CHICAGO (CBS) — Black ice caused a string of crashes overnight on the Ohio Feeder Ramp to the Kennedy Expressway.

A taxi cab was just one of several vehicles that crashed into the median, or into each other, due to invisible slick spots while trying to get to the Kennedy late Thursday night or early Friday.

The downtown area got some freezing drizzle and snowflakes overnight.

Drivers slowed down after seeing all the accidents, including at least one chain-reaction crash.

Illinois Department of Transportation trucks came out soon after the crashes and treated the roads.

No injuries were reported.