AKA Cannonball Run III. Or not.
Originally devised as a third Cannonball Run movie, Speed Zone has to settle for being a very poor distant relative to the first two movies. Thankfully, it has a role for the very likeable John Candy and that saves it from being completely unwatchable. That's not to say that, for some reason, those involved don't keep trying to make as many bad choices as possible.
The plot is as slim as it was in the previous Cannonball Run movies (that this isn't actually a sequel to but we all know that it is, really). A race across the USA allows drivers to drive various cars at illegally high speeds and everyone involved really wants to win. End of central premise. Of course, people have different motivating factors and skillsets. Matt Frewer, for example, plays a man who keeps trying to win by using his wiles as well as his driving skills. John Candy is just a nice, steady guy who reflects that in his driving style, with the lovely Donna Dixon overacting badly as his passenger. Eugene Levy may not actually drive in the race but his double-decker hairdo deserves at least some kind of consolation prize.
Directed by Jim Drake, and written by Michael Short, there just isn't enough of anything here to please fans of, well, anything. The cast includes those already mentioned plus Peter Boyle, The Smothers Brothers (two men I took an immediate dislike to, I'm afraid), Melody Anderson, Shari Belafonte, Tim Matheson, Art Hindle, Brian George, Joe Flaherty and then cameo roles for Jamie Farr, Brooke Shields, Michael Spinks, Alyssa Milano, Carl Lewis, Lee Van Cleef and some others. The automobile action isn't all that exciting, although one or two stunts do stand out as high points. Then we have the comedy content, which isn't all that great in terms of quantity and quality.
I suppose the biggest failing with Speed Zone in comparison to the Cannonball Run movies is summed up thus: The first two movies featured stars of yesteryear having a lot of fun together with one or two new faces joining in with the fun. This movie features a number of relatively "new" faces having fun with one or two stars of yesteryear joining in. That shouldn't be enough to make this such a bad movie but it is. It highlights just how much great chemistry, charisma and goodwill was thrown onscreen during the first two movies.
If you're an obsessive completist then you'll still want to get a hold of this but I don't recommend it (and I'm the guy who bought Jaws: The Revenge on DVD because I had the preceding three movies).