Check the ride carefully - you may find that like our local club that the "average" speed required for the rides is the average on level ground without a head wind - so its not expected that you will average 16mph for the entire ride. If you can hold a steady 16mph on the flats you will be fine.

Example from Cascade:
Pace
Easy: Under 10 mph
Leisurely: 10-12 mph
Steady: 12-14 mph
Moderate: 14-16 mph
Brisk: 16-18 mph
Strenuous: 18-21 mph
Super Strenuous: 22+ mph

Refers to the range of speeds on level ground without breaks. Downhills may be faster, uphills slower. Note: for rides described as HILLY, consider choosing a pace one step down from your usual comfort level