The ubiquity of distracted drivers should alarm every Chicagoan. They’re roadway menaces, and we know how to spot them.

Stopped at a red light, the distracted driver is seen from behind gazing downward and to the right. The light turns green, but the distracted driver’s car doesn’t move, not until the motorist behind taps his horn. In traffic, the distracted driver is given away by slow swerves across the lane lines, as his or her head darts from cellphone to windshield, cellphone to windshield. At night, like hyena eyes that glow in the dark, the distracted driver’s presence is obvious — suffused in the device’s glow, head darting from cellphone to windshield and back.

By no means an endangered species, the distracted driver teems in every neighborhood, every suburb. And if there’s a crash in your neighborhood or suburb, there’s a decent chance that it involved distracted driving.

A study released by Cambridge Mobile Telematics found that nearly 1 of every 4 drivers involved in a crash was using a cellphone within a minute before the accident, the Tribune’s Mary Wisniewski reports. The study also found that distracted driving occurred in more than half of car trips that ended in a crash.