Evaluating the impacts of using cargo cycles on urban logistics: integrating traffic, environmental and operational boundaries

The increasing urbanization, population growth and changes in the goods’ demand patterns favoring just in time solutions, combined with the reduced stock in stores, has led to increasing freight movements within cities. As a result, urban goods distribution has been associated with negative impacts mainly related with traffic congestion of commercial vehicles, as well as of the road capacity reduction caused by frequent stops for loading or unloading operations, which results in lower energy efficiency and higher emissions profiles [1‐3].

Under such unsustainable context, society is demanding public administrators’ to promote the sustainability of cities, to guarantee mobility and quality of life, while ensuring an efficient urban goods distribution system [4‐6]. While pursuing effective policies to achieve these goals, various measures and initiatives have been recently promoted and tested, namely the introduction of light electric vehicles for urban logistics purposes [5, 6]. The fact that more than 80% of freight movements in European urban areas are of distances below 80 km [7], added to the target of emission free city logistics by 2030 [8], has put light electric vehicles in the public agenda as a possible alternative that can help in this direction.

Light electric vehicles are defined as battery, fuel cell, or hybrid-powered 2-or-3-wheel vehicles generally weighing less than 200 lb (100 kg). Examples of light electric vehicles are small electric vehicles (SEV), electric cargo bikes and electric cargo tricycles. These vehicles rely on a more efficient propulsion technology and result in lower local emissions and reduced noise compared to conventional vehicles. In what refers to its operational costs, light electric vehicles are associated with benefits over larger conventional diesel vans and trucks on taxes, insurance, storage and depreciation costs. Additionally, light electric vehicles are also easier to park than vans or trucks and are viewed as less intimidating and safer by the public. Furthermore, they allow the reduction of the total curbside space occupied by vehicles making on-street deliveries, further reducing the impact of unloading operations on traffic congestion [3]. The use of smaller vehicles also results in fewer conflicts with other road users as is easier to overcome those [5].

Nonetheless, these vehicles are still struggling to be widely accepted by the urban logistics’ industry. There is a valid argument that downsizing vehicles typology can lead to “penalty costs” of unsatisfied demand due to the weight, volume limitations as well as distance range of these vehicles [9]. The strong resistance from operators towards this solution, as well as the disproportionate enthusiasm by public administrators and politics, are not supported by the scientific literature on the real impacts, potential market share and geographical scope of light electric commercial vehicles.

The use of light electric vehicles for urban logistics purposes, namely small electric four wheel vehicles, has already been approached by the authors in previous works [3, 10, 11]. Along that research, it was demonstrated that light commercial vehicles are appropriate as a niche of market complimentary to conventional vans. It was identified a limit of up to 5% of conventional vans that could be replaced by those vehicles at the city level, without causing relevant traffic disturbances and operational restrictions. The geographical coverage where light electric commercial vehicles could perform in order to be economically competitive and lead to a sustainable mobility was set to a limit of 12 to 30 blocks corresponding to a maximum linear distance of 2 km (1.2 miles), with a replacement rate of 1 SEV: 1 van. Within this pre-defined spatial limit, light electric commercial vehicles, SEV, could replace up to 30% of the conventional vans operating within that distance range.

Along this paper, the authors assess the impacts of light electric commercial vehicles, namely of electric cargo bikes, from a public policy perspective and, simultaneously, taking into account variables that cover the urban logistics operators’ interests. Under a public policy perspective, the considered variables evaluate mobility, environmental impacts and indirectly, the quality of life. In terms of private interests, the studied variables cover costs levels (operation and driving), service levels and efficiency. This evaluation aims at clarifying if electric cargo bikes can indeed represent a sustainable mobility policy under specific boundaries, by leading to better environmental and social impacts and not hindering the operational efficiency of urban logistics activities.

Cycle logistics have risen as an attractive concept for urban areas, with high potential of reducing energy and environmental impacts [12]. Cycle logistics refers to professional logistics like delivery services, waste collection or small trade services using cargo bicycles (2, 3 or 4 wheelers either electric or conventional) and bicycle trailers. The specific use of electric cargo bikes in cycle logistics presents advantages within urban logistics operations, such as less driver fatigue and higher payload due to the electric assistance help in moving the vehicle. They are particularly suited for urban goods distribution, for last mile deliveries associated to short distances or incorporated in innovative logistics systems, such as micro-consolidation centers (demonstrated in London [13]) or mobile depots (e.g. in Brussels [14]). A good example of the use of cargo bikes is implemented in Paris, with an increasing number of cargo bikes for last mile deliveries [15], which has led to a strong growth of this niche market [16]. 60 freight related EV demonstration projects in the Baltic states have been identified [17], with cargo bikes being used as “accompanying modules” (for example, in retail deliveries in Hasselt, Belgium, and postal deliveries in Brussels, Belgium). In spite of the growing examples of the use of electric cargo bikes in the literature, the correct number of electric cargo bikes in use is uncertain [18]. The same goes to its unclear economic operational feasibility [19], since the higher purchase cost and respective recharging requirements may not overturn the lower operating costs per kilometers when comparing similar electric and conventional vehicles.

Research has assessed the use of electric bicycles mainly applied to private transport users rather than for urban logistics purposes. Gruber [18] studied the typical profile and potential to reject new vehicle technologies of individuals and decision makers concluding that factors such as electric range, purchase price and availability of information are essential to enable the adoption of this alternative. These factors are commonly used to justify the urban logistic operators’ resistance to change to electric vehicles revealed in other studies [3, 11]. Borgaray [20] modeled the quality perceived by users from public bicycle systems through the use of Probit models, concluding that safety and information have the greatest impact on public bike users’ perceived quality. Safety is also one of the most important concerns with the use of bicycles in city logistics, since cyclist constitute a vulnerable road user because they have problems being seen and have increased difficulties in undertaking avoidance maneuvers and understanding the movements of other vehicles [21]. Additionally, the cyclist’s safety as well as the weather conditions in which they must drive without damaging their cargo, can also be determinant factors that justify urban logistics operators’ resistance towards the adoption of cargo bikes.

Besides the studies on users’ acceptance, scientific literature has also approached the topic focused on the system supply characteristics and its optimization. Anderluh [22] evaluated a two-echelon city distribution scheme with temporal and spatial synchronization between cargo bikes and vans based on a greedy randomized adaptative search procedure with path relinking. Authors concluded that costs and emissions can be saved by the combined usage of cargo bikes and vans instead of vans alone. Dell’Olio [23] estimated the potential demand of a public bicycle system and the optimization of pick-up and drop-off point’s locations. Lin and Yang (2010) also proposed a methodology for estimating the location and number of docking stations needed for a given system. The translation of these analysis into urban logistics would lead to the estimation of the location and the number of proximity delivery consolidation centers from and to which electric cargo bikes would run. Melo [3] defined the limit to maximum linear distance of 2 km (1.2 miles), when considering the use of small electric vehicles for urban logistics purposes. Further studies should be performed to define the distance range within the city where electric cargo bikes can perform in conditions to lead to a sustainable mobility. Additionally, the network can only accommodate a limited number of electric cargo bikes due to its intrinsic physical characteristics in order to guarantee the same supply reliability and traffic performance within the area. Melo [10] identified a limit of up to 5% of conventional vans that could be replaced by SEV’s at the city level, without causing relevant traffic disturbances and operational restrictions. Policy makers must be aware of these boundaries in order to promote effective sustainable mobility policies in a realistic and successful way. Along the case study presented on the following section, the authors estimate the effects of downsizing urban logistics vehicles without penalty costs of unsatisfied demand in a specific area within the city. The effect of replacing vans by cargo bikes is analyzed, considering public and private stakeholders’ interests, in a case study carried out in the city of Porto (Portugal). Changes on the distance travelled, energy consumption and CO₂ emissions as well as on running costs are also discussed.

The use of light electric commercial vehicles, namely electric cargo bikes, is likely to become a reality in the coming future. The usability and the effectiveness of light electric vehicles greatly depends on their ability to satisfy the local logistics demand and reduce traffic disturbance and its impacts. Taking into consideration the lack of studies that quantify the overall effect of such systems, this paper addresses the following questions:

When analyzing the overall traffic performance indicators, it becomes clear that the replacement of conventional vans by electric cargo bikes should only be promoted to a certain extent. In Fig. 3, it is visible that replacing 3, 5 or even 10% of freight movements by electric cargo bikes in the study area can lead to a better traffic performance. The speed slightly increases in relative terms, although its absolute variance is not significant (<1 km/h). Additionally, there is a decrease in delays of up to −4%, correspondent to a minor difference of 3 s per km.

To explain these results, it is necessary to highlight that electric cargo bikes are easier to overcome in traffic due to its dimensions (either circulating or parked for unloading activities), but simultaneously impose a lower speed compared to vans. What happens in the three scenarios with up to 10% of the share of light freight movements is that the positive effect of using electric cargo bikes is more relevant than the speed restriction. That is particularly relevant in the case of buses, the vehicle typology that registers the higher relative reductions of delays in the overall area for those scenarios and due to its intrinsic characteristics can easier overcome cargo bikes than vans (as presented in Fig. 4).

Traffic simulation results show that if the mobility criterion to be used is the ease of movement, then electric cargo bikes are limited to a niche of market up to 10%. Such boundary is also conditioned by the geographical range of movements, already defined in previous research for this area as a maximum of 2 km of linear distance [10]. The fact that electric cargo bikes can replace up to 10% of conventional vans movements within delimited areas in the city suggest that tailor-made solutions for urban logistics can be promoted by specific mobility policies.

Complimentary to the traffic performance analysis, an environmental quantification was performed for the different replacement rates. Figure 5 shows that variation both for all the stakeholders (Fig. 5a)) and for the urban logistics operators running on commercial vehicles (Fig. 5b)) of WTW energy consumption and CO₂ emissions. For urban logistics operators which includes vans, trucks and electric cargo bikes, up to 73% of CO₂ emissions can be avoided, which represents 129 to 746 kg of CO₂ avoided emissions from Scenario 3% to Scenario 100%. When observing the fuel and environmental effects, the results in WTW energy consumption and CO₂ emissions are also positive for all the simulated replacement shares (Fig. 4a) and for the urban logistics operators (Fig. 4b). For urban logistics operators (which includes vans, trucks and electric cargo bikes) up to 73% of CO₂ emissions can be avoided, which represents 129 to 746 kg of CO₂ avoided emissions from Scenario 3% to Scenario 100%.

It is necessary to state that the Scenarios of 20, 30 and 100% penetration of electric cargo bikes lead to worse traffic conditions and, therefore, register longer queues for all type of vehicles, longer delays (up to 84%, corresponding to differences of more than 1 min per km) and longer idling times compared with the baseline scenario. Such conditions have negative effects in terms of environment, but the benefits that occur because of the replacement of vehicles are much higher and, therefore, even for the scenarios with worst traffic performance there are fuel savings and lower CO₂ emissions. The higher share of the electric cargo bikes is directly associated with the decrease of the share of conventional vans, which unavoidably means that there are fewer vehicles polluting.

The conversion of fuel savings into monetary costs results in reductions that vary from 50 to 266€ for the sum of the urban logistics operators running in the area (per hour) and from 284 to 747€ for all the traffic system users (including passenger, public and freight transport), as presented in Fig. 6. These values refer to the morning peak hour and provide evidences that the replacement of conventional vans by electric cargo bikes have a positive effect in the environment and on fuel savings. The impact in terms of driving costs is negative due to the additional driving time, registering additional costs of up to 0.13 € per hour for urban logistics operators. When comparing this penalty with the fuel savings, the running cost is still significantly positive for their operation.

When looking to the public stakeholders’ perspectives, under an analysis of the external costs, the introduction of electric cargo bikes for urban logistics activities has positive effects for all the vehicle categories and all the scenarios reaching up to 25% of reductions in external costs. In the overall network, the effects in the external costs correspond to average monetary reductions of 0.06 € per vehicle per hour.

The use of cargo bicycle for urban logistics appears as one promising solution for congested and polluted urban centers. Despite the increasing promotion of cargo bikes in urban logistics by public stakeholders, there are still some reservations from urban logistics operators to its adoption. Operational issues are supporting these reservations. One of the main issues is that cargo bikes can only cope with parcels and not pallets and, consequently, can only cover specific types of business. The size and weight of parcels or mail are rather small and the travel distance must be short. Moreover, it implies the existence and availability of a consolidation centre – can be a post office station – from where the cargo bikes depart. Added to these operational limitations, there are also considerable issues of the still difficult maintenance, a small second-hand market, and an insufficient number of recharging public facilities. Nonetheless, accurate quantifications and ex-ante assessment of its potential impacts need to be performed to better design policies that fit in cargo bikes intrinsic characteristics and simultaneously allow overcoming the mentioned obstacles. For that purpose, a case study in the city of Porto, Portugal, was developed to estimate the effects of replacing vans by cargo bikes to deliver parcels at a pre-defined limited spatial coverage.

This research follows previous works from authors [3, 10, 11], that had already identified that the geographical scope of the implementation of light electric commercial vehicles is not the city level, but rather specific areas within the city with maximum linear distances close to 2 km. Starting from that assumption and because at that spatial level of analysis and the observed delivery patterns allowed it to be carried out using cargo bikes, with a replacement rate of 1:1, this paper tried to understand if the current focus and investment that is being promoted by public policies in this type of vehicles can actually promote the public good interests and private stakeholders’ efficiency and in what conditions can it be implemented. The results of this paper show that electric cargo bikes can leads to better environmental and social goals, while assuring the same level of operational and traffic performance on urban logistics. Results from simulation show that the conditions in which cargo bikes can help to achieve the concept of sustainable mobility are limited to what can be considered a niche of market. There is a mobility limitation that establishes as a boundary the 10% of electric cargo bikes in freight movements for the studied area within the city of Porto. Such boundary should be explored and clearly defined by public stakeholders prior to the implementation of exclusive areas for these vehicles in city centers. Adding to the results of this paper, cargo cycles are not a costly solution and have the potential to be easily integrated with local last mile solutions, such as the ones generated by e-commerce. Additionally, the fact that drivers do not need a driver’s license are factors to influence operators’ perception on cargo bike requirements in a positive perspective.

Ultimately, the use of electric cargo bikes can play a relevant role to local administrators to achieve the concept of sustainable mobility in specific delimited areas of a city. The success of its implementation will depend of an integrated strategy with private operators for the promotion of this solution and the prior delimitation of the conditions in which it actually leads to improvements in terms of mobility, environment, energy, running costs and externalities.