The New York City government has made another bold proclamation in favor of electric cars.

Mayor Bill de Blasio issued an executive order calling for all vehicles in the municipal fleet to be fully electric by 2040. That includes not only cars, but everything from ambulances and police cruisers to garbage trucks and ferries, according to a press release issued by the mayor's office.

The electrification of New York's municipal fleet will begin ramping up soon. The first electric school buses will hit city streets this year, and 4,000 vehicles will be either replaced by electric models or converted to electric power by 2025, according to the mayor's office.

The executive order appears to build on a 2015 proposal by de Blasio to deploy 2,000 electric cars in the municipal fleet by 2025. Those vehicles were intended to be used in non-emergency roles by agencies such as the Parks and Recreation Department.

At the time, officials said the program could cut government-vehicle emissions 50 percent by 2025, and expected fuel savings to offset much of the cost of getting the electric fleet operational.

New York City has also proposed electrifying another large fleet of vehicles operating on its streets: taxis. Nissan Leaf taxis were given to a handful of New York cabbies for demonstrations, and in 2014 a task force laid out recommendations for electrifying one third of the taxi fleet by 2020.

That didn't happen, however, showing the limitations of electric car technology, charging infrastructure, and of cab drivers' patience for decrees from City Hall.

The failed implementation of the Nissan NV200 as New York's "Taxi of Tomorrow" shows that taxi operators can't be easily corralled into using one type of vehicle [well, except for Checker Marathons or Ford Crown Victorias, perhaps]. Although even the efforts the city has made so far to raise mpg have cut pollution, according to a recent study.

But a plan to electrify municipal vehicles doesn't rely on the whims of individual operators. The city government can simply decide to replace certain vehicles with electric alternatives all at once.

The executive order came shortly after the United Kingdom government announced that it would move to ban sales of new gasoline and diesel cars by 2035. Reports have indicated that plug-in hybrids will be banned as well. These announcements show that governments are getting serious about cutting transportation-related emissions.