Parker said drivers who find ice patches should call 311 to report it.
The top priority in Galveston was keeping the causeway open. TxDOT treated the bridge with magnesium chloride to keep it ice-free in temperatures below 20 degrees. By 8 a.m. Friday, traffic was reduced to one lane each way because of icy conditions.
The Texas Department of Transportation and Harris County Toll Road Authority treated bridges and overpasses with magnesium chloride before the freezing rain arrived, but it was not enough.
"The Toll Road Authority did everything they could, but this is the kind of incident you just cannot control," Emmett said.
Emmett said the precautions taken worked as well as they could.
"The worst scenario is always to have freezing rain," he said. "Not sleet, not snow, but rain that falls and freezes once it hits the ground. When that happened, roughly around midnight, then the trucks couldn't even go put down other chemicals. The HCTRA trucks, the TxDOT trucks, they couldn't get up to put any more chemical down. That's why the whole system shut down."
Emmett said that if the ice melts enough, trucks will be sent out to treat the roads before it freezes again late Friday and early Saturday.
"Even though it melts, and even though it gets treated, if it re-freezes, we're going to be in the same circumstance," Emmett said.
TxDOT said crews have been working around the clock to monitor the roadways. Officials said they expected snow, but what Mother Nature delivered was much worse.
A TxDOT sand truck lost control on an icy road in Katy and flipped on its side.
"It's a little more challenging for us, actually a great deal more challenging for us than the anticipated snowfall that was initially forecasted," said Raquelle Lewis with TxDOT.
TxDOT said 140 people, 65 sanding trucks, 70 herbicide/shadow vehicles and 15,000 gallons of liquid magnesium chloride were used to monitor and combat the icing conditions.
"I'm confident that our efforts in treating the roadways with the magnesium chloride helped to minimize the severity of this event. Without our pre-treatment activities, the event could have been much worse," said Houston district engineer Delvin Dennis, with TxDOT.
METRO Park and Ride service was canceled Friday. All high-occupancy vehicle lanes have been closed. METRORail service was modified to 10-minute intervals between trains instead of the normal 6-minute intervals. Bus service was expected to operate on its regular schedule, but some detours because of ice may be necessary.
The wintry conditions also make travel by water troublesome. The Lynchburg Ferry closed at 2 p.m. Thursday. It will not reopen until 10 a.m. Saturday.