The Joker is a steel hybrid roller coaster at Six Flags Discovery Kingdom in Vallejo, California. It opened on May 29, 2016, after Rocky Mountain Construction reworked the wooden coaster Roar, welding its signature I-Box steel track onto Roar’s original support structure to create an entirely new ride experience.
Designed by Alan Schilke, The Joker blends the airtime-heavy pacing of a classic wooden coaster with smooth steel-track inversions, a combination RMC pioneered on rides like Iron Rattler and New Texas Giant. The DC Comics villain theming, paired with a 100-foot drop and three inversions, made it one of the more talked-about additions to the park’s coaster lineup.
Stats at a Glance
- Park: Six Flags Discovery Kingdom
- Manufacturer: Rocky Mountain Construction
- Opened: May 29, 2016
- Height: 100 ft
- Top speed: 53 mph
- Length: 3,200 ft
- Inversions: 3
The Ride Experience
The Joker begins with a 100-foot chain lift before dropping riders at a steep 78-degree angle into a sequence of RMC’s signature elements. The ride includes a step-up under-flip inverted roll, a 180-degree stall with head-chopper beams, and closes with a zero-g roll, all built on the footprint of the former Roar layout.
Because the hybrid track sits on wooden supports, the ride retains the sharp direction changes and pop of airtime associated with traditional wood coasters, while the steel I-Box rail delivers the smooth inversions typical of modern steel designs. Two six-car trains carry 24 riders at a time, moving through the two-minute course at a capacity of about 1,128 riders per hour.
From Roar to The Joker
Before its transformation, the site was home to Roar, a wooden coaster that opened in 1999 and closed in August 2015 after years of declining ridership. Rather than demolish the structure, Six Flags partnered with Rocky Mountain Construction on a $7.8 million project to convert it into a steel hybrid, part of a broader trend of RMC conversions across Six Flags parks nationwide.
The Joker officially opened to the public on May 29, 2016, following a soft opening a few days earlier, giving the park a rethemed marquee attraction built around the DC Comics villain rather than an entirely new ride footprint.
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The Joker FAQs
What was The Joker before it became a steel coaster?
The Joker replaced Roar, a wooden roller coaster that operated at the park from 1999 until its closure in August 2015.
Who manufactured The Joker roller coaster?
Rocky Mountain Construction built The Joker using its I-Box steel track technology, mounted on Roar’s original wooden support structure.
How many inversions does The Joker have?
The Joker features three inversions, including a step-up under-flip inverted roll and a closing zero-g roll.
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Photo: Jeremy Thompson from Los Angeles, California / CC BY 2.0, via Wikimedia Commons.