Purdue’s second annual study of traffic flow on Indiana’s interstates adds a new calculation: how much time is lost to traffic jams.
Joint Transportation Research Program Director Darcy Bullock explains the old measurement of congestion simply counts how often traffic was moving slower than 45 miles an hour.
By that definition, the most congested stretch of interstate was I-74 on Indianapolis’ southeast side. A half-mile of highway just before crossing outside the I-465 loop was moving well below posted speeds nearly half the time in 2012.
But “congestion” makes no distinction between traffic moving at 44 miles an hour and traffic at a dead stop. On most of the highway segments rated as the most congested, drivers lost only a few minutes.
People lost nine times as much time to a 14-mile construction zone on I-70 between Clay County and Putnamville.
The only areas near the top of both measurements are the Kennedy Bridge on I-65 crossing into Kentucky, and northbound I-69 between 96th and 116th Streets. The already-clogged Kennedy Bridge got even slower in the first part of 2012 as the closure of the Sherman Minton Bridge diverted southbound traffic there.
Eastbound 465 approaching Allisonville Road on Indianapolis’ north side averaged 86 minutes a day of congestion. The stretch just before that, as drivers pass Keystone Avenue, ranked among the most time-consuming.
Southbound 69, from 96th to 82nd Street, was jammed almost as often, but drivers lost 25 times as much time on the northbound route.
Slow traffic was also common on I-65 downtown between Illinois and West Streets, with traffic running below speed an average of 89 minutes every day. But drivers did not sacrifice much time there.
On the other hand, delays on westbound I-70 approaching Mount Comfort Road, on I-65 in both directions approaching Lebanon, and on I-69 from Lapel north to Anderson and from Noblesville south to Fishers were costly when they occurred.
Bullock says the study helps INDOT plan ahead for future construction delays.