A longstanding and frustrating tradition in this country for both automakers and automotive enthusiasts is that vehicles that are available in Europe aren’t always for sale here in the U.S.

We’re not just talking about hot car models like the Audi A1, but individual features that don’t pass muster with U.S. regulators for one reason or another -- even though they would clearly increase safety.

The latest example is Audi’s Matrix LED lighting, which the German automaker touted at the recent Consumer Electronics Show and said would be available here in the U.S. sometime in 2013. But, as with other features we can’t have here, federal regulators said, "Not so fast" just last week.

The LEDs used for the high beams in Audi’s Matrix headlights are subdivided into several different segments. These individual LEDs can be independently activated, deactivated or dimmed, and they work in conjunction with lenses or reflectors to adjust light according to environmental situations.

The high-tech headlights also receive input from an onboard camera. When the camera detects other vehicles, sections of the high-beam light can be blocked. They even receive input from the car's navigation system to know what's ahead and automatically swivel, for example, when the car approaches a curve.

But an Audi official told a group of technical experts and regulators at the recent Washington Auto Show that the Matrix headlights don’t fit rules set by the National Highway Traffic Safety Administration for high beams. Under the Federal Motor Vehicle Safety Standard 108, “headlights are not allowed to shine in such a dynamic way,” according to Automotive News. It also reported that Audi has asked NHTSA for an interpretation of the standard to determine how the Matrix headlights -- given that they’re designed to make driving safer -- can be allowed in the U.S.

This is just the latest example of how differing vehicle standards in the U.S. and Europe can block safety innovations from coming to this country -- and cause drivers here to miss out on technology that could help reduce accidents. Automatic hazard lights that activate in an emergency braking situation to warn following drivers are common in Europe, for example, but haven’t been allowed here. And a recent advancement in night-vision technology that BMW calls Dynamic Light Spot, which that shines a highly focused beam to warn the driver of pedestrians and animals, has been blocked in the U.S. because of government regulations.

Automotive News said that regulators may eventually allow Audi’s Matrix headlights to be available on cars in the U.S. once they deem them safe. But until the feds interpret rules to allow the headlights to be available here, U.S. drivers will have to be satisfied with a less sophisticated feature, automatic high beams, which simply use a camera to switch the high beams on and off for oncoming cars.

When Audi eventually switches to lasers, it may take much longer for U.S. regulators to make a decision. Automotive News reports BMW is also developing lasers to “offer a distinctive look.” But before laser headlights or taillights are ready for the road, automakers and government officials will need to decide whether a laser diode counts as a "light emitting diode" for regulatory purposes, an Audi representative told Automotive News.

Whatever happens, you can bet we won’t get it first.

Doug Newcomb has been covering car technology for more than 20 years for outlets ranging from Rolling Stone to Edmunds.com. In 2008, he published his first book, "Car Audio for Dummies" (Wiley). He lives and drives in Hood River, Ore., with his wife and two kids, who share his passion for cars and car technology, especially driving and listening to music.