 8 to 5. Customers tend to prefer receiving imports in the morning and shipping exports in the afternoon. Although marine terminal gate hours and container shipping and receiving hours may seem to align, in practice they often do not because of the time and distance between them. A drayage driver first in line at 7 A.M. can expect to leave the marine terminal with an export load by about 7:30 A.M. If the customer is 2 hours away, delivery will not be until 9:30 A.M. On the export side, a shipper 2 hours away must ship by 1:30 P.M. to be reasonably sure of getting the container in the gate by 4 P.M. For that shipper to receive at 8 A.M. and ship at 5 P.M., the marine terminal would have to be open from 5:30 A.M. to 7:30 P.M. Since both drayage firms and their drivers are usually paid by the move, they have an incentive to make as many moves as possible. A driver who can start his first move at 8 A.M. by being in line at 7 A.M. has an opportunity to make more moves and earn more revenue than a driver who waits for the congestion to clear and starts his first move at 10 A.M. The second driver has a faster turn time on his first trip, but the first driver may earn more by making more trips in the day. Although many distribution centers (DCs) operate beyond the standard business day, most cargo is still shipped between 8 A.M. and 5 P.M. Gate Queuing Solutions The Gate Queuing Dilemma For all the reasons above, gate queuing is difficult to reduce, much less eliminate. In California, legislation forced San Pedro Bay terminals to adopt appointment systems and develop PierPASS (described later) to avoid being subject to massive fines for long queues. As of Marine Terminal Gate Queuing 49 Figure 6â2. Arrival patterns at Bayport, Port of Houston.
2010, however, trade growth and cost-based reductions in gate hours have led to massive queues when San Pedro Bay terminals change from fee-based to free entry each evening at 6 P.M. The uneven pace of truck arrival and existing labor rules presents terminal operators with a dilemma: to keep gates fluid and truck queues short, the terminal operators would have to hire sub- stantially more labor than is actually required to handle the trucks. In an industry characterized by relentless cost pressure, the decision will often favor the terminal operatorâs budget at the expense of the drayage drivers. Appointment Systems Appointment systems are largely confined to Southern California at present. They have a mixed record there but hold the potential for wider application and are of interest to other ports and oper- ators. Appointment systems have the following twin purpose: â¢ To allow drayage firms to make efficient dispatching plans with reduced driver queue times and â¢ To let marine terminals control workloads, thereby reducing drayage congestion and delay. Several Southern California appointment systems were tried in response to threats of legislation over driver queue times. Some have fallen into disuse, but the remaining systems have been improved and refined. Maersk has subsequently adopted an appointment system at its new termi- nals in Virginia and Mobile, Alabama. That system, however, presently uses 4-hour appointment windows and serves primarily as a planning tool for the terminal operators. Because a driver can sometimes make multiple trips in a 4-hour window, there have been occasions when it was not clear which appointment the driver was keeping. Most appointment systems have been designed with little input from drayage firms or drivers. There are a number of issues that have yet to be resolved in a uniform system, including the following: â¢ How available appointment windows will be allocated, â¢ How the gate will differentiate between drivers with and without appointments, â¢ How drivers without appointments will be handled, â¢ What obligations the terminal has to a driver who makes and keeps an appointment, â¢ What obligations a driver has to a terminal if he breaks an appointment, and â¢ Whether the appointment system will be used throughout the port. The variability of over-the-road and urban transit times, discussed at length in Chapter 9, places a limit on the precision of appointment systems. At one extreme, 4-hour windows do not struc- ture or regulate the flow of trucks. At the other extreme, 15-minute windows could not be main- tained in ordinary operations due to the inherent variability of both drayage and terminal operations. The tight delivery windows characteristic of just-in-time replenishment systems are kept by letting trucks idle nearby until the delivery window opens, which would defeat the pur- pose in the marine terminal environment. PierPASS Southern California ports generate large volumes of truck traffic that contribute to congestion and emissions in the Los Angeles basin. To ease the burden of international cargo delivered locally on local highways and to further improve air quality, the PierPASS system was instituted. The goal of PierPASS has been to encourage the movement of containers in off-peak hours. Since July 2005, all marine terminals in the Ports of Los Angeles and Long Beach have offered OffPeak shifts on nights and weekends. A Traffic Mitigation Fee of $50 per 20-ft equivalent unit (TEU), or $100 per 40-ft container, is assessed on containers drayed through the ports during peak daytime hours, with 50 Truck Drayage Productivity Guide
certain exceptions. At present, between 35%â40% of all cargo moving through the ports is mov- ing under the OffPeak Program. The traffic mitigation fee funds the extra labor for the OffPeak gate shifts. PierPASS fees are implemented through RFID tags and alternative forms of driver and company identification. For drayage companies that routinely do business at the ports, the system functions smoothly, operating in the background and not causing exceptions at the gates. For occasional users, the system can cause delays and disputes. Because PierPASS fees are not assessed after 6 P.M., drayage drivers wait outside terminal gates until that time. On busy days, this situation results in congested gates at, and shortly after, 6 P.M. The OffPeak fee is charged to the customer, not the trucker, so it is presumably the customer who has required the driver to queue up at 6 P.M. rather than enter the gate and pay the fee. Drayage firms and drivers are not ordinarily compensated more for waiting, so the driver has implicitly accepted a delay so the customer can save money. On the other hand, the PierPASS Program is predicated in part on the assumption that early morning and night hours will be less congested, so the driver may be accepting a gate queue delay but achieving a quicker overall turn time. By wait- ing in the queue at 6 P.M., he may be getting his work done earlier than if he waited until 7 P.M. or 8 P.M. when the queue had lessened. Reduced business volumes during the current recession have created problems for the Pier- PASS/OffPeak system. Fees paid for daytime entry are used to offset the cost of keeping gates open for extended hours. At present (2010), however, off-peak fee collection has reportedly declined and cost-conscious terminal operators would like to avoid the added cost of extended gates. At the same time, problems with daytime congestion have abated, reducing the need for nighttime capacity. Terminal operators have reduced staffing for both day and night operations, and truckers are reporting longer turn times even in the era of reduced trade. The longer turn times are particularly troublesome for truckers who have invested in new or retrofitted clean trucks, and who need enough daily turns to cover the truck payments. Most firms have structured their operations to take advantage of the nighttime hours, and now find those hours less productive. The PierPASS/OffPeak system was designed to mitigate the effects of growing daytime conges- tion at the Ports of Los Angeles and Long Beach. Despite imperfections and teething problems it was largely successful and both truckers and customers adapted operations to suit. Under chang- ing circumstances, the PierPASS/OffPeak Program will probably require more flexibility but the precise nature of that flexibility is not yet apparent. Advanced Terminal Gate Designs The most technically advanced gate observed by the NCFRP Project 14 study team was at APM Portsmouth, Virginia (Figure 6â3). The goal of the gate operation is to identify motor carriers with âcleanâ transactions early and process them quickly. There is an appointment system with a 4-hour window. Truckers tell the terminal when they are comingâmostly the day before. The trucks that have appointments equal 70%. Only 3% get trouble tickets. The average turn time is less than an hour. Each truck coming to the terminal must be equipped with an RFID tag or it is not permitted to enter. The RFID readers are located on the Western Freeway interchange. As the trucks pass the reader, a computer is activated and the terminal prepares for the truckâs arrival. The first step in the process is a seal check, which is done for all trucks entering. This task is done by a clerk in a pickup before arriving at the first building. The data are entered into a handheld Marine Terminal Gate Queuing 51
device, if necessary. The truck then proceeds to the first small building where a physical inspection is done by camera while the truck moves through. During the truckerâs transition to the next sta- tion, an inspector located in the headquarters building reads the inspection photos. About a third of the way to the next building there is an overhead message sign that tells the trucker which of three sets of lanes he should use. (One set of lanes is for trucks with no problems, another set is for trucks without appointments and those with trouble tickets, and another returns rejected trucks to the beginning.) At the second building, the driver swipes the TWIC. If the driver has an appointment and all is in order, the driver receives an entry permit and instructions. If the driver has an empty, the driver must get out and open the back door for an inspection by camera. This is a 2-minute process, on average. If the driver does not have an appointment, a more conventional process is conducted in the lower part of the second building. It takes 6 minutes, on average, a very typical process time. If there is any kind of trouble, the driver deals with the problem at the trouble buildingâa small building located between the in/out gates. The parking area is the most visible aspect of Figure 6â3. At times a queue develops between the first and second inbound buildings. The process is repeated at the out-gate with the radiation monitor being an additional step at the very end. 52 Truck Drayage Productivity Guide Figure 6â3. APM Portsmouth gate. Western Freeway RFID Readers on ramp and under bridge Seal Check and Equipment Inspection Cameras Problem Resolution Building Out Gate Facilities Administrative and Inspection Staff TWIC Check and Gate Pass Variable Message Sign