Chapter 6 TRANSPORT

The type of liquid milk distributed, the packaging system, the number and location of retail centres, the distance between the retail centres and the plant or depots, and the type of vehicles are major factors affecting the techno-economics of transport. In some areas milk is sold only in the morning, in some twice a day and in some others - particularly where refrigeration is available or UHT or sterilized milk are popular - throughout the day. These purchasing habits of the consumers have also to be considered when assessing transport requirements.

In order to work out a comparative analysis of the techno-economics of transport of different types and quantities of liquid milk, simplified distribution models had to be designed. The analysis is made under these model conditions.

The topographic model of the area of distribution is shown in Fig.46. It is assumed that a daily production of 10 000 to 100 000 litres will be distributed within a square 10 km × 10 km and for 250 000 1/day the area to be served will be a square 20 km × 20 km. Focal points around which 1 000 1/day are sold are marked with a cross. They do not necessarily indicate the locations of retail shops, but rather represent the topographical designation of centres of milk sales areas. This implies the assumption that the additional distance which the milk delivery vans have to cover around the focal point in order to reach the actual retail shops is negligible as compared to the distance between focal points and the plant. The analysis of delivery vehicles routeing has been done separately for each capacity and each milk packaging system. An example of this analysis is shown in Fig. 47.

The routeing indicated for the transport is not necessarily the shortest. In a real area access to roads, density of traffic, local regulations, etc. will affect the selection of routes and will certainly deviate from the theoretically shortest. In the model presented, routeings have been selected following a common pattern thus permitting comparisons between different systems and capacities. It was found that the quantity of milk distributed has little influence on specific distance expressed in km/1 000 litres. For practical calculations the specific distance may be considered as constants for each of the distribution systems.

Transport costs of UHT milk are affected by the fact that the expense of UHT treatment and aseptic packaging can only be justified for markets which require a shelf-life of the product of at least 2 months. Such markets include those where distribution involves very long distances or times, i.e. where the processing plant is at a long distance from the retailer. Transportation costs from the plant to a depot in the consumption centre could not be included in the calculations presented since no relative model conditions could be drafted. In this chapter distribution of UHT milk is to be considered as covering transport operations from a depot, instead of from a milk plant. Additional transport costs from plant to depot should be calculated separately according to local conditions.

Fig. 46 Models of distribution areas ( milk plant; + focal points of sales areas)

Fig. 47 Model distribution routes for 10 000 litres/day of pasteurized milk in 1/2 litre glass bottles

The type and capacity of milk distribution vehicles cannot be standardized beyond certain limits, since requirements are different for different systems. A prime-mover with a chassis of 5 t carrying capacity was selected as standard. On this standard chassis three types of body may be placed according to requirements:

1. a closed uninsulated chamber for UHT and sterilized milk;

2. a closed insulated chamber for all pasteurized milks, except for delivery to vending machines;

3. an insulated milk tank for deliveries of pasteurized milk to vending machines.

The milk-carrying capacity of the chassis was calculated excluding the weight of the appropriate body. It was also assumed that the required platform area may be chosen without affecting the costs of the chassis.

Standard timings of milk delivery to retail centres have been adopted as follows:

1. Pasteurized milk to vending machines, UHT milk and sterilized milk are delivered during two 8-hour shifts, since the products can be kept safely in the retail centre.

2. Pasteurized milk is delivered to retail centres within one 8-hour shift. Empty bottles and cans are collected during the second 8-hour shift.

3. Empty sterilized milk bottles and crates and the crates for pasteurized milk in single-service containers are collected during delivery trips.

No door-step delivery system was analysed in this study. Simultaneous distribution of milk and collection of empties for pasteurized milk in bottles and cans is generally considered as impractical in conditions prevailing in developing countries as the lack of refrigeration necessitates sales during a short time and whole-day storage of uncollected empties at the retail centre is undesirable.

In order to arrive at comparative costs for the various packaging systems studied it is necessary first to identify a number of basic factors and to evaluate these for the model transport systems outlined above. These factors can be considered in groups.

The numerical values ascribed to these factors for the purpose of this analysis are given in Table 13.

Table 13 Model values for Group 1 factors

The numerical values ascribed to these factors for the purpose of this analysis are given in Table 14. They are based on practical experience.

Table 14 Model values for Group 2 factors

Group 3 - Other factors

The following factors may be considered constant for all systems. The numerical values given below are based on practical experience.

The following equations have been formulated to characterize the techno-economics of transport. In these equations the symbols a and A have been used to represent the quantities of milk in thousands of litres distributed per day and per year respectively.

Total number of vehicles

      … (1)

Note t₃ should be included only when distribution and empties collection are simultaneous. Specific working time of vehicles - hours/1 000 1

      … (2)

Labour requirement hours/1 000 litres T_m = T_vm        …(3)

Average lifetime of vechicles - years L =       … (4)

Depreciation * D =       … (5)

Interest on capital* I =       … (6)

Maintenance* M =       … (7)

Taxes and insurance* R =       … (8)

Fuel costs* O =       … (9)

Labour costs* W = C_w T_m         (10)

* In currency units/1 000 litres. Symbols C_v, C_o, C_w represent costs of one vehicle, one litre of fuel and one hour of labour respectively in any currency units applied.

The equations presented above may be considered as having relatively universal application. In this model analysis, the values estimated for N, T_v, T_m and L are given in Table 15.

Table 15 Model values for N, T_v, T_m and L

The costs in US$ indicated in this model analysis have been calculated with the assumptions that one hour of labour, C_w, costs US$ 0.70 and one litre of fuel, C_o, costs US$ 0.15. The value of C_v has been calculated by estimating the cost of a prime-mover with a 5 t chassis at US$ 15 000. This value was increased by a coefficient ‘y’ to adapt the chassis to the respective requirements of milk transport. The various transport costs calculated from equations (5) to (10) above in US$/1 000 l are given in Table 16.

Table 16 Specific transport costs

The above analysis indicates that specific values of different transport cost components, that is, cost per 1 000 litres of milk, are almost constant, i.e. not dependent on the quantity of milk distributed but related basically to the system of milk packaging and distribution. This agrees with figures obtained from operating plants. It reflects the fact that the carrying capacity of a single transport vehicle is relatively small compared to the quantity of milk distributed. This results in a high degree of transport equipment utilization and, finally, in constant specific values within each system. The term ‘constant’ should be considered as expressing the absence of a trend towards increase or decrease of specific values. In the lowest ranges of quantities of milk distributed the various specific values are usually slightly higher, but the difference appeared insignificant for the purpose of this analysis.

Although the specific costs of milk distribution transport as presented above in US$/1 000 litres are valid only under the model conditions described, several observations resulting from this study have a wider application. They may be listed as follows:

1. The most expensive is the distribution transport of pasteurized milk in bottles; the cheapest is tanker transport to vending machines followed by UHT-treated milk in single-service containers transported in non-returnable plastic wrapping. The transport costs for the other systems do not differ substantially from one another.

2. In the total transportation costs expenses on fuel play a minor role in all systems.

3. In order to make the transport system reliable, a relatively high capital input is required resulting in a theoretically long life for vehicles.

4. A substantial proportion of the total costs may be represented by labour expenses.

The equations formulated for calculating different factors affecting milk distribution transport can be applied under conditions different from those presented as model in this study by using the appropriate numerical values.