Figure 6 : Distribution of the included papers in relation to
the type of vehicle and the energy
Source : authors
From the total of paper considered, 42% proposed bicycle/tricycle as
the best alternative for last mile urban deliveries. Considering these
papers, with regard to the energy used, 64% pointed to electric energy
and 36% to human propulsion. On the other hand, light commercial
vehicles, which are vehicles with a Gross Vehicle Weight (GVW)11Means
the value specified by the manufacturer as the loaded weight of a
single vehicle. The same criterion is used by the Brazilian
authorities. of not more than 3.5 tonnes, were considered in 58% of
the studies, among which 73% of them pointed to the use of electricity
and 27% of them pointed to the use of other sources of energy (diesel
dedicated, diesel/methane and diesel/biodiesel). It is noteworthy that
(Alessandrini et al., 2015) considered the use of an unmanned light
commercial vehicle powered by electricity. (Foltyński, 2014) suggested
the use of bicycles, tricycles and motorcycles together with light
commercial vehicles (all electric), as an alternative for last mile
delivery.
According to (Schoemaker et al., 2006), the number of light commercial
vehicles in Europe has increased by 15% between 1990 and 2003, while
the number of vehicles with a GW over 3.5 tonnes has increased by 6.6%
during the same period. This information demonstrates the tendency to
increase the participation of light commercial vehicles in the urban
freight transport. In addition, according to (Dablanc, 2009) urban
freight transport is inefficient in most cities, including those in
developed countries, with low density rates. For example, in London the
occupancy rate of this type of vehicle varied between 40 and 60% in
2006 (Schoemaker et al., 2006). This practice has also been applied in
developing countries, such as Brazil, where tricycles have been used by
companies like Coca-Cola (Fernandes, 2015a) and Correios (Oliveira,
2015b), which seek to reduce the effects of traffic congestion and
traffic restrictions imposed by the authorities, using sustainable
practices that guarantee the maintenance or improvement of the level of
service.
Therefore, it appears that delivery companies may have a tendency to use
smaller vehicles in the last mile distribution, for example, tricycles
and bicycles, as verified in this systematic literature review. It is
inferred thus a trend, pointed out by the specialized literature, on the
reduction of vehicle sizes used in the last mile, whereby the adoption
of bicycles, tricycles and light commercial vehicles (Table 2).
Nonetheless, it is a logistical challenge to integrate the trend of
reducing the size of vehicles (consequently with lower load capacity) in
the last mile urban delivery with the operation of regional freight
transport that, in pursuit of sustainable and efficient transportation,
uses larger and heavier vehicles, with higher capacity (Alice and
Ertrac, 2015). For this reason, it becomes essential to use
deconsolidation centers around urban areas.
Regarding the type of energy used by vehicles, considering all 26 papers
included in this systematic literature review, it was verified that 69%
deals with vehicles powered by electricity. This result demonstrates the
potential use of electric vehicles in the urban freight transport,
especially in the last mile distribution, since electrification is
widely considered as a viable strategy for reducing the oil dependency
and environmental impacts of road transportation (Weiss et al., 2015).
The other types of energy used in the applications analyzed were:
methane, biodiesel, diesel (23%) and human propulsion (8%).
It is noted that there is a cultural barrier related to the
acceptability of customers for signing contracts with companies that use
a bicycle delivery service (Schliwa et al., 2014). Another barrier
mentioned refers to the cities infrastructure, especially to electric
vehicles power supplies system, and the need for construction of
consolidation centers, in order to facilitate the cargo distribution
using electric vehicles and smaller vehicles.
Regarding the economic benefits, the studies pointed to the reduction
of: energy consumption, delivery time and traffic congestion. The
environmental benefits have focused on reducing CO2
emissions, air pollutants and noise emissions. Referring to social
benefits, it is possible to highlight jobs generation and the
improvement in the quality of life of the population. It is important to
reinforce the conclusions of (Sadhu et al., 2014), which pointed out the
health problems that could be caused by the use of bicycle (human
propulsion) and the excess load weight (some cases about 195 kg).
With reference to the scope of its application, it was possible to
obtain information about the average speed developed by the vehicles
considered in the studies and the cargo capacity, as well as the
characteristics of cities where the studies were applied. The average
bicycles/tricycles speed varied from 2 to 6 km/h (Sadhu et al., 2014),
while light commercial vehicle reached 25 km/h (Gruber et al., 2014).
Regarding cargo capacity, (Gruber et al., 2014) point out the value of
100 kg for capacity on electric bicycles in Germany. (Schliwa et al.,
2014) informs the existence of weight limitation of 60 kg for shipments
on electric-assisted bicycles in England. However, (Schier et al.,
2016), in their survey of the last mile distribution in urban areas,
consider that electric-assisted bicycles and tricycles can carry between
50 and 250 kg. In the case analyzed by (Sadhu et al., 2014), in New
Delhi, up to 195 kg of human-powered bicycles are transported per trip.
Among the included papers, 81% considers a case study or an application
in one or more cities (as shown in Table 3). Berlin, Paris and Tokyo are
the most studied cities. Tokio is a megacity with 13.5 million
inhabitants, Berlin is the fifth most populous city in Europe with four
million inhabitants and a high concentration of economic activities
(Demographia, 2016) and Paris has a high population density (21 thousand
inhab/km2) and high concentration and diversification
of economic activities (Heitz and Beziat, 2016). Only one study
considered a megacity located in a developing country: New Delhi (India)
with 23 million inhabitants, distributed in its metropolitan region.
Although there was a study developed in Brazil, its analysis was
developed in Belo Horizonte, which is not one of the two Brazilian
megacities (São Paulo and Rio de Janeiro). There was heterogeneity in
relation to the population of the studied cities, ranging from 87
thousand to 13 million inhabitants. Moreover, it has been observed that
approximately 70% of the cities present densities above 1,000
inhab/km2. This result was an expected, since the
demand for urban freight transportation is concentrated in densely
populated areas (Heitz and Beziat, 2016).
Table 3. Cities with case studies in decreasing order of
density levels