The main roads are in good shape but some side streets still have black ice on them.

Gridlock Guy: Two-hour delayed openings for ice caused more problems than the ice

Tuesday was a bizarre episode in Atlanta traffic. As Atlantans braced themselves for potentially widespread black ice, many businesses, schools, and government offices delayed the starts of their days by two hours. This meant their days started at 9:30 or 10 a.m., instead of at 7:30 or 8. But morning rush hour still could have been a bear, as temperatures following three days of rain were expected to dip into the low 30s and freeze the remaining moisture on the ground. That didn’t happen.

» RELATED: Black ice: What Georgia drivers need to know to stay safe

Save for a few icy patches in the far northern suburbs and the mountains, ice was not a problem for the commute. The temperatures largely stayed above freezing and the roads began drying out as the morning progressed. Since the various entities had committed to delaying their openings, commuters that had to venture out earlier Tuesday morning got a real treat.

“As one would expect, the “normal” rush period of 7-9 a.m. saw a significant reduction in traffic volume — to the tune of 40% in most areas, as drivers stayed home because of their delayed start,” GDOT assistant state engineer Mark Demidovich explained. “As a result, traffic congestion was almost nil during those hours. Normally congested freeways kept flowing at around 55 mph.”

But as motorists breezed through the morning drive, chaos began breaking loose in the 8 a.m. hour. This unrest may have had nothing to do the change in traffic schedule, but increased speeds mean that vehicles hit harder. During this hour, a string of wrecks broke out against the normal rush hour direction, two of which involved tractor trailers and shut down I-20/westbound near Riverside Parkway (exit 46) in Cobb County.

As those delays built while traffic was light elsewhere, the commute went to the hounds in the 9 a.m. hour. “However, after 9 a.m., as drivers began heading towards their 10 a.m. starts for work and school, the traffic volume sharply increased — right back to the levels we would normally see at 7 a.m,” Demidovich said. Where the traffic volume was 40% lighter than normal before 8 a.m., it was that much worse from 9-10. And the unusual delays continued past that 10 a.m. start time.

“The rush hour began at 9 a.m. and lasted until almost noon,” Triple Team Traffic midday co-anchor Veronica Harrell explained. “The volume on the roads mixed in with daily construction made for a disastrous Tuesday.”

Indeed. In addition to just the late push of rush hour traffic, some gnarly wrecks paralyzed the ride in several areas. Tractor trailer crashes shut down parts of I-75/northbound in Henry County both at Locust Grove (exit 212) and Hudson Bridge Road (exit 224) in the mid-morning.

» RELATED: Tractor-trailer fire closes I-285 lanes for several hours 

Then, simultaneously, a tractor trailer caught fire and, at one point, shut down I-285 in both directions near Hollowell Parkway (exit 12) and left southbound blocked for quite a while. Then a big rig crash took out two left lanes of I-285/northbound at Martin Luther King Junior Drive (exit 9).

And not to be outdone, another wreck on the south side briefly shut down I-75/northbound at I-285 (exit 238). Then a tractor trailer tipped over and blocked the sharply curved I-285/eastbound ramp to I-75/southbound (exit 58) for a couple of hours. Like the others, both of these wrecks caused big-time delays.

Something about a change in environment or conditions often causes a spike in wrecks. The changes in speeds during the 9 a.m. hour might have contributed to these nasty crashes all over town. Also, morning rush hour usually starts slow and rises to a gradual boil. But Tuesday’s ride was steady and then the volume just poured into the mix all at once. That sharp spike in traffic — the sudden backups — could have caught people by surprise and contributed to this rash of crashes.

The WSB Traffic Team had no reports of crashes because of the ice, and the delayed start times drastically improved the traditional morning drive. Ironically, that change pushed the rush hour forward and certainly seemed to cause more trouble than the ice did. Georgians made the right move in taking extreme precautions, no doubt. But Harrell may have put it best. “The two-hour delay is great for sleeping in, but not good for Atlanta traffic.” 

» RELATED: What is black ice and how does it form?

Doug Turnbull, the PM drive Skycopter anchor for Triple Team Traffic on News 95-5 FM and AM-750 WSB, is the Gridlock Guy. He also writes a traffic blog and hosts a podcast with Smilin’ Mark McKay on wsbradio.com. Contact him at Doug.Turnbull@coxinc.com.

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