I’ve been biking to work for almost a year, so wanted to share some of the things that I’ve learned.
Route: I live about 5 miles from work. About half of the route is on an off-street paved trail, a quarter is on nice roads (residential, business parks) and the last quarter is on a busy 35 mph road with a marked bike lane. The biking layer on Google Maps is a key tool for scouting out a route, although I’d recommend using Street View to confirm that all of the roads are bike-friendly before trying them (e.g. Central Expressway is marked as bike friendly).
Showers: I sweat a lot. In the summer after a run it looks like I also hopped in a pool. So having a shower at work was absolutely critical for me. Your mileage will vary depending on how easily you sweat and if you wear a backpack, but having a shower and changing room at work is an important consideration.
Panniers: I bought a pair of Ortlieb panniers a few years ago, which was a fantastic investment. Compared with a backpack they are waterproof, can carry much more weight and volume, and keep your back dry (see showers above).
Lighting: I have four lights: two attached to my helmet using velcro and two attached to my bike. The front light on my helmet is a 2W LED beast so that I can see on the pitch black trail at night while the other three lights are generic bike lights. The front light on my helmet also serves as a headlamp when we go backpacking. Maybe the most important part of the lighting setup is a good set of rechargeable batteries. Eneloop is the best option here by far and puts NiMH to shame. Any charger will work; I have this one and it works great.
Clothes: I usually wear the same clothes I would go on a run in; shorts and a synthetic short or long-sleeve t-shirt. If it’s cold, I have a dayglo windbreaker and gloves in addition to a headband that keeps my ears warm under the helmet. If it’s really cold then I pull out the balaclava and as a bonus get to scare people.
Other gear: I have a set of plastic fenders for winter, although it’s about time to take them off for the summer. They aren’t my favorite things in the world, but they do their job. I also don’t have them mounted perfectly so they interfere slightly with the operation of my back brake, which is why I’m eager to take them off for the year. Also, clipless pedals are a must and make biking in general so much more enjoyable.
Safety: I’ve never had any issues with cars even though I bike home in the dark about six months out of the year. This is probably due to the combination of my dayglo jacket, four lights and I’m on a car-free trail for about half of the trip. My main issue has been biking with slippery conditions when it’s rainy and I’ve had three relatively minor solo accidents. All three accidents were on one region of the trail and caused by slippery road markings (two accidents) or biking too fast down a wooden bridge (my bad).
That’s about it. So remember - lots of lights, Eneloop batteries, and panniers.