That was my average speed on my 23 mile commute from Menlo Park and across Santa Clara County last evening, according to my cyclocomputer which only measures time when I'm actually moving. I spent 14 minutes waiting at red lights and stop signs. If I divide 23 miles (the distance) by 1 hour 27 minutes (the actual wall time spent in transit), my average speed drops down to 15.9 mph.
drop me a line. In the mornings, I leave San Jose near the Shark Tank at either 6:55 AM or 7:30 AM. In the evenings, I pass through downtown Palo Alto a little after 5 PM. I can't usually leave work that early so the evening ride is fairly rare.
I'll take any of several routes. Coming from San Jose, these are:
1. Any of various routes to Central Expressway, then Rengstorf, Middlefield, University (the fastest route).
2. Park St, Monroe, Evelyn, California St in Mountain View, Wilkie Way, Meadow, Bryant (the bike-friendly route).
3. Park St., Homestead Rd, Foothill Expressway, Page Mill Rd, California Station underpass, Bryant (the fun route).
4. The Alameda and El Camino Real straight up the Peninsula (the crazy man's route).
I'm flexible if you need to stop off at an intermediate point, e.g. if you work at Google or NASA I'm willing to go that way and hop on the Bay trails that lead into East Palo Alto.
I'm an assertive rider, but I do stop at red lights and yield proper right of way at stop signs. The 18+ mph average speed is on my road bike; when I'm on my pannier equipped commuter or my fixed gear bike, my average speed is closer to 15 mph, sometimes even less. If you're faster than me, I'm an incurable wheelsucker.