More than four years after the Des Moines Area Regional Transit Authority launched its electric bus pilot program, the transit agency has announced it is scrapping the program because of mechanical problems and safety concerns that kept the buses off the road.

DART acquired seven electric buses from Proterra and introduced them to the community in October 2020, with the buses going into service in January 2021.

Now it is disposing of the buses after the Federal Transit Administration granted a full waiver of the federal interest in the buses, which means DART will not have to pay back the federal government, which awarded the transit agency a $1.45 million Low or No Emission Grant in September 2017.

In an email to the Business Record, officials with DART said the pilot project showed the electric buses reduced energy costs and demonstrated environmental benefits. But the buses were taken out of service after 22 months because of expiring warranties, major mechanical failures, safety concerns and driver complaints. The buses were on the road only about 60% of the time, compared with an average 90% for non-electric buses, officials said.

“After repeated attempts to work with the manufacturer to address major issues with the buses that have gone unresolved, we determined it would be too costly to keep the vehicles in our fleet and we are grateful the FTA recognizes that as well by granting us a full waiver on the federal interest,” officials said in the email.

Proterra filed for Chapter 11 bankruptcy in August 2023.

The DART board of commissioners voted in March to begin the process of disposing of the buses.

According to board documents, DART received a report in October 2024 from another transit agency that discussed a structural flaw in the electric buses’ composite body.

DART shared the report with the FTA and in November 2024 was granted a waiver for the remaining life of the seven buses. DART would usually have to repay the FTA for the useful life of the buses if they were disposed of before their useful life expired, documents state.

Other transit agencies have also had to remove Proterra buses from service, officials said in the documents.

DART typically buys buses every year and it’s rare that a bus can’t meet its intended useful life, officials said.

The cost of an electric bus, purchased from Proterra, is $863,000, compared with $494,000 for a diesel bus.