All my commutes are on vintage road bikes. Since I have to merge in with rush hour traffic a lot, I have to move quickly. On my 79 Raleigh Competition GS, I have a computer. I have been noticing when I was leaving work, on a slight decline I am pushing 31/33 mph. I got a thrill out moving to the left lane in passing a slower moving car., . Closer to home on a flat section I am up to around 23 mph..

I have to take the full lane a lot of times on my commute, and traffic is moving quite fast.
Most of the time my speed is around 15-18mph, so I could say that is my average speed.

I have no idea how fast I'm actually moving during my commute. I don't have any kind of speedo/computer on the bike. I do things the old fashioned way. "OK.....It's 20 miles....and it took 1.5 hours to do the commute.....that's about 13.5 mph". Of course, that timespan includes time spent sitting at traffic lights and stop signs.

So, how fast am I really going? Fast enough to sweat and breathe hard.

Too many variables. Weather, wind, how I feel, down hill, up hill, etc.

I would say on the way to work, where I get most if not all of the head wind, it is between 13-15 mph. On the way home, it could be 15-18 mph. Depends on wind, how I feel, how the knees are doing, weather, and how heavy my load is. I have to take a lot of stuff to and from work so panniers are usually packed.

I actually track stuff like that on bikejournal.com and for the month of June, my average speed was right at 17. More than 80% of my miles for the month were commuting miles, so I have to think that my average commuter speed would be right at 17. I commute about 7.5 miles each way on a Bacchetta Giro recumbent. It may be a bit faster in July as I have just changed the tires to 26"x1.125" Gatorskins running at 105psi.

Tractor Tom in Okeechobee, FL

Well, one day I averaged 23mph, but that was when I was doing a comparison driving the company pickup truck. When I'm riding my bike, my speed is between 14 and 18 mph. There are many uncontrolled variables, such as traffic lights, traffic, and wind. The distance is only 4.5 miles. There are several stretches where I'm able to ride the speed limit and keep up with traffic if the wind isn't against me.

From reading all the responses, it can be safe to say that that average commuter speed for all commuters is about 13 to 18 mph.. Some commuters have spots (decents) where they can boost up the speed to 30mph but that is not average, more of an exception. I travel light. Only a small backpack, no panniers.

I average about 15 measured the same way SkippyX does. I hit about 35 on one downhill section but I'm just coasting there. It's my reward for the long slow slog up to the top of that ridge.

I have been reading a bit on this forum on what people consider as average speed. There is a lot of definitions. I like the Distance/hours formula. My commute is 4.2 Km which I do in 11 minutes which gives me an average speed of 23 Kph or 14 mph. The time is different from day to day, but when you average this over a few months, it is pretty consistent.

My non-parking lot portion commute home generally takes 28-30 minutes rolling time, so the speed home is 2 to 2.1 commutes per hour. To work is slower,30-32 minutes. 9.3 miles.

Total time door to door including parking lots and waiting at lights varies 33 to 38 minutes. So, (9.6 miles) 15-17 mph.

I ride 11 miles one way. On the way to work I'll average 17mph, almost all downhill. Coming home, I drop to about 13mph. Going home is really hard with temps in the 100 degrees. Can't wait till fall.

My commute is a nearly flat 5 miles. I have gotten my moving average on a commuter hybrid up to just over 15 (17 on the road bike). It's right around 11 including stop lights. I seem to hit all of them.

My commute is 33 miles rt w/a 500 ft elevation drop on the workward leg. Working 2nd shift allows me the luxury of averaging between 17-19 towards work and 15-17 on the way home. It's rural w/6 stop signs spread out over the 16.5 miles. No traffic lights. Very little traffic and the roads either are well paved secondary or a primary w/an 18-36 inch shoulder area outside the white line. There are better paying jobs out there for what I do, but I wouldn't trade my commute for any of them.

flat-bar knobby-tired MTB.

11km (7 mile commute) each way, so roughly 22km (14 miles) RT.

my rolling average speed is 22km/h and the rolling time is right at an hour. i seem to hit a huge amount of stop lights and ride through the pedestrian zone (no cars / bikes at walking speed) both ways because I like to grab a baguette/meat for breakfast at work or something to eat on the way home.

edit 1: it seems that my total time is roughly 35mins ... meaning i spend roughly 5 mins stationary each direction (stop lights and with make purchases ... food/beer/etc...)

edit 2: when I ride with the gf, our time is slower, roughly 35 mins rolling each way (70 mins total) ... so roughly 12 mph. but, it's ok with me as it's really nice to speed to with the gf commuting to work

edit 3: it would be really nice if the commute was 50% longer. I'd really like to get roughly 20 miles in per day ... but alas, it wasn't meant to be.

I take about 45 min to get to work. It's 8 miles. Some of that time is getting my bike out of the house, parking, waiting for lights etc. So I'd say my average speed is about 16 mph.

Depends on the day and the bike I ride. If I ride the commuter which is heavier, but a bit faster I can go 10km in about 30 minutes counting all the traffic stops. Obviously the time goes up if I get unlucky and get all reds. I've had it down to 15 minutes but that was a lucky day when ALL the lights were green and there were no ^&*&^* buses to block the lane, stop, make me wait, block the lane. On my 15km bike trail commute days I can get there in 30-35 minutes if I can clear the bike shaped objects in the park quickly enough. Exercising I get around 25-28km/h averages. Commuting I get 23-25km/h averages.

1h10 approx. (depending mostly on wind direction) to go 19 miles (30.5 kms)

I just started adding a few km to my commute home, 4 Km is way too short. I have a 12 km route I've taken a few times and I'm now looking at a 30 km route for next week. Would never even think of doing this in a car.

so many variables - around 20 kph for me -hilly rural terrain on a mix of dirt and paved roads

'bout 8.5 mph.

yeah, i have a nice 40k ride home mapped out (2hrs) that i posted pictures of before.

to be honest, it's more of a time issue

The swift movement of the bicycle and the sound of the wind as it slips dowward with speed, Indeed it is a reward.

I got to give you MTB riders big props!!

Off the top of my head, I would say MTB riders have to work at least 40% if not more harder than road bike riders. MTB tires, and weight adds more to the resistance. However, I have been passed by MTB on the flats,

My average on the cycle computer is normally around 11-12 mph. Cruising speed might be 1-2mph higher than that.

Regardless of what speed I do on the 'straightaways', my average speed/time on my 16 mile commute never really varies. 18mph cruising speed, 55 minutes. 20mph cruising speed (a LOT more effort), 50 minutes. My bike computer gives rolling times, so +3mins for traffic lights.