Densely populated cities should consider switching to all-electric truck and bus fleets, elected officials and business leaders agreed this week at the Global Climate Action Summit in San Francisco.

The political and manufacturing leaders joined in the "Global Commercial Vehicle Drive to Zero" pledge to focus on electrifying commonly used commercial vehicles including city buses, and heavy and light-duty trucks.

The pledge aims to make electric trucks and buses commercially successful by 2025 and widely used by 2040 in the targeted areas. 

READ THIS: One third of new transit buses will be electric in 2020, all by 2030: Proterra CEO

Transportation consultant Calstart is coordinating the pledge and providing data on where efforts should be focused.

New York and Los Angeles have agreed to move to all-electric city bus fleets, along with regional transit authorities including Foothill Transit, which operates between San Bernadino and L.A. The pledges from New York and L.A. also include municipal truck fleets.

The mayors of Sacramento and Stockton, California, and Oslo, Norway, also have agreed to potentially convert all of their municipal truck fleets to electricity.

DON'T MISS: These 12 cities will buy only electric buses from 2025 on; more expected to join

Manufacturers who signed on to support the pledge include electric bus makers BYD, Proterra, and New Flyer; Mitsubishi-Fuso, which builds electric, hybrid, and conventional trucks; and truck-rental company Ryder.

The pact also includes Workhorse, Motiv Power, and Zenith, which build electric, plug-in hybrid, and fuel-cell conversions of conventional trucks and vans, along with many companies that build electric-vehicle components.

CHECK OUT: LA gets first double-decker electric city bus

“By working across national and state boundaries, through this new focused effort, we can accelerate progress and help bring these important clean technologies to market years earlier,” Richard Corey, executive officer of the California Air Resources Board, said in a statement.

"By showing the demand for these vehicles, and focusing on the most viable markets, we can accelerate their adoption, improve air quality and reduce emissions,” John Boesel, president and CEO of Calstart, said in a statement.

“Once we achieve commercial viability in these areas, we can work to reach economies of scale, bring costs down and increase adoption throughout the entire medium- and heavy-duty vehicle industry,” he added.