Logistics heavyweights are clearly interested in Tesla's promise to slash total cost of ownership and per-mile expense.

Tesla's electric semi has continued to attract attention from big players in highway logistics, prompting UPS to secure a place in line with a pre-order for 125 trucks.

The order is said to be the largest yet, following on the heels of a 100-unit commitment from PepsiCo, according to Reuters. Other deposits have been received by Walmart and JB Hunt, among other companies.

UPS plans to deploy a Tesla semi fleet on an experimental basis to determine if the California-based automaker can deliver on its bold promises to reduce costs compared to diesel rigs.

"We have high expectations and are very optimistic that this will be a good product and it will have firm support from Tesla to make it work," says UPS' senior global director for automotive maintenance and engineering, Scott Phillippi.

Most headlines have focused on the semi's claimed zero-to-60 mph time of just five seconds. Fleet operators presumably shrugged off the performance claims and futuristic styling, instead salivating over Tesla's target for operational costs of just $1.26 per mile compared to more than $1.50 for diesel.

A $0.25 savings may seem like pocket change but quickly adds up as the odometer climbs. UPS drivers log more than 3 billion miles annually, equating to a savings of $750 million if the company could achieve a quarter-per-mile reduction across its entire vehicle fleet.