LED technology is cost-effective and energy-saving compared to other lighting options, but it may not always be the best choice for street lights. The cool, bright lights that have recently been installed in cities like Seattle and New York can be harmful to human health, a new statement from the American Medical Association argues. The group just released new policy suggestions on the subject, as Inhabitat reports.

"Despite the energy efficiency benefits, some LED lights are harmful when used as street lighting," Maya Babu, a neurosurgeon and AMA Board Member, says in a press release.

Most LEDs emit mostly blue light, which is problematic for several reasons. The high contrast of the light—which appears bright white—increases glare and can be uncomfortable for the eyes, making it a road hazard.

It’s also bad for people who want to get to bed at a decent hour. Blue light suppresses melatonin, making it hard for people to fall asleep. Doctors and sleep experts recommend that you turn off your electronics before bed for this reason, but you can’t exactly turn off the street lights in your whole neighborhood.

Bright city lights are harmful to animals and plants, too. Light pollution can encourage trees to bud earlier and disrupt the sleep cycles of birds.

The AMA estimates that about 10 percent of existing street lighting in the U.S. has been replaced with LEDs. The organization doesn't recommend staying away from LED street lights altogether, but recommends using lights that emit as little blue light as possible, reducing glare. They also suggest that street lights could be dimmed during off-peak hours. Bulbs should also be shielded so that the light shines where it’s supposed to, rather than into the bedrooms of neighbors or up into the sky.

There’s a reason we call bedtime "lights out."

[h/t Inhabitat]