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Originally published October 24, 2012 at 5:44 PM | Page modified October 25, 2012 at 10:05 AM

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Texas takes it to the limit: 85 mph

Texas on Wednesday opened a toll road with the nation's fastest speed limit — 85 mph — but some worry that's too fast.

Cox Newspapers

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AUSTIN, Texas —

How fast is too fast?

On Wednesday, workers removed barricades at entrances and exits on the new 41-mile-long section of the Texas 130 tollway south of Austin, and drivers began doing something they've never done legally in Texas: go 85 mph.

The Legislature, based on a law it passed last year, thought driving that speed — a higher limit than on any other road in America — will be safe, or at least sufficiently safe to justify the time savings and other economic benefits it could bring to drivers and the state. That includes a $100 million payment to the Texas Department of Transportation (tied to the higher speed limit) from the company that built the tollway, will operate it and will pocket the toll revenue for the next 50 years.

TxDOT officials say 85 mph is safe given the design of the four-lane, divided expressway, or at least no less safe than if the limit were 5 or 10 mph lower. And they say the higher limit doesn't necessarily mean that many drivers, adopting a strategy common at lower speed limits, will simply add a cushion unlikely to earn them a speeding ticket and drive about 90 mph. The overwhelming majority will drive speeds that are prudent, TxDOT maintains.

But some traffic-safety experts say that when a speed limit is increased, drivers typically go faster; that when speeds increase there are more accidents; and that more people die in those accidents because of the greater forces involved.

"We have decades of study and data, and conclusive evidence, that people do respond to speed limits no matter how high they're set," said Richard Retting, a widely published traffic-safety expert and vice president of the New York-based engineering firm Sam Schwartz Inc. "We just have to learn that there is no free lunch when it comes to high speed limits. And the price we pay is higher speeds and a higher fatality rate."

Rising limits

Speed limits across the country have been on a steady climb since 1987, when Congress eased the nationwide 55-mph speed limit imposed in 1974 after an Arab oil embargo caused gasoline shortages and rising prices.

That move also came as environmental consciousness was on an upswing, and the lower limit was seen as a way to reduce tailpipe emissions and the resultant air pollution.

Automobiles generally get the best gas mileage at about 55 mph, experts say, and the fuel efficiency steadily decreases as speeds go up.

After allowing 65-mph limits on rural interstates in 1987, Congress in 1995 once again put speed-limit authority completely in state hands. Many states, including Texas, responded by raising most interstate limits to 70 mph. In 2002, Texas began setting 75-mph limits on some highways in sparsely populated counties. In 2006, TxDOT raised the limit on sections of Interstates 10 and 20 in West Texas to 80 mph.

Since the Legislature last year broadened TxDOT's authority to set 75-mph limits and higher, the Texas Transportation Commission has been increasing limits almost monthly. There are now almost 7,000 miles of Texas roads with a 75-mph limit and 575 miles where it is legal to go 80 mph. That's almost 10 percent of the state highway system.

Carol Rawson, director of TxDOT's traffic-operations division, said data from those two West Texas interstates, as well as two Austin-area tollways that for several months have had 80-mph speed limits, buttress the idea that speeds and fatality rates on Texas 130 will not necessarily skyrocket.

In the three-year period before the 80-mph limit went into effect on I-10 and I-20, that 520 miles of highway saw 103 traffic fatalities, or about 34 deaths per year. In the next six years, there have been 146 deaths, or 24 per year. That's a decrease, on an annual basis, of about 29 percent.

"It says to me the speed didn't impact the numbers," Rawson said. "I think the 85 (on Texas 130) is safe and prudent."

On the existing 49 miles of Texas 130, also a tollway, which opened between 2006 and 2008 with a 70-mph speed limit, TxDOT first increased the limit to 75 mph and then, in April, to 80 mph. At the same time, the agency increased the limit to 80 mph on Texas 45 Southeast, another tollway that connects Interstate 35 to Texas 130 near Mustang Ridge. Rawson said there have been no deaths on either road since the change.

Other safety factors

But Retting said Rawson's simple comparison on I-10 and I-20 ignores other factors that have driven down traffic fatalities statewide and across the country, including greater use of seat belts, safety improvements in vehicles such as added air bags, and the economic downturn, which led to less driving. The more relevant comparison, he said, is traffic deaths per million miles driven, not per year. Rawson could not provide those statistics for the 85-mph sections of I-10 and I-20.

Traffic deaths in Texas fell from 3,822 in 2003 to 3,015 last year, a 21 percent drop. Nationwide, traffic deaths fell 28 percent in that period, comparable to the decline on the two interstates with the 80-mph limit.

"We don't know what the fatality rate would have been (on I-10 and I-20) without the increased speed limits," Retting said.

Retting, who was with the Insurance Institute for Highway Safety at the time, studied speeds on those roads after TxDOT increased the limit from 75 to 80 mph. According to his 2008 analysis in the Journal of Safety Research, I-20 saw a 9-mph increase in average speed, and I-10 had a 4-mph average increase. The portion of vehicles going over 80 mph increased from 1 percent to 10 percent on I-20 and from 4 percent to 7 percent on I-10.

"What concerns us most is the percentage of drivers who are driving at very high speed," Retting said. The vehicle safety improvements and the decreasing highway deaths in recent years may have created a false sense of the relationship between safety and speed, he said.

"We don't want to lose that momentum and the benefit by raising limits," Retting said.

In 2005, Norwegian Rune Elvik, chief research officer for the Institute of Transport Economics at the University of Oslo, did a so-called meta-analysis of 98 studies, conducted over almost 40 years, of the nexus between road speed and traffic fatalities. His conclusion: "Speed has a major impact on the number of accidents and the severity of injuries," and "the relationship between speed and road safety is causal, not just statistical."

Troopers, tolls

When TxDOT opened the northern section of Texas 130 and two connecting toll roads, it paid the Texas Department of Public Safety to dedicate extra troopers to the road. That contract ended in 2011, and neither TxDOT nor the SH 130 Concession Co., the new section's operator, has arranged for added enforcement.

The new stretch of Texas 130, despite the higher speed limit, will get the same level of enforcement as any other road in the state highway system, officials said. In an opening promotion meant to allow potential customers to familiarize themselves with the road, it will be free to drive until Nov. 11. After that, tolls will be about 15 cents a mile for cars and other two-axle vehicles. Larger trucks will pay multiples of that, based on the number of axles.

Rawson said the experience with the state's 80-mph roads indicates that these higher legal thresholds may be close to that indefinable prudent limit and won't be widely flouted.

"We haven't seen it with the 80s," Rawson said. "But the 85 is a brand new one. It's certainly something we'll keep an eye on."

Ben Wear writes for the Austin American-Statesman.

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