Use caution if you drive in extreme heat

By Todd Sperry, CNNUpdated 6th July 2012
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The blistering heat wave blanketing much of the country isn't just unhealthy for people and pets, it can be catastrophic for roads and vehicles.
With temperatures expected to be near the 100-degree mark and extreme heat advisories in at least 15 states, officials are warning drivers to take precautions before heading out.
"Take water with you on your trip," said Jeff Cranson of the Michigan Department of Transportation, warning drivers to make preparations in case of an emergency that could force them to walk a significant distance in the extreme heat if their car breaks down.
Geoff Sundstrom of the Delaware Department of Transportation recommended that drivers have their car batteries tested if they are more than three years old.
"Heat is the number one killer of batteries, not the cold," Sundstrom said.
Meanwhile, the sweltering temperatures from Wisconsin to the Atlantic seaboard have forced state and local road crews into action repairing streets and roadways buckling under the intense heat. Pavement expands in the heat, and cannot contract if it does not cool down enough overnight.
Earlier this week, a viral video showed an SUV airborne after hitting a patch of buckled highway in Wisconsin.
Wisconsin received "upwards of 30 reports" of roads buckling Thursday, according to Don Miller of the Wisconsin Department of Transportation. He warned drivers to "stay alert and be on the look out" for damaged patches of road.
Illinois drivers also reported more than two dozen instances of warped roads in the last two weeks.
And drivers in Missouri were warned to be on the lookout for pavement buckling, or "blow-ups" as they're called in DOT jargon.
A blow-up occurs when a roadway surface expands at a crack or joint where moisture has seeped in. The crack weakens the pavement, and the heat causes the road to buckle and warp.
"Typically we see most of our road failures on secondary roads versus highways," said Guy Tridgell of the Illinois Department of Transportation. Water drainage is better on highways than side-streets, and highways are made to handle a substantially higher volume of traffic and are less susceptible to extreme temperatures, according to Tridgell.
Mark Giessinger of the Missouri Department of Transportation recommended that drivers who encounter buckled roads slow down and use caution before calling the appropriate DOT authorities in their state.
"Buckling is particularly dangerous for motorcyclists," said Greg Bilyeu of Virginia's DOT. "VDOT is working with the state materials engineer and the Virginia Transportation Research Council to analyze core samples and test pavement integrity to determine what can lead to buckling. ... These tests may help identify areas that are more susceptible to buckling in the future."
Michigan has only seen one significant buckle on a major road, on the west side of Detroit, according to Cranson.
In Pennsylvania, officials reported a few instances this week of roadway buckling at expansion joints where pavement connects to bridges. Dennis Buterbaugh of the state's transportation department said none of the incidents has been serious.
Buterbaugh urged motorists to take precaution when driving in excessive heat.
"This is the kind of weather where everyone needs to make sure that their car's tires are not under-inflated. Under-inflation causes a tire to run hot. Add that heat to the extreme air temperatures and it's a recipe for a blow-out. ... Check those tire pressures and keep them at the car maker's recommended pressures," he said.
Leaving the car at home and taking public transportation is no guarantee of avoiding heat-related problems. Extreme heat can also cause train rails to warp.
Metro system riders in the District of Columbia were warned Friday to "expect delays on all lines due to heat-related speed restrictions."