# Connected Vehicles: Technology Review, State of the Art, Challenges and Opportunities
## 3 Applications
### Research Potential for Applications
#### 3.3.2 Last-Mile Delivery Services  
The last mile is defined in transportation planning and supply chain management as the movement of goods and people from a transportation hub to a final destination [106]. The growing public demand for online shopping has greatly increased the number of delivered packages by courier, express and parcel services. People tend to order online aiming at fast and more time-efficient delivery services. However, the direct relation between door-to-door delivery and the inefficiency of the last-mile delivery systems has potentially resulted in significant extra miles traveled by diesel trucks, specifically in residential areas. These trucks contribute to traffic congestion, air pollution, higher costs, and low quality-of-life conditions. It becomes even worse when customers are required to sign upon delivery [107,108]. Therefore, innovative solutions for last-mile delivery to decrease the negative environmental impact of the extra miles traveled are becoming a necessity. These solutions include, but are not limited to, cargo-bikes [109], semi- and fully autonomous last-mile delivery, delivery droids (bots), E-palette, postal delivery, driverless deliveries, and privately owned AV. As an example, cargo bikes include the Centaur Cargo Trike XI and Armadillo Volvo's electric cargo bikes [110]. According to McKinsey, semi- and fully autonomous last-mile delivery will reduce costs by approximately 10-40% [111].  
The COVID-19 pandemic has taught us the lesson that our systems are not designed for large-scale emergencies. The high contagiousness/viral shedding of the novel coronavirus is one of the major causes of the outbreak. Social distancing is the main measure taken to reduce the spread of the virus through minimizing the contact between the people. However, frontline workers who treat patients or who deliver medicine or food for them, and even people at home who order essential goods like medication or groceries, are still at risk. Contactless last-mile delivery systems and services can help in avoiding physical contact between caregivers and patients or between delivery workers and the delivery recipients. These contactless last-mile delivery systems will benefit from the rapid proliferation of connected technologies and the recent advancements in semi- and autonomous delivery platforms to revolutionize the urban logistics and to provide safe and efficient delivery methods for medical supplies [112], medications [113], food, groceries, and other goods [114; 115].  
Increasing the efficiency of last-mile delivery can be achieved by decreasing the distance traveled for door-to-door delivery and by lowering the number of packages that are considered as missed deliveries. Innovative ideas such as in-car delivery services have been released by automotive companies, such as Volvo and GM, who have teamed up with Amazon to provide this service. This includes times where customers are not present in their cars. In such cases, the couriers will acquire a unique one-time digital key that can help unlock the customer's vehicle for package delivery [108]. Even though several studies have been conducted on last-mile delivery and cargo-bikes [107; 108; 116; 117], it remains challenging, especially in dense, congested areas and in harsh weather conditions.