Photo: University of Michigan

Do you love that sensation of suddenly being hurled forward when you have to abruptly slam on the brakes? If you’re in a self-driving car, the effect’s apparently even more dramatic, researchers from the University of Michigan announced Thursday. People have a tendency to jolt forward as much as 8 inches when the vehicle abruptly slams on the brakes, according to the Detroit Free Press, and that amount of movement presents a number of implications for automakers developing automated technology like emergency braking.

The U-M researchers brought 80 people of various ages and sizes to the university’s fake driverless city back in May and June, and plopped them inside autonomous testing cars. Matthew Reed, a U of M research professor, told the Freep they recorded the acceleration and how people respond to a “hard braking event.”

The Freep explains what they found:

They discovered that when passengers unexpectedly had the brakes slammed, they pitched forward as much 8 inches despite wearing a seat belt in the front passenger seat. That’s a significant amount of movement while being restrained and has implications as an increasing number of vehicles employ emergency braking and other types of self-driving technology.

Automatic braking systems tend to brake harder than you or I would, the Freep says. So for passengers inside an autonomous car, especially if they’re not expecting it, that could cause them to dramatically pitch forward. The Freep goes on:

Reed said the research could be used to help design features that automatically adjust seat belts or send out a warning sound before the brakes are applied or before the vehicle maneuvers to avoid a crash.

It’s an interesting dynamic to consider as automakers are feverishly working to develop self-driving cars and bring them to the market. A number of carmakers have staked out ambitious timelines to have autonomous cars that don’t require human intervention on the road by next decade.

Two things come to mind: humans have already proved to be terrible at taking the wheel of semi-autonomous cars when they require drivers to intervene and resume control. So I wonder if drivers would have enough time to respond to automatic seat belt-tightening or warning signals, and be more prepared before the self-driving car comes to a halt.

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Beyond that, can’t you just have the brakes not be applied so hard? I imagine that would take more finesse, where the technology’s capable of assessing how close the car is and brake at a corresponding level—but the research suggests it’s simply more about how humans react above all else.

The university announced the findings on Thursday and said the study was funded as part of a $35 million effort by Toyota to support several research institutions across the U.S.