340-ton boulder to begin tortuous trip to LACMA, because it's art A 340-ton boulder is expected to begin its difficult trek Tuesday night from a Riverside County quarry, rolling to a stop 11 days later in a new art exhibit at LACMA. The two-story-high rock will begin its 106-mile journey on a custom-built, 294-foot-long centipede-like transporter between 10 and 11 p.m. and travel at the painstakingly slow speed of about 5 mph. It's due to arrive at the Los Angeles County Museum of Art on Wilshire Boulevard in the wee hours of the morning March 10. The 680,000-pound boulder is so large that work crews from about 100 utility districts will have to take down traffic signs, overhead wires and other obstacles to let the rock pass and then reinstall them later. INTERACTIVE: Graphic of boulder's centipede-like tractor A signal expert will have to move and rebuild traffic signals that would otherwise be mowed down like blades of grass by the transporter--nearly as wide as three freeway traffic lanes. The rock will travel through four counties and 22 cities and is so large and cumbersome it can only move at night on roads closed to traffic. Officials also had to use a circuitous route to avoid "overpasses and any streets or bridges deemed too weak to support the transporter and cargo," according to the museum. During the day, the rock -- expected to be shrink-wrapped for protection -- will have to park in "the middle of the road, the only place big enough," Rick Albrecht, the project's logistics supervisor, told The Times last year. Initially, the plan was for the trip to take nine days, but it is now scheduled to take 11 days to reach its destination. At LACMA, the granite will be placed on its new home, resting atop a ramp-like slot in the ground through which visitors will pass, making it appear that the rock levitates above them. It will form the center of artist Michael Heizer's enormous sculpture "Levitated Mass." The total cost of the project, including the rock, the transportation and construction of the sculpture site, will be up to $10 million, which was raised from private donors. On Tuesday night, quarry owner Stephen Vanderhart will throw a reception for about 300 people to see the rock off, complete with a BBQ truck and a DJ. The Times' Culture Monster blog will be covering the event live, with updates throughout the evening. You can follow the action on the rock's own Twitter account @LACMARock. Los Angeles County Chief Executive William T. Fujioka sent a tweet to the account, saying, "It's wet out there, @LACMARock. Be sure to pack an umbrella & coat for your journey. I'm thinking size 3,428XL. Photo: Emmert Construction crews built a steel transporter around a 340-ton granite boulder to move it from Stone Valley Quarry in Riverside County to Los Angeles for a LACMA art installation by artist Michael Heizer.