The Bossier City (La.) Police Department is adding 35 new police vehicles with compressed natural gas (CNG) conversions to its fleet for a cost of approximately $1.5 million.

The City Council approved the purchase, to be funded by the sales tax capital improvement fund, on August 5.

The city has been converting its fleet to alternative fuels for the last four years, since the first CNG fuel station opened in the city in 2010, according to KSLA. Its first CNG ambulance was unveiled in May, a purchase that was delayed because the city couldn't find a manufacturer to design and build it until recently.