Cars are America. America is freedom. It's no accident that the country's foundational myths are written in road trips. The Oregon Trail. Sal Paradise and his Cadillac. That time your stoner college roommate decided to drive his crap can from Jersey to LA.

And freedom is getting faster, at least in the West. In April 2015, South Dakota became the fifth state in three years to increase its daytime interstate speed limit to 80 miles per hour or more. On some sections of Texas road, 85 is de rigueur.

The economic and emotional justifications for the trend were neatly laid out by The Idaho Statesman editorial editor Robert Ehlert: “The 80 mph speed limit is an antidote to those high airline ticket prices and nickel-and-dime onboard fees,” he wrote. (Given today's crazy low gas prices—$2.31 in Idaho right now—he's not wrong about airline tickets, especially if he's checking a bag.) “The 80 mph speed limit is symbolic of my individuality and freedom ... This is the West. This is the way we roll.”

But a raft of research shows that when speed limits go up, so do fatalities—along with financial costs and environmental hazards. A 2009 study published in the American Journal of Public Health estimates speed limit increases were responsible for 12,545 deaths and 36,583 injuries between 1995 and 2005. The number of rural interstate fatalities we can blame on higher speed limits jumped 9.1 percent during that time.

Why, then, have speed limits—and especially speed limits in rural areas—rocketed in recent years? Partly, it's that speeding exists in a cultural gray area. Everybody does it, so why not change the rules to reflect that? More crucially, it's a result of regional politics, where geography, ideology, and antipathy for regulation make higher limits a win.

Freedom Vs. Danger

According to AAA, nearly half of all drivers say they drive 15 mph over the speed limit "regularly." More than a quarter of all drivers admitted in a NHTSA survey that "speeding is something I do without thinking." 16 percent believe "driving over the speed limit is not dangerous for skilled drivers."

Fatal crashes have dropped 20 percent since 1999, but more than 30,000 people still die on US roads every year. Speeding plays a role in nearly a third of those crashes, NHTSA says, but the agency has focused its safety efforts on drunk and distracted driving.

"Unlike other things like drunk driving and seat belts, speeding is a continuum,” says Kara Macek, the communications director at the Governors Highway Safety Association, a membership organization of state highway safety associations. In other words, the wrongness of speeding is far less clear cut than the problems with texting while driving, or drinking before getting behind the wheel.

This flexible attitude toward speeding lets lawmakers argue that low speed limits make criminals out of everyday motorists. The problem is that some people will never go 80 miles per hour, says Iowa State University civil and environmental engineer Peter Savolainen. And crashes are more likely when vehicles are traveling at very different speeds. Higher maximums mean wider gaps in speed between individual cars. That's less safe for everyone. A recent analysis led by Wayne State civil engineers found that fatality rates on roads with limits of 75 mph or higher are double those on interstates where things move more slowly.

Economic Costs

Higher speed limits come with a financial cost, too. Changing the rules doesn't just mean repainting the signs. State DOTs have to revamp the infrastructure, making road curves smoother and adding crash pads to medians, for example, to make driving faster safer. Faster driving means maintenance costs go up, too. In 2014, researchers working with Michigan’s DOT found that upping rural interstate speed limits from 70 to 80 mph would save 15.4 million passenger vehicle hours a year, but would also cost $163.88 million annually for the design's estimated 25-year lifespan.

And of course, driving faster burn more fuel. That's why Congress set the national speed limit at 55 mph in 1978. (It nixed the law in 1995, and returned the power to set limits to the states.) That same Michigan DOT report estimated raising freeway speeds would increase the state’s annual fuel consumption by 68.7 million gallons—about $257.5 million worth of the good stuff (at 2012 prices). And if the money part doesn't get you, remember that 68.7 million gallons of gas is equal to 1.3 billion pounds of CO2 emissions.

None of that counts the economic and societal costs of crashes themselves—$836 billion in 2010, according to the feds.

Raise 'Em Anyway

Western states are upping their limits anyway. Geography plays a role: Driving faster makes getting around rural areas more practical.

Regional politics matter, too. It's no secret the states in questions are Republican territory (though a pair of researchers in Barcelona did a study to make sure). Upping the speed limit "sounds like such an easy regulatory win," says Owen Gutfreund, a transportation historian at Hunter College. It's a simple way to "get government out of your face," , and "the consequences are remote and don’t come back to cause any problems."

You can present all the traffic fatality data you want to the politicians voting on speed limit laws, Gutfreund says. But unless a speeding-related crash "has happened to them or someone close to them, it’s just a set of numbers on the page."

Experimenting with a higher speed limit has gone well for at least one western state. According to a spokesman for the South Dakota Highway Patrol, the state hasn't seen a significant increase in road deaths since it implemented its new 80 mph speed limit in April 2015. Law enforcement is focusing on preventing impaired and distracted driving and enforcing seatbelt laws.