As speedometer needles inched farther right following the switch to 70 mph speed limits in Wisconsin last year, fatalities, injuries and accidents spiked.

Since distracted and impaired driving as well as speed are frequently the causes of accidents, it's not clear that the higher speed limit is the reason behind the increase. The number of miles driven has gone up as the economy continues to rebound, gas prices are low, and the number of 16-year-olds eligible for driver's licenses has increased while older drivers are staying on the road longer, according to census statistics.

In the 12 months following Wisconsin’s switch to 70 mph on interstate highways starting in June 2015, fatalities rose 37 percent on the interstate, injuries increased by 11 percent and the total number of accidents rose 12 percent. In that time 10 more people died, 208 more were injured and 1,057 more accidents were reported than the previous 12 months on interstate roads.

On U.S. and state highways in Wisconsin, which included a small portion of roads where speed limits were boosted from 65 to 70 mph but otherwise the speed limit remained unchanged, fatalities dropped by just under 2 percent, accidents with injuries declined by 0.2 percent and all accidents dipped 2 percent. Of the almost 11,000 miles of state highways in Wisconsin, 161 miles are now 70 mph.

On Wisconsin’s county highways, fatalities, injury accidents and total accidents rose but by much less margins than on the interstate - fatalities increased 14 percent, injuries went up by 5 percent and the total number of accidents increased by 1 percent.

Road crews began installing 70 mph speed limit signs in mid-June 2015, though it took a few months for all of the state's interstate highways to get the higher speed limit. Wisconsin was the last state in the upper Midwest to change to 70 mph, joining 38 other states whose maximum speed is 70 mph or higher.

Not all portions of interstate are posted at 70 mph - in municipalities such as Milwaukee and Madison, speed limits remain lower. And a small number of U.S. and state highways switched to the higher speed limit last fall including 22 miles of U.S. 151 in Dane and Columbia counties, 13 miles of U.S. 45 in Washington County and 10 miles in Brown County on State Highways 29 and 57.

While drivers texting, talking on phones, sending emails and fiddling with radios continue to cause many accidents, Nick Jarmusz of AAA Wisconsin points out that legally traveling 5 mph faster - and, of course, drivers are often lead-footing it quicker than that - means much less time to respond to changes in traffic, such as backups. When crashes occur, the physics of a body traveling at a higher speed crashing into another object frequently results in serious injury or death.

"Crash forces increase exponentially. The difference between a 65 mph and 70 mph crash may not seem like a lot but it's much more of an impact," said Jarmusz, director of public affairs for AAA Wisconsin, which opposed the 70 mph bill in the state Legislature.

So far law enforcement leaders in Wisconsin say the 70 mph speed limit appears to be working with few issues.

Marquette County Sheriff Kim Gaffney, vice president of the Badger Sheriff's Association, said the 70 mph limit isn't a topic discussed at association meetings - not like drunk driving or texting while driving. I-39 runs north and south through his county and Gaffney's deputies handle the exodus heading into northern Wisconsin on Thursdays and Fridays and the southbound return on Sundays.

"Do we have accidents? Sure, we do. But I think they're more to do with radical behavior of the driver rather than the speed limit. They're usually impaired in some way," Gaffney said.

Juneau County Sheriff Brent Oleson said it didn't take motorists long to bump up their speeds and get used to the new limit, but that's probably because they were already comfortable traveling 70 mph. I-94 bisects Oleson's county.

"There's no doubt speed kills. The faster you go the more likely you'll be killed," said Oleson, president of the Badger Sheriff's Association. "75 mph compared to 55 mph, it's almost a third less reaction time and the average speed on the interstate is probably 75."

State Sen. Devin LeMahieu sponsored the 70 mph bill in the Senate along with Rep. Paul Tittl, R-Manitowoc. Among the reasons to increase the speed limits was the fact that many drivers were already traveling 75 mph or faster on the interstate, said LeMahieu, and a 70 mph limit is more in line with speeds already being driven.

"People drive as fast as they think they can. They're not always driving at the speed limit. The safest place is to drive within the 85 percent mark," LeMahieu said, referring to the average speed traveled at or below by 85 percent of drivers on a roadway, a measure used by traffic engineers.

While the 85th percentile is used by higher speed limit advocates who say it reduces crash risk by narrowing the variation of speeds among vehicles, the Insurance Institute for Highway Safety disagrees. The institute cites numerous studies of travel speeds to show that the 85th percentile increases as speed limits do - meaning the average speed 85 percent of people travel at or below goes up when the speed limit is raised.

LeMahieu, whose commute to Madison is a little over 100 miles, said Wisconsin's interstate system is built to safely handle 85 mph speed limits.

"Not that I'm pushing that. That's how our interstates are built," said LeMahieu, whose district includes I-43. "I encourage people to pay attention while they're driving, don't text or email, don't eat a Big Mac. Pay attention."

Traffic fatalities across the nation, which had dropped for several years earlier this decade, began increasing in late 2014, according to the National Safety Council. The council's preliminary estimates for the first six months of 2016 showed a 9 percent increase nationally in traffic fatalities - more than 19,000 deaths on roads - compared to the same period a year before.

Meanwhile with average gas prices in the U.S. 16 percent lower than in 2015 and more people driving, the number of miles driven the first half of this year rose 3.3 percent.

When gas is cheaper and unemployment is low, more people purchase vehicles and travel to work and on vacations. Winter weather conditions are another factor affecting the accident rate in Wisconsin. People tend to drive slower on snow- and ice-covered roads or they cut down on travel and stay home when the weather is bad.

Inattentive driving has rapidly increased as smart phones become more like an extension of people's hands, a device fewer multitasking people are willing to put away while they're driving, said David Pabst, director of transportation safety for the Wisconsin State Patrol.

Pabst has noticed a difference in speeds as some drivers get used to the 70 mph speed limit, some continue to travel at 65 and some step on the gas even more. When traffic bunches on some interstates across the state, especially during peak travel times, it's often because some motorists are traveling at 70 plus while others aren't comfortable going that fast, Pabst said.

"We didn't see a huge increase overall but as people have gotten used to that speed some of the higher speeds are creeping back up. People are getting used to 70 and then driving even faster because (they say) 'I need to get where I'm going,'" said Pabst.

Pabst was driving his personal vehicle on the interstate in western Wisconsin this summer "when I was passed by three cars going 15 mph over the 70 mph limit. They were going crazy fast, just cruising," Pabst said. "I thought 'this is why people die. You're given a speed limit increase and you go even faster. You're not going to get home alive.'"

While there are advocacy groups against drunken driving and distracted driving and campaigns to increase seat belt use, there's no concerted effort to cut down on speeding.

"There's no MADD (Mothers Against Drunk Driving) against speeding. There's no call to arms. But speeding contributes to just as many fatalities as drunk driving," said Kara Macek, communications director for the Governors Highway Safety Association.

"It's also hard to point the finger at yourself. It's still socially acceptable. Everybody goes a little above the speed limit," said Macek, adding that it's no longer acceptable to drink, or drive without wearing a seat belt.

"We've changed the tide on those two issues culturally - drinking and buckling up - but I'm not too optimistic we can do that with excessive speed. Increasing the speed limit is not a step in the right direction."