Let’s put Amazon’s order for 100,000 electric delivery vans by 2030 into perspective. Today, FedEx uses 85,000 “motorized vehicles” to deliver packages around the world. UPS has around 123,000 package cars, vans, tractors, and motorcycles, including about 10,000 the company says use “alternative fuel and advanced technology.” One hundred thousand delivery vans? That’s a lot.

For proponents of electric vehicles, it’s a big opportunity—and not just for Rivian, the decade-old startup in which Amazon has invested, and from which it will buy the vans. Rivian, which has not yet put a vehicle into production, has a busy few years ahead of it.

More significantly, though, the deal suggests that fleets—delivery fleets, truck fleets, taxi fleets, ride-hail fleets—may be the key, or a least a key, to transportation’s electric future. That’s especially true in a country where just 2 percent of today’s auto sales end with someone driving a plug-in electric car off the lot.

Shifts in fleet purchases might show which way the wind is blowing. “Individual consumers are thinking through [electric vehicle purchases] as well, but they don’t have a forcing function,” says Bill Loewenthal, senior vice president of product at ChargePoint, which operates a network of EV charging stations.

Other organizations are inching toward big electric fleet buys. Transit agencies are getting more excited about electric buses, especially in Asia. London is pushing Uber to go all-electric. Even the US Postal Service may get in on the act, as it looks to award a multibillion-dollar contract for a new generation of mail delivery trucks. (The electric vehicle-maker Workhorse is reportedly a front-runner there.)

The scope of Amazon’s purchase will make its electric vans battery-powered tech ambassadors in many neighborhoods. “Hopefully exposure to technology, and people seeing electric trucks in their neighborhoods, will do a lot for the market,” says Jimmy O’Dea, a senior vehicles analyst with the Union of Concerned Scientists.

But the impact of all-electric fleets could be even greater. Big organizations using electric vehicles—like transit agencies with electric buses, or delivery companies with electric vans, or even autonomous vehicle companies like Cruise—often don’t allow the public to use their charging facilities. (Cruise charges its testing Chevrolet Bolts in a San Francisco garage basement.) But some do, says Loewenthal. “Depending on the day, during the daytime a charger might be available to the public, and at night that infrastructure will be used for fleets.” Charging stations cost thousands to install, so the support of big companies using electric vehicles in their fleets could make it easier for regular folks to top up.

Of course, this depends on where the vehicles will show up. If the electric vans appear only in cities like San Francisco or Oslo, where spot-the-Tesla games are already lively, their ability to expose new people to a new tech will be limited. Dubuque or Peoria, though, might be another story. Rena Lunak, a spokesperson for Amazon, declined to answer questions about where the company would use the delivery trucks.

The fleet purchase also sets a high-water mark for corporate fleet greening. One hundred thousand vehicles is, again, a lot, and other companies hoping to keep up with Jeff Bezos will have their work cut out for them. “Now everything is going to be measured against Amazon’s announcement, and I think that’s good,” says Camron Gorguinpour, a senior manager of electric vehicle work at the World Resources Institute. The purchase might also broaden lawmakers’ and policymakers’ ideas about what’s possible: If Amazon believes it can electrify a huge slice of its fleet quickly, why not push others to do the same?