# Benefits of Advanced Air Mobility for Society and Environment: A Case Study of Ohio
## 4 Benefit Factors
### BF-4: Time and Inventory Cost Savings in Cargo Delivery by eVTOLs
#### 4.4.2 Lead Time Savings  
The eVTOLs are envisioned to transport large goods and freight to and from airports, distribution hubs, and manufacturers, as well as end-users or consumers. There are five major entities in a supply chain network, namely, suppliers, manufacturers, distributors, retailers, and consumers or users. Once an order is placed by an entity, the time it takes for the entity to receive the goods is referred to as _Lead Time_. Clearly, buyers desire shorter delivery lead times [62]. Moreover, given the increasing demand for e-commerce, lead time has become an increasingly major quantity of interest due to customers' time constraints [63]. Reduction in lead time from an integrated supply chain network indicates the use of faster shipping methods [64]. To assess the monetary worth of the lead time, a survey-based study was performed, where the variables were based on the experience and characteristics of customers in the USA. Relative to a standard lead time of 3-4 days, the findings revealed that customers are prepared to spend an extra $12.80 for delivery today, $8 for delivery tomorrow, and $2.78 for delivery in two days. On an aggregated average, delivery lead time was estimated to be worth $3.61 per day [64]. Based on this, we assumed that the aggregated average Value of Delivery Time Savings (\(VDTS\)) applicable for SMCO in the next 11 years is $3.61 per day. Using the value of \(S_{c_{i}}\) obtained from Equation (20), we calculated the average Annual Value of Delivery Time Savings (\(AVDTS_{i}\)) for year \(i\):  
\[AVDTS_{i}=(S_{c_{i}}\times 30)\times VDTS\qquad i\in\{2022,2023,...,2032(year)\}. \tag{27}\]  
BF-5: Cost and Travel Time Delay Savings for Bridge Inspections 4.5.1. Travel Time Delay Savings for Passengers  
To maintain the structural integrity of bridges in Ohio, they are inspected regularly and on an emergency basis by ODOT. ODOT is increasingly operating sUASs for this purpose. Every year, the ODOT inspects 14,500 bridges at different levels of intensity. Snooper trucks with a bucket carrying inspectors close to the underside of a bridge are used for around 400 inspections every year [31]. We focused on these \(I=400\) heavy inspections for our study. The use of snooper trucks mandates lane closures, and due to this reason, passengers have to face travel time delays. Value of travel time and travel time cost were discussed in Section 4.1. According to the traffic flow analysis conducted by ODOT, the total average hourly volume per lane for Ohio State is 1200 passenger car per hour per lane (\(\alpha\)) is [65]. For our study, we considered one lane closure for bridge inspections. The traditional bridge inspection approach needs on average 8 h per inspection as Traditional Lane Closing Time (\(TLCT\)). In comparison, it takes only 4 h per inspection on average as Reduced Lane Closing Time (\(RLCT\)) if a drone is used. Using Equation (28), the average number of yearly passengers facing lane closure (\(P_{1}\)) due to traditional bridge inspection in Ohio can be computed:  
\[P_{1}=I\times TLCT\times\alpha \tag{28}\] \begin{table}
\begin{tabular}{c c c} \hline \hline
**City** & **Average Base Rent (\$/(sf\cdot month))** & **Average Size (sf)** \\ \hline Akron & \$0.90 & 48,813 \\ \hline Columbus & \$0.67 & 48,215 \\ \hline Cincinnati & \$0.77 & 42,879 \\ \hline Cleveland & \$0.82 & 42,571 \\ \hline Dayton & \$0.99 & 28,581 \\ \hline Toledo & \$0.61 & 26,726 \\ \hline Average for all cities & r = \$0.79 & z = 39,631 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Average rent and size of warehouses in SMCOSimilarly, \(P_{2}\) can be obtained which refers to the average number of yearly passengers facing lane closure due to bridge inspection by drones:  
\[P_{2}=I\times RLCT\times\alpha. \tag{29}\]  
Closing one lane limits the route capacity and causes traffic congestion by creating a bottleneck on the open lane. Based on a review of common practices across the country, the average delay value (\(ADV\)) was chosen to be 10 min per vehicle [66].