It takes me almost 15 minutes to cover less than 2 miles. Factor in eight stops and a red light, plus a minute of weaving past pedestrians and another 30 seconds locking the bike and helmet, removing gloves, etc, and it becomes clear that your average speed isn't always up to you. I just ride at a safe and comfortable pace and enjoy the music along the way.

Wrong. Let's translate this into hypothetical power outputs and posit, for the sake of argument, that the OP is riding at an average of 200 watts for the hour it takes him to ride 11.4 miles.

Riding two, three, four or five hours at 200 watts, per your prescribed "ride longer" strategy, is not going to increase the power he can put out over his 11 mile commute.

Rather, stressing the body with higher intensity intervals will cause the body to adapt to pedaling at 210, 220, 230, 240 watts, etc. etc.

The only thing the OP will gain by riding more hours at his current pace is the ability to ride more hours at his current pace.

Wow, you have the exact same commute as me! I have the same bike (Tricross Sport 2009, stock tyres, usually at like 40PSI cause I'm lazy...), and my commute is probably about 500 metres shorter than yours. It takes me 55 minutes to get there, and about 45 back, if I'm pushing - it's a gentle slope pretty much the whole way.

What's the problem, exactly? You want to get fitter? Go faster? Spend more time at work?

Steve

Of course he has to increase the pace on the shorter distances, that is obvious. What he doesn't have to do is ride intervals at his LT threshold. That is almost certainly not what the OP is interested in doing (I could always be wrong, but judging from context I don't think I am.)

Sounds like he wants to ride faster. He can get faster with a bunch of junk miles or haphazard training, but if he wants to get faster in the least amount of time, LT workouts are going to be the way to go. Is that going to be easy? No. Will it make you faster in a short period of time? Yes. You don't get faster without work.

On Saterday or Sunday mornings I get to work 5 minutes quicker because I am not waiting to cross any street or wait for traffic. I do slow down, but to coast so that I don't get tired out. I always wondered if I would get to work quicker if I never had to stop.

I don't consider my long, moderate rides 'junk' miles. I consider them fun. My whole point, though, was that someone who is riding at 11mph has probably not been training much and telling him/her to do LT workouts is not very practical unless he works up to that point through more gentle training.

Just didn't explain myself well.

You'd get there earlier but ride right past...

To save a little wear and tear on my body, I try not to make my commutes to/from work a sprint or workout the way I would on weekend fitness rides.

I have also found that it is a psychological bonus to not always make commutes to/from work "hammer time". That said, I've pushed pretty hard when I've been joined on my rides home from some of my friends that commute on their road bikes but that is a pace I can't realistically maintain.

Not to mention, the bike fit on my commuter converted mountain bike just isn't up to par with the "fits like a glove" fit of my road bike.

With a bike rack and loaded bike bag, it's more about getting from point A to point B safely and with the least amount of stress. I've had a few situations where my slower speed has helped to prevent accidents (e.g. a lady just the other day made a right turn directly in front of me but with my reduced speed I was able to brake and stop with time to spare).

If a slow to medium speed on your commutes helps you be more vigilant in monitoring traffic, road hazards, etc. than the time expense is well worth it IMHO...

Your time is about right for commuting. Hammer the whole way one day and see if you enjoy that. I tried it out of necessity (storms), a couple of times and always commented to myself that I would not want to ride like that every day.

Out of curiosity. What's your hurry?

Same here. There are 29 minutes between my target time to get out of the house (5:35) and when my train leaves (6:04). If I leave later, I try to go faster. Typically I ride 15-20 mph, but some of that time I'm stopped, or slowed down for a turn, or whatever. It is simply impossible to maintain a target speed, such as 17 mph, for the whole time one allotted to being on the bike.

Bicycling is like fishing. An awful lot of 12" "monsters" out there I have no doubts that there are people who can sustain 20mph averages over the course of a ride. I've done close to that on centuries and shorter rides but, while riding in an urban environment and obeying the laws, it's difficult to go much faster than about what you are doing. At least that has been my experience. Some days I might go a little faster than normal and others I'm going a little slower. It depends largely on conditions. Cold makes you slower (most mornings are cooler), wind will do the same, climbing makes you slower, Fridays make you slower, etc.

Don't be in a hurry. You're just going to work

I have averaged 20mph on a 70 mile ride. Guess what I average on my 23-28 mile each way commute.... 14-15 mph. I would not sweat the small stuff. Your speed will come up eventually.