R. Kelly's Tour Bus Busted in Utah!

Now TMZ knows exactly why R. Kelly was a no-show for court in Chicago -- he was left on the side of a Utah highway without a ride, after his tour bus got yanked off the road by the po-po. We ride!

Police sources in Utah tell TMZ that Kelly's four tour buses were stopped yesterday, after they were spotted going over 100 mph. After the buses were pulled over, the investigating trooper noticed that the bus drivers seemed "tired." John Q. Law then asked for the buses' log books (with drivers' rest and drive info) but they weren't on board or weren't updated -- a big no-no in Utah.

The buses were ordered taken out of service, and the passengers were left to find their own rides. No "Ignition" for R. Kelly! There's a warrant out for his arrest for his no-show at court. That warrant will be enforced tomorrow if he again fails to show.

R. Kelly's people haven't returned our calls for comment.