The 440 kWh battery in the 35-foot (10.7 m) electric bus impresses

Proterra boasted that another version of its electric buses completed the Altoona tests to independently prove performance.

The latest model tested at the Altoona Bus Research and Testing Center was the Proterra Catalyst E2 35-foot (10.7 m) with the biggest battery pack (440 kWh) ever tested by Altoona in a 35-foot size.

The press release doesn't contain any further details, but we can assume that the range of 300-400 km (186-250 miles) is possible in the real world. The official specs at the company's website say 251-302 miles.

"Proterra is the only manufacturer that designs transit buses to be electric from the ground up. The purpose built design of the Proterra Catalyst places batteries beneath the floor of the bus and outside the passenger compartment, with the option for additional battery packs on the roof. This distinct design creates a low center of gravity and enables more energy to be stored on board to increase power and range. With more energy on board and best-in-class fuel efficiency, Proterra vehicles continue to be ready to meet the daily mileage needs of nearly every transit route on a single charge. Proudly designed and manufactured in Silicon Valley, Proterra battery systems are lightweight, compact, safe and powerful. Proterra battery packs are made of strong and lightweight ballistic-grade materials designed to withstand the toughest conditions through rigorous battery and vehicle testing and validation programs." "Proterra has tested more battery-electric vehicles at Altoona than any other manufacturer and was the first electric vehicle manufacturer to complete Altoona testing with a battery-electric bus. Proterra also has a history of setting industry standards. Previously, the Proterra Catalyst® E2 Max bus exceeded the world record for driving the longest distance ever traveled by an electric vehicle on a single charge."

Proterra CEO Ryan Popple said: