The major cell-phone carriers have a new ally in their fight against stricter net-neutrality regulations: General Motors.

The car company sent a letter to the Federal Communications Commission earlier this month urging the agency not to impose tough rules on wireless Internet service. Treating wireless Internet the same as a home connection would stifle innovative new technologies, General Motors wrote.

"From our point of view, mobile broadband being delivered to a car moving 75 mph down a highway—or for that matter, stuck in a massive spontaneous traffic jam—is a fundamentally different phenomenon from a wired broadband connection to a consumer's home," wrote Harry Lightsey, the executive director of GM's Global Connected Consumer unit.

He said that car companies are increasingly relying on wireless networks to provide new technologies to their customers. High-speed cellular connections allow people to stream Internet radio and video in their cars, and some cars even have built-in Wi-Fi hotspots.

Companies are also starting to experiment with technologies that would allow cars to talk to each other to avoid collisions and monitor traffic patterns. Those technologies all rely on some form of wireless connection.

"By needlessly constraining the latitude our mobile network operator suppliers have in delivering connectivity to owners of our vehicles, you would also constrain the innovations we are seeking to provide to our customers," Lightsey wrote.

Net neutrality is the principle that Internet providers shouldn't be allowed to manipulate traffic or favor some services over others.

The FCC first enacted net-neutrality rules in 2010 that focused on home Internet service and largely exempted cellular connections. A federal court struck down those rules earlier this year, and FCC Chairman Tom Wheeler is now trying to craft new regulations that can survive future court challenges.

Wheeler has strongly hinted that he may scrap the distinction between wireless and fixed Internet, noting that an increasing number of people rely on their phones to access the Internet.

Verizon, AT&T, and the other cellular carriers argue that wireless Internet is different because it's difficult to transmit data over-the-air. They want more flexibility to prioritize some services, especially if a cell tower is congested.

Michael Weinberg, a vice president at the consumer advocacy group Public Knowledge, said net-neutrality rules aren't meant to cover specialized data services that don't connect to the broader Internet. Some car technologies do rely on regular cellular connections to access the Internet, but he said any problems could be handled by an exemption for "reasonable network management."

"There should still be overarching rules that protect people who want to access the Internet no matter how they want to do it," he said.

The key, Weinberg said, is that companies should be allowed to prioritize some traffic if it's for engineering reasons—not if they're just trying to make some extra money.