USPS has touted its Next Generation Delivery Vehicle as part of its 10-year $40 billion investment strategy for upgrading and improving the way the USPS works, but a report from the Washington Post details how delays with the manufacturer producing the trucks have put the implementation of the vehicles behind schedule.

USPS announced two years ago it would acquire 45,000 NGDVs as part of the 106,000 new vehicles it would use to modernize its fleet of delivery vehicles — part of a larger $9.6 billion investment in vehicle modernization. The NGDVs began being used earlier this year, earning positive reviews from mail carriers, but the report says far fewer have made it to the postal routes than was expected at this point.

USPS was expected to have 3,000 NGDVs by now, but the agency reportedly has only received 93 trucks from manufacturer Oshkosh as of November.

Oshkosh has allegedly had problems calibrating the vehicles’ airbags and with leak tests, which have slowed production. The report also says the company can only produce one vehicle per day at its factory, much less than the 80 vehicles per day it had hoped to be pushing out of the South Carolina facility by now.

The implementation of EVs into the USPS fleet was partly funded by the climate provisions in the Inflation Reduction Act, which President Joe Biden had touted as one of his major policy accomplishments. The Postal Service has said the new vehicles are “environmentally friendly and cost-effective.”

“Under our plan, letter carriers in every state will be able to deliver mail and packages using new and modern vehicles within the next five years,” Postmaster General Louis DeJoy said in a statement earlier this year. “These new vehicles are enhancing safety for our employees, improving our capabilities to deliver on time and modernizing our operations.”