Reducing Truck Emissions in Import Operations at Container Terminal—A Case Study in a Singaporean Port - Technology Management for Sustainable Production and Logistics - page 132

time of that truck and subsequent trucks already queued because of unnecessary
container movements. On the other hand, at the export yard, the export container
should be stacked following the stowage plan and it also takes time to move con-
tainers if the arrival pattern does not match the plan.
The waiting time of trucks can be shortened if the truck arrival pattern is matched
with the stacking plans for import and export containers. However, with the cur-
rent operation of TAS, it is very hard for the container terminal manager to keep the
arrival pattern under control. The approach proposed in this study is that the TAS
will offer available periods of time for pick-up of containers for each shipping com-
pany. Different shipping companies will have different available periods based on
the plans for stacking containers. It is a challenge to identify the optimal arrival pat-
terns via TAS. This optimization will minimize the emissions of idle truck engine
with the consideration of the inconvenience onto the shipping company which may
have due to the limited number of periods for pick-up of containers.
This study will propose a methodology for minimizing idle engine emission by
controlling arrival pattern via TAS. First, a mathematical model is formulated to
find the appropriate periods for delivery or pick up of containers for each shipping
company. Then, a discrete event simulation model is used to estimate the total wait-
ing time and emission. A simulation-based genetic algorithm is proposed to solve
the problem. Genetic algorithm (GA) is used to find the feasible solutions for the
mathematical model while simulation is used to estimate the quality of the solu-
tions obtained from GA. Based on a case study in a Singaporean port, numerical
experiments are conducted in order to show the relationship between emission
reduction and the number of available periods for delivery or picking up containers.
2 Literature Review
There is a rich literature in the area of truck emissions at a seaport. In this sec-
tion focus is on studies related to truck idling emissions, truck turn time estimation
and truck arrival pattern optimization. Truck idling and emissions are receiving
increased attention, as idling engines operate very inefficiently (about 3 % energy
efficiency compared to 40 % when operating on the highway) and suffer greater
wear and tear (Brodrick et al. 2002 ). Although heavy-duty diesel vehicles produce
low levels of hydrocarbons (HCs) and carbon monoxide (CO), when compared to
gasoline engines, they produce relatively high amounts of NOx and PM. The latter
two emissions are widely considered as the two most serious air pollution threats
(Brodrick et al. 2002 ). Idling emissions differ by trip duration, season, geographic
location, and trucking operation, making it difficult to quantify emission volumes
produced. Some studies address emission factors of specific truck types or specific
locations. For example, the Environmental Protection Agency's MOBILE model
provides emission factors dependent on several parameters, including speed, fuel
type, vehicle age, and ambient temperature (Utts et al. 2000 ); while engine idling
emission factors in POLA are provided by Starcrest Consulting Group ( 2011 ).