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CHAPTER 6 Marine Terminal Gate Queuing 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 driver's decision to join a queue at any given moment (or the dispatcher's decision to send the driver to the terminal) is a complex mixture of free choice and compulsion depending on the following: The dispatcher and driver's experience-based estimate of how long will be spent in the queue. A significant number of drivers are not regular port visitors. The driver's options for waiting, taking another assignment, stopping for a meal, quitting for the day, etc. Motor carriers balance the customer's service requirements with ship schedules and ter- minal capacity limitations. The driver's expected revenue under various options. The time remaining in the driver's 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 driver's 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 drivers' 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