Even though many drivers in Chicago tailgate on a daily basis, the law in Illinois strictly prohibits following another vehicle too closely. 625 ILCS 5/11 - 7/10 states that no driver should follow another vehicle “more closely than is reasonable and prudent.” The law requires drivers to take current traffic conditions into consideration, as well as the speed of the vehicles around them.
IDOT provides an additional tip on how drivers should judge whether they are following too closely or not, which is known as the “three-second rule.” You should stay at least three seconds behind the vehicle in front of you, which varies the distance depending on your speed. IDOT gives the following guidance:
25 miles per hour - 111 feet
35 miles per hour - 156 feet
45 miles per hour - 198 feet
55 miles per hour - 243 feet
65 miles per hour - 288 feet
70 miles per hour - 309 feet
While it is difficult to make an exact measurement while driving, all drivers should use their judgment when it comes to how close they are following another vehicle. Also, drivers should never use tailgating as a tactic to intimidate other drivers.