I don't have any numbers handy but I do have a few rough rules of thumb.
For starters do not use flash. (Some experts will dispute this and indeed some cameras may have useful side effects you can take advantage of by turning the flash back on. Some cameras may also have undesirable side effects with flash, notably not only making heads of guests in front of you stand out more obtrusively but also alter the overall scene brightness in the finished picture somewhat unpredictably)
You would want a "night mode" that you select manually. If you do not have that, then for starters set the exposure compensation to minus two (minus three if you have it). The purpose is to make the camera not try to use autoexposure so much to make a night scene look like day which in turn causes other kinds of problems as well.
In "exposure compensation" the camera sets its automatic exposure for the scene as framed by the camera at that instant and given the amount of illumination (by the sun if outdoors during the day) at that instant and then darkens it by one f/stop if you selected minus 1, etc. Caution: Many folks forget to set exposure compensation back to zero and then think the camera is misbehaving hours or days later, the next time it is used.
If you are able to see any results instantly (any digital camera can show you) and you see that the colored lights are coming out nearly white then you need to reduce the exposure (which incidentally and coincidentally can speed up the shutter to reduce blurring) Unfortunately some cameras can't go far enough. You may miss a few parade floats while fumbling with the camera.
One problem some cameras may run into is that when you reduce the exposure to make the lights the most colorful, the background (store fronts, silhouetted people lining the street, even characters on the floats) fade into blackness so all you see are the lights. Trial and error (read: more fumbling) will be needed to arrive at a compromise and Main Street Electrical Parade at Disney may well have different results with the same camera settings compared with a hometown parade or Christmas tree show.