What ratio did the packaging engineer or logistics software developer optimize for economic viability?

Density-to-duration ratio

The economic viability of last-mile cold delivery hinged on solving the equation where heavy cooling elements increased freight costs. Traditional methods using abundant dry ice met the required duration (e.g., 12 hours below -18°C) but made the packages too heavy for efficient volume shipping via vans. The key breakthrough, often driven by packaging engineers or logistics software experts, was optimizing the relationship between how much cooling power could be packed into a given volume and how long that cooling effect would last. This optimization is precisely the density-to-duration ratio. By engineering specialized packaging, like multi-layer, vacuum-insulated panels paired with eutectic plates, they managed to drastically reduce the weight and size of the necessary cooling element while maintaining or extending the required temperature duration, thus enabling carriers to maximize the revenue-generating product carried per single delivery trip.