A new study claims Yosemite National Park's permit system doesn't improve safety for hiking Half Dome/NPS

You can debate long into the evening whether the hike up Angels Landing in Zion National Park is more terrifying and dangerous than the one to the roof of Half Dome in Yosemite National Park.

At Yosemite, however, park staff some years back decided the crush of day hikers heading up Half Dome was increasing the riskiness of walking up a 45-degree slope, and so they implemented a permit system to limit hikers.

Now a study claims that permit system does not reduce the risk for hikers.

I've hiked both trails, and must admit the final stretch to the summit of Half Dome is scarier and, indeed, very likely more dangerous than the trail up Angels Landing. Nowhere on Angels Landing does the trail head up a 600-foot stretch of slick granite that at points reaches a 45-degree angle. And for day hikers, that stretch is tackled after they've hiked half of the 14.2-mile roundtrip. Under a glaring sun, that alone can tax you.

Getting in line to tackle the final stretch, which the Park Service makes somewhat easier during the summer months by installing cables for handholds and two-by-fours as slight steps, you gaze up the steep pitch and the line of people in front of you and you feel a shiver down your spine and sweat forming in the palm of your hands, even with work gloves on to better grip the steel cables. 

Hesitating isn't always an option, as there can be a line of people forming behind you, anxious to reach the summit. And as you head up, others are coming down, some still swimming in the euphoria of standing atop Half Dome and gazing down into the Yosemite Valley.

Through the years, at least eight hikers have slipped and fallen to their deaths from Half Dome's shoulder. Most slipped and fell after, or during, rainstorms. Some suffered heart attacks. Back in 2007, a woman tried the hike before the cables had been installed. While she made it to the summit, she fell to her death on the way down.

In 2010 the park implemented a permit system to try to keep the number of day hikers on the iconic rock to what seemed to be a manageable number. Whereas some days prior to the permit system saw more than 1,000 hikers tackle the route, the permit system was intended to keep the number to 400 a day.

A study at the end of that first summer of permitting found that the permits didn't make the hike any safer. While the permit system for folks hoping to summit Half Dome on weekends and holidays did indeed tamp down those crowds, the 2010 study said it also had the "unintended consequence" of moving the crowds to weekdays, when permits were not required. In the end, the study concluded, "these results suggest that the objectives of visitor safety and acceptable experiential conditions on the cable route cannot be provided with a daily visitor use permit system implemented only on some, but not all, days of the week."

So in the wake of that study it was decided that permits for Half Dome would be required every day of the week going forward.

But now, a new study claims even that approach doesn't make the hike any safer.

While the permitting did reduce the overall number of hikers heading up Half Dome by 66 percent, there wasn't a corresponding decline in accidents.

SAR incidents, victims, fatalities, or costs above (Little Yosemite Valley) did not decrease after cable handrail permitting. Parkwide SAR activity decreased during the same intervals. This strongly suggests that overcrowding is not the key factor influencing safety on Half Dome. This discordant trend warrants close observation over 5 to 10 (years).

Park staff were still analyzing the study Wednesday and weren't ready to comment on it.