Forecasting of Freight Demand Transportation (Case Study in Lampung Province, Indonesia)

Forecasting the volume of freight has a significant importance for future decisions for the entire economy, as well as its individual participants. The transportation of goods between Sumatra and Java using the highway mode that accumulate with local transportation will greatly burden roads in Lampung province. This research was conducted to predict the pattern and amount of movement of goods in the future. The modelling is conducted for the plan period up to 20 years based on growth predictions of geographical, social, economic and traffic flow. This study conducted a process of Sequential Demand Model (Planning Model 4 stages) by using software Transplan Version 8. Transportation patterns in 2040 is predicted will be dominated by continuous trips with domination of movement from Java to South Sumatra, or otherwise. Both the transportation between internal zones and external zone to internal zone have a significant increase. The most strategic main line freight in Lampung for today and in the future is along the Bakauheni-South Sumatra and Bengkulu-South Sumatra both through toll roads, national roads, and railways.


Introduction
Forecasting the volume of freight has a significant importance for future decisions for the entire economy, as well as its individual participants. The size of transport is dependent on various factors and therefore more accurate forecasts require complex forecasting tools. However, for initial assessment the use of older simple models is sufficient; for example, Holt-Winters double exponential smoothing. They are widely used today in many areas of science, because of ease ofuse and low values of forecast errors. However, to this day such methods are still undergoing refinement. In article [1] the authors justify the need for adjustments in the Holt-Winters double exponential smoothing. In article [2] the authors present a selection method of parameters of model exponential smoothing, which are solved by the minimization of the problem. In [3] the authors of the most commonly used techniques for smoothing such as moving average or exponential smoothing. They specially designed weight coefficients which were employed for smoothing the forecast.
Currently, forecasting models are often supported by artificial intelligence methods. In article [4] the authors applied immune algorithm for estimating the optimal coefficients of logarithm support vector regression. In [5] neural networks of the Autoregressive Integrated Moving Average (ARIMA) method was used to reduce the sensitivity to input errors. In [6] the Bayesian network was used to predict the stock price. The future of road transportation development impacts investment decisions of companies. An interesting approach to the use of forecasting in the supply chain optimization is described in [7]. The article presents the optimization of the supply chain cost by methods of integer programming. Data needed to optimize the production capacity and warehouse inventory is obtained by forecasting using the method of exponential smoothing. A lot can be found in literature on the use of forecasting in the fields of transport. A guidebook [8] has been compiled for those involved in transport planning. It provides a number of forecasting techniques.
The purpose of this study was to determine the pattern and the amount of movement of goods in the base year and the next few years, therefore the needs of the facilities which must be provided can be known to anticipate these developments. This study used a period of up to 20 years, which means that the results of this study can be used up to 2040 with the stages are: 2020-2025, 2026-2030, 2031-2035 and 2036-2040.

Research Methodology
Conventional transport models was used for prediction of traffic demand. The modeling is conducted for a period of up to 20 years where the traffic load adjusted for origin-destination matrix of the associated zones that have been adapted to the level traffic growth of modeling results. The results of the modeling include the prediction of traffic volume and traffic performance predictions in the future.
A process Sequential Demand Model (Planning Model 4 stages) was done in this research. The use of this model is based on some considerations: firstly, it is easy to control on each stage of the work; secondly, it has higher accuracy related to the simplification process is very limited when compared with the Direct Demand Model; thirdly, this model is very flexible to be applied to new cities studied ; and finally, it is in accordance with the ability of a computer program provided by the TRANPLAN Version 8.
Steps to run the program for TRANPLAN as follows: a) Creating and loading freight road network is not the route (Highway Network); b) Make a trip freight distribution as input on the process of loading; c) Imposition into the road network (Equilibrium highway Load); d) Make transyt network, the network of public transport routes in the route); e) Creating route network path (Build Path Transyt); f) Creating origin-destination matrix with public transportation; g) Imposition (Transyt Loading).

Data and Instrumentation
Several parameters were taken and adapted to the statistical report of the Central Statistics Agency (BPS) and the reports from the relevant authorities. Meanwhile, data from the primary survey more widely used in the process of validation and adjustment of multiple parameters.
The data used as input in the development of the model, are: a) The data of land use and zoning administration as a basis for establishing the zone trip system b) The data of Prior OD Matrix. In this case, using the data from the origin-destination survey, OD data in 2018, and secondary data from the results of previous studies; c) The data of condition of transport infrastructure, including: rail networks, stations, road networks, traffic management system, as a basis for the development of the transport network models; d) The data of population distribution, income, vehicle ownership, land use, PDRB, and data traffic as input for the attraction estimation and trip distribution as well as the validation OD matrix.
The study area is divided into several zones. For convenience, the zoning is based on administrative boundaries. Thus in this analysis defined 30 zones consisting of 27 internal zones and 3 external zone as shown in Figure 1. Lampung province road network is divided into 30 zones, 1758 nodes and 4580 roads. Roads were included in this study are arterial roads and collector roads. Inlet and outlet is divided into three, namely the entrance of Bengkulu, South Sumatra, and from Java. Lampung province road network model is in autocad format then was entered into the base data as input Transplant program ( Figure 2).

Freight Transportation in Base Year
In 2020 the average production of travel goods for each zone approximately 792 344 tons / day, with Bandar Lampung as the largest origin and destination of goods in Lampung province for 131 020 tons/day. In percentages, the movement in Bandar Lampung approximately 16.5% of the whole movement in Lampung province. Followed by Java amounted to 90,322 tons/day or 11.4%, and South Sumatra for 58 507 tons/day or 7.4% of the total freight movement in the province of Lampung and then Metro for 50 856 tons/day or approximately 6.4%.
Based on data generation and attraction, Origin Destination Matrix for goods is predicted for the year 2020 to 2040. This matrix noticed the vehicle travel patterns between regions. This matrix is processed from the origin destination survey (road side interview) and the results show that Bandar Lampung is the center of attraction which is become the destination from many surrounding areas. After that MAT is loaded to the road network in order to see the pattern of movement of passengers and goods in the road network. Based on the analysis of the survey results of OD national and other sources, there is information on the distribution of travel demand of goods to every available moda, shown on the image above. The prediction of this the moda use is intended only for the freight movement overland via the internal network in the area in Lampung where external movement generally to Java and Sumatra uses road modas, while to all other areas by sea. It appears that the current freight transport is still dominated by trucks on the highway, while the railway transport only accounts for no more than 10%. IOP Publishing doi:10.1088/1757-899X/1232/1/012008 5 Ideally, with the railway network development scenarios, as well as the utilization of the rail line, in the future the freight transport needs should be more accommodated by train. This is because train is much more efficient than road transport with trucks in case of the time and expense for regional freight movement.
Reducing the burden of road network in the future for Lampung province is an important strategy. This is because the condition of existing the road network in the province within the next 10 years will face big problems such as traffic congestions. Therefore the railways development is a good solution to overcome this problem and also to encourage the development marine transport system scenarios. The imposition of provincial road network is relatively evenly and provide a relatively equal access to all parts of Lampung. That pattern can provide support for the achievement of room development which is more proportional, particularly for areas of the West Lampung and the East Lampung.
To assess the performance of the road network, use indicator of the volume of traffic per road capacity, which is known as Volume-Capacity Ratio (VCR).

Prediction of Transportation
The movement of goods is projected for the next 5 years and so on up to the time of planning, which is 30 years old. Based on this projection could be seen the amount of movement which is happened, so that if it is charged to the road network, the road network that need to be addressed will be known, as well as its relation to other modas. From the desire line in 2025 can be seen the amount of movement that occurs increased about 1.2 times of the movement in 2020. But the movement pattern was relatively similar with patterns in 2020.
The amount of continuous movement is going greater with the domination of the movement of Java-Sumatera, or otherwise. The amount of movement between the zones of internal and external zone to the internal zone is also seen to increase. This will burden the existing road network in the province of Lampung.
Existing trip patterns are also predicted for the next few years, and it can be seen that the increase of movement amount happen on every street. The pattern has not changed much, but the increase of amount of movement can be seen.
In 2025 the movement pattern is predicted to increase with biggest road loading on link of Bakauheni -Bandar Lampung , amounting to 393.606 tonnes/day, followed by Tanggamus towards Liwa for 393.274 tonnes/day. The movement of goods through Lintas Timur is at 265.665 tonnes / day, up to the road to South Sumatra. Another problem faced is the movement of regional which across Lampung province. The high volume of regional movements with the origin and destination regions outside Lampung has created road damage in Lampung province.
In 2030, the movement patterns of freight is predicted to increase with biggest road loading on link of Bakauheni -Bandar Lampung at 496 402 tonnes/day, which has an increase of 100.000 tons / day from the previous 5 years. Followed by a link of Tanggamus to Liwa at 383.463 tonnes/day. The movement of goods through Lintas Timur is accounted for 308.861 tonnes/day, up to the road to South Sumatra. Several roads are in good condition so it can be passed by heavy vehicles without causing any damage. While some other roads were only able to be passed by vehicles which have axle loads is not too heavy, as a result, the transport of goods by heavy vehicles can only be served by certain road sections. In several sections, the traffic network is passing through the unfavorable geographical conditions and it needs alternative pathways to accelerate the trip.
Based on the characteristics of the transport of goods, it consists of industrial and agricultural / plantation transportations which use the moda of medium truck and pick-up. This indicates that the the transport of goods use vehicles which have medium axle load. This is because the center of industrial and agriculture/plantations are the areas that can only be reached by small-medium vehicles.
The condition above gives an overview of types of freight transport required by Lampung province, namely the transport of goods by vehicles having small-medium capacity and significant numbers (as evidenced by the amount of movement frequency is every day), so that it can reach out to all parts of Lampung. This provides an advantage, because network traffic required must not use the road with high bearing capacity, but the road can serve small-to-medium vehicles well and can reach out to all corners of the region.  It can be seen from the figure that the VCR value for the segment of Bakauheni to Bandar Lampung through the existing road is 0.89. Meanwhile, if the toll road is built, then the value of the VCR is turned into around 0.49. Value VCR roads connecting Bandar Lampung towards Pringsewu also increase to 0.66, as well as through Lintas Timur for 0.53. We can also see that the movement of traffic from Terbanggi towards Kotabum has VCR value by 0.55 and from Sumberjaya towards Liwa by 0.52. In addition, the value of VCR from Menggala towards Mesuji around 0.42.
In 2030 the movement of goods is predicted to spread evenly with the value of VCR of Bakauheni towards Bandar Lampung ranged from 0.81 to 0.9. VCR value for the segment towards Bandar Lampung Tanggamus around 0.79. The value of VCR for the transport in Lintas Timur varied by 0.44 to 0.7. The substantial movement is also evident in link of Bandar Jaya towards Padang Ratu with VCR value of about 0.6, as well as the road linking Kenali and Liwa has the traffic volume at 0.56 The increase of movement in 2035 can be seen more clearly with the indicator value of VCR (road performance) as presented in Figure 17. The biggest changes of the value of VCR between 2030 and 2035 is the freight movement of Bakauheni towards Bandar Lampung which ranged from 0.9 to 1.52. This shows the road has been in a critical condition, eventhough some of traffics is divided trough toll road with VCR value of 0.61. In 2035, the movement of goods through the Lintas TImur has VCR value varying from 0.62 to 0.80.
While the roads of Bandar Lampung towards Tanggamus still has VCR value around 0.79. A substantial movement is also evident from Bandar Jaya towards Padang Ratu with VCR value of about 0.7. As well as road connecting Kenali and Liwa has traffic volume around 0.64, or has a slight increase from 2030.
The biggest changes of the value of VCR between 2035 and 2030 is the freight movement of Bakauheni towards Bandar Lampung which ranged from 1.0 to 2.27. This shows the road has been in a stagnan condition, eventhough some of traffics is divided trough toll road with VCR value of 0.80. In 2040, the movement of goods through the Lintas Timur has VCR value varying, with the highest VCR is 0.87. While the roads of Bandar Lampung towards Tanggamus still has VCR value around 0.82. A substantial movement is also evident from Bandar Jaya towards Padang Ratu with VCR value of about 0.91. As well as road connecting Kenali and Liwa has traffic volume around 0.89, or has a significant increase from 2025.

Conclusions
The conclusions that can be drawn from this study are as follows: 1) Most of the movement of goods in the base year (2020) through the national road from Bakauheni to Bandar Lampung, and continue to the Central Lampung were then divided into two directions, namely through Lintas Tengah and Lintas Timur toward South Sumatra.

2) The movement of freight in Lampung Province (both between internal zones and external zones)
is dominated by moda of trucks on the highway, while the railway transport only accounts for no more than 10%.
3) The pattern of freight movement in 2040 is predicted that the domination of continuously movements from Java to Sumatera or otherwise will be greater. The number of movements both between internal zones and between internal and external zones will increase significantly. 4) Until 2040, the transport of goods from Java to Sumatra (inter-urban) were still dominant. It can be concluded that the main line of freight transport in Lampung, which is most strategic for now and in the future, is along the Bakauheni to South Sumatra and also Bengkulu either through toll roads, national roads, and railways. .