"Speed Zone" is really "Cannonball Run III," and I say that not just because this is nothing more than another mindless car crash movie with a lot of cameo guest stars, though it certainly is that. "Speed Zone" really is a sequel as another bevy of speedsters gathers in Washington, D.C., for an illegal Cannonball race to California, and the cast includes Jamie Farr as the same sheik he played in the two "Cannonball Run" pictures.

But the question is, is this one as bad as the other two? Well, what can you say about a chase sequel that even Burt Reynolds won't appear in?"Speed Zone" has no plot aside from idiot drivers trying to pass one another on the highway and wrecking a lot of cars. Among them, John Candy as a sweet if silly parking lot attendant, with passenger Donna Dixon as a Marilyn Monroe clone; Joe Flaherty as a hit man riding with his fey victim Matt Frewer; the Smothers Brothers as quarreling rich brothers, one perpetually playing with his yo-yo; Shari Belafonte and Melody Anderson as the required brainy but beautiful women pretending to be bimbos; Tim Matheson and Mimi Kuzyk as TV news reporters covering the event; Peter Boyle as the crazy police chief chasing all of them; and, of course, various guest-star encounters - John Schneider, Lee Van Cleef, Michael Spinks, Brooke Shields, Carl Lewis, etc.

What do you suppose filmmakers think is so funny about cars running through roadblocks, crashing into each other and flying through the air? In and of themselves, none of these things is the least bit humorous. And "Speed Zone," rated PG for violence and a few vulgarities, is as witless as movies come.