No, there really is no standard.
Most runways at regional or international airports are 100-150 feet wide regardless of length. I have, however flown into a number of ex USAF bases where the runways were 300' wide or more (I guess B52's don't like crosswinds).
The same holds true for many general aviation airports. I have seen some runways that were 30' wide or less and some that were 300' wide, usually the old WWII training bases on the east coast (if you've ever flown a big taildragger you know why!). Beaufort, NC (MRH) is a great example.
A good rule of thumb to figure out runway width and length is to look at the markings (those runways that have them). The number of stripes across the runway at the threshold are indicative of width (4=60', 6=75', 8=100', 12=150', 16=200', etc.). Many runways have touchdown zone markings which indicate the first 300' of length and signs along the side which indicate each 1000' of distance.