Here’s 10 reasons – note this is city-specific (Boston for me). If you’re in Southern California, it’s probably too far to drive everywhere; if you’re in New York, you’d probably get hit by a cabbie; if you’re in Montreal, you’re probably biking anyways.
1. Burns calories

Fondle!
Biking will be good for your diet. If you weigh 150 pounds, you can burn anywhere from 400-1000 or more calories per hour, depending on your biking speed. Think about how long you have to run on the treadmill at the gym to burn that much. If you bike 30 minutes to work and back, you’ll can probably skip your gym workout; or better yet, still go and accelerate your weight loss!
2. Burns fat, builds muscle

Lance Armstrong has big muscles
Not only does biking burn calories, it also helps build muscle while burning that fat. You can lose weight just by dieting, but then you’ll also lose muscle.
3. Reduce your carbon footprint

Make every month bike month!
A bicycle’s carbon footprint is tiny compared to a car’s – it is much better to manufacture a bike than to manufacture a car. After that, you also won’t be burning your dollars away in the form of gasoline. Which brings me to the next point.
4. Cheaper

This is what happens when our police departments can't afford gas. I can probably outbike them.
A bike is cheaper than a car – there’s an upfront cost, and that’s pretty much it, excluding tune-ups and replacements if you need them. And then there’s the cheaper energy source – your legs! No need to pay $4 per gallon for gasoline.
5. Reduces traffic and congestion

And you got scared in your car next to big trucks...
Cars take up an entire lane in width, and several feet in length. Bikes can easily fit two to a lane in width, and sometimes just squeeze on the side of the road anyways. Drivers might complain about cyclists blocking their way, but it’s usually for a short distance; and if they’re driving that fast, there’s no congestion anyways!
6. Racing actually means something

Like dominoes
Now of course there’s kill in racing on tracks and such, but I never understood the fascination of gunning your engine and pitting your car against the car next to you. Obviously whoever wins either has 1) the better car or 2) no fear of getting arrested. On the other hand, passing another bicyclist up actually shows your physical superiority.
7. Not that slow anyways

Bicycle vs. Car
It’s going to be different in every location, but for the city streets of Cambridge and Boston during rush hours, a bike is often just as fast if not faster than a car.
8. Break laws with impunity

Training camp.
A cop is much less likely to pull a bicyclist over for running a red light.
9. Wear spandex

Hot...why are their uniforms also phallic?
Bicyclists get to wear spandex in public and get away with it. How many other people can say that?
10. Free parking

Don't know what to say about this picture.
Parking a car sucks in the city. Locking up your bike is easy. Of course, there’s the fear of getting your bike stolen, but get a good lock and there’s just about an equal chance that your car window will be smashed as your bike will be stolen.
Walk Slow, Run Fast
Introduction
I’ve had to walk around quickly today, and it’s made me unhappy. I’m a rather slow walker – a leisure walker – to the point that people walking with me sometimes complain. Yet when I go running, no one wants to come along, even if I offer to jog at a slower pace. I’ve even seen Facebook groups decrying slow walkers – but more often than not, the people that walk quickly run slowly or even not at all.
I’ve thus decided that there are four main categories of people, outlined in this chart below.
Run Walk Categories
People in Category 3 and 4 are special cases, to be discussed later or never. In this post, I will compare Category 1 and Category 2 individuals. I will break this issue down into efficiency, time, attractiveness, and personal satisfaction.
Efficiency
Walking and running have different rates of efficiency. At slower speeds, walking is more efficient and at higher speeds, running is more efficient. This happens because walking and running have different methods of conservation of energy and momentum. Walking has potential energy and kinetic energy out of phase, and running has them in phase. To save time and boredom, think of walking like a pendulum and running like a spring. We can then compare power-walking to this following chart of the energy efficiency of walking and running, drawn from Life Sciences 2:
Run and Walk Efficiencies
At approximately 2 meters/second, running becomes more energetically efficient than walking. This converts to 4.47 miles per hour. From a less academic source, Wikipedia states that power-walking is between 4.5 to 5.5 miles per hour. This means that power-walkers are walking at a time when running would be more energetically efficient.
Thus we have a win for Category 2 (walk slow, run fast) – but what about the other aspects of this debate?
Walk Slow, Run Fast: 1
Walk Fast, Run Slow: 0
Time
Now how about time savings? It is true that if you are only looking at walking, then walking faster saves more time than walking slowly. But we must also consider the running part. Since you rarely see people running in their thick wool coats, we will consider running in terms of exercise.
Let’s first assume that we walk from Leverett House to the Science Center, round-trip, two times a day. The total distance traveled is 2.4 miles (0.6 miles x 4).
Walking to Class (0.6 miles)
If a power-walker speeds to class and back at a rate of 5 miles per hour (average power-walking speed), and a slow walker travels at merely 3 miles per hour, we can calculate that a power-walker spends 28 minutes, 48 seconds walking to class. The slow walker takes 48 minutes. The difference is 19 minutes, 12 seconds.
Now let’s say that both the power-walker and the slow walker hear from the popular media that exercising off or reducing consumption of food by 500 calories a day will lead to one pound of fat loss per week. While we must control for the increased speed of both individuals due to weight loss, let us assume that their diet plans are failures and despite their exercise, they maintain the same weight. The slow walker is now the fast runner, and maintains a brisk clip: a 6 minute mile. On the other hand, the power-walker is now the slow runner, and can only do 10 minute miles.
We can calculate calories according to my guide from an earlier blog post (http://darrenhe.com/blog/?p=71) using the Compendium of Physical Activities Tracking Guide [link]. Running a 6 minute mile (10 mph) has a METS of 16.0. With a weight of 70 kg (154 lbs), burning 500 calories requires 26 minutes, 47 seconds. On the other hand, running a 10 minute mile (6 mph) has a METS of 10.0. At the same weight, burning 500 calories requires 42 minutes, 51 seconds. The difference here is 16 minutes, 4 seconds.
The power-walker thus saves 3 minutes, 8 seconds after combining the time differences for walking to and from class with exercise time. However, in the course of a day, 3 minutes is insignificant. Furthermore, that depends on the weight of the individual and the number of calories desired. At a lower weight, running faster saves even more time; also, burning more than 500 calories will also tip the scales towards fast-running time savings.
I’ll have to call this one a tie, because the difference is very small and the margin of error is large. Let’s move on.
Walk Slow, Run Fast: 1.5
Walk Fast, Run Slow: 0.5
Attractiveness
What is more attractive, category 1 or category 2? This is a strictly personal preference, but there are some general social norms that we can look at. Let’s group this again by walking and running.
Walking: Walking quickly gives the impression that you are busy, important, and “going-somewhere.” You know the city you live in and you have no hesitation. Walking slowly, on the other hand, is characteristic of tourists, which tends to be frowned upon. However, walking slowly is also a characteristic of “cool” in urban America.
Running: Running quickly is hands-down more attractive than running slowly. Whenever I see a slow runner scrape by, involuntary twitches ripple across my face and I think, “Why even bother?”
Runner
Whether we rule this as a win for Category 1 or Category 2 is up to personal discretion. But since I live in Cambridge/Boston, being urbane is much more important than being “gangsta-cool.” Thus we have another tie.
Walk Slow, Run Fast: 2
Walk Fast, Run Slow: 1
Personal Satisfaction
What is more satisfactory? Let’s consider it case-by-case:
Walk Slow/Run Fast: Double satisfaction. The phrase “stop and smell the roses” is no longer applicable when you walk so slowly that the roses wilt while you walk by. You have time to say hello to your friends, listen-in on private conversations, and slow down traffic as a bumbling bystander. And when you go running, you feel the refreshing breeze across your body, wicking away your sweat. Your heart rate is higher, and you get that feeling of accomplishment after your run.
Walk Fast/Run Slow: Double failure. You accidentally walk by your friends without saying hello, you have to read about accidents that happened right next to you in the news, and you have to bump and jostle the homeless men as you scurry past them. Then when you go for a slow jog, sweat drips onto your arms and people look at you funny. No good.
Roses
Clear win for Category 2 (Walk Slow/Run Fast).
Walk Slow, Run Fast: 3
Walk Fast, Run Slow: 1
Conclusion
Walking slowly but running quickly is clearly superior than walking quickly and running slowly. Not only are you more energetically efficient, you are happier and will live a longer life (citation needed). While time savings and attractiveness of either option come in at a tie, Category 2 is still the overall winner. Thus I encourage you to slow down and smell the roses on the walk to class, and toast the other runners on your daily jog.
Winner!