So you think 70 mph is safe for driving? Think again.

The dangerous consequences of changing the state's top speed limit from 65 to 70.

WHEN WISCONSIN RAISED the speed limit on many of its freeways to 70 mph in 2015, some worried the roads would become more dangerous. Here, in the last state in the Upper Midwest to adopt a 70 mph maximum, supporters painted critics as alarmist. How dangerous could 70 be, they asked, considering how many people drive that fast anyway?

Now the numbers are in, and some freeways in Southeastern Wisconsin have gotten safer – those where the limit wasn't raised. For freeways bumped up to 70 (the majority), the total number of crashes increased, along with those resulting in injury or death.

On the faster roads, crashes rose 1.5 percent, and those with injuries jumped 16 percent. Interestingly, overall wrecks dropped 16 percent on their sub-70 counterparts, and ones with injuries slid 31 percent.

Mike Pyritz, a spokesman for the Wisconsin Department of Transportation, said the above wasn't enough data to draw conclusions. Both he and Shelia Dunn Joneleit, spokeswoman for the National Motorists Association, say other factors besides speed – such as weather, substance abuse and seat belt trends – could account for differences in crash totals.

An increase in the speed limit typically results in an increase in traffic deaths, according to Jessica Cicchino, vice president for research at the Insurance Institute for Highway Safety. “For every 5 mph that states [have] raised their speed limits, the number of fatalities went up 8 percent on interstates and 4 percent on other roads.”

Fatal crashes rose and fell on Southeastern Wisconsin's faster roads, from eight to 11 to nine over the past two fiscal years. In contrast, crashes causing deaths on the slower freeways slid from 10 to seven to four. Cicchino's institute claims that higher speed limits have wiped out “most of the progress” from airbags, which saved about 40,000 lives between 1993 and

2013, according to government numbers. At the same time, the institute says higher speed limits resulted in 33,000 more fatalities.

Zooming, 70-plus speed limits were common before 1974, when Congress set a nationwide 55 mph limit in response to a Middle Eastern oil embargo and gas shortage. In 1987, Congress relaxed the law to allow 65-mph limits on rural interstates, then repealed all national speed limits in 1995. Though many urban freeways (including in Milwaukee) remain at 50 or 55 mph, rural freeways now range from 60 mph in Hawaii to 85 mph in Texas.

Starting in June 2015, the DOT began posting 70 mph limits on

147 of the 230 freeway miles in southeastern Wisconsin, almost all of them outside Milwaukee County. Another 14-mile zone in Waukesha County is scheduled to make the jump later this year, after upgrades are made to Highway 16.

Nine states, including Wisconsin, have raised their speed limits since 2015. “It has been really frustrating,” Cicchino says.

Ordinarily, state crash statistics are grouped together by road type, rather than speed limit. To get a better picture of the 2015 law's effects, Milwaukee Magazine requested separate figures for the 70-mph freeways and those with lower limits and compared the 12 months before the limit rose with the 24 months that followed.

Joneleit's Waunakee-based association, founded to fight the original 55-mph limit and push it higher, argues that higher speed limits reflect how people actually drive, also a major argument of Wisconsin legislators who voted in favor of the 70-mph limit. But Cicchino says her institute's research shows that people who exceed lower speed limits will also break higher ones if given the chance. “People like to go faster,” she says.