It's the last thing that Disney's (NYSE:DIS) flagship Disneyland theme park needed. After a two-train collision at the park's Big Thunder Mountain Railroad -- the third accident at Disneyland's tame yet popular roller coaster in the past year -- California regulators have moved in to investigate the ride's unfortunate streak of bad luck.

The closure, which will last at least a couple of weeks, won't come cheap. With the park's Space Mountain coaster closed until next year, the peak summer crowds looking for thrills may have to search elsewhere.

It's not as though Disneyland ever touted itself as a haven for scream machines. Other area parks such as Cedar Fair's (NYSE:FUN) Knott's Berry Farm and Magic Mountain from the Six Flags (NYSE:PKS) chain provide far wilder coaster rides. Yet California can be a demanding state to run a park, as both of those parks had to close signature coasters last month because of a fatal accident that happened three time zones away.

Coasters have been getting a bad rap lately. While my 10-year-old son may be beaming about the 104 different roller coasters that he has experienced (yes, including that very Big Thunder Mountain that we rode two weeks ago), maybe I should be worried about being labeled an abusive parent.

While it's more than likely that more people have been killed or injured in accidents driving to the nearest amusement park than while at the site itself, these become the headlines. If a visitor to a national park is hurt, or worse, no one threatens to close the landmark down. However, even coaster accidents that clearly involved rider error have forced rides into periods of downtime.

Yes, many of the recent accidents (including the recent Disneyland collision) have actually been the fault of either the ride operator or its maintenance. Parks have every reason to be held accountable in those cases. However, the industry needs to continue to run coasters, and develop new scream machines, to stay in business.

It's not just Disney, Six Flags, and Cedar Fair here. Major companies such as Viacom (NYSE:VIA), General Electric (NYSE:GE), and Anheuser-Busch (NYSE:BUD) operate amusement parks, too. Granted, their thrill-park businesses are a thin slice of much meatier pies, but they are still significant contributors when the going is good. That means that parks must maintain their marquee attractions running -- yes, safely -- and perpetually adding new rides. Stagnancy rusts the turnstiles.

Our Travel Center may be worth a visit if you're planning a trip out to a theme park this summer -- but are you scared to ride the biggest coasters? Will rides ever be 100% safe? Which rides are more dangerous than others? All this and more in the Roller-Coaster-Loving Fools discussion board. Only on

Longtime Fool contributor Rick Munarriz hasn't been scared off coasters yet. He owns shares of Disney and Viacom as well as units in Cedar Fair.