We consider our bike lights like our yoga tights-important enough to spend the extra money on.
In "RAAM" Race rules you are required to have a vehicle behind you at all times from 7pm-7am. The headlights from your support vehicle are critical in lighting up the road for you. Even with direct access, you still need lights in the front and back, as well as reflective tape.
How are bike lights different from each other? Generally they are classified by the lumens they put off.
LUMEN: a measure of the total amount of light that is visible to the human eye that a source puts off. The higher the lumen, the brighter that light will appear. In the bike light world the higher the lumen is, the more expensive the lights will be.
For direct follow races I like these Cygolite lights. They are easily mounted to both a tri and road bike and put off enough light to compliment the headlights of your support vehicle. With 150 lumens they are not adequate for night riding without direct follow. Left on low beam they last a really long time. They are are not pricey so buying two sets and swapping them out when they die is my strategy. When completely dead they take two hours to recharge.
So what happens when you are racing without direct follow? Well, you need to be LIT UP like a Christmas tree. Even if you have night vision like Spiderman, you are still going to want good lights. Remember, you want to make sure that vehicles on the road see you too.
I use a larger, heavier Cygolite for racing at night without direct follow. At 1100 lumens this light puts off some serious light! Pros: you can see with it. Cons: It is not made to run on high for extended periods of time (high light only last 90 minutes!) On "medium" setting it last for 3 hours. Low setting it lasts for 10 hours. Both the 1100 and 850 lumen provide a lot of light.
Because I am blind in my left eye and don't see well at night I will always have a back up light on my bike. The smaller cygolite with 150 lumens isn't ideal to be totally lit up, but will work in a pinch if your main light dies.
The last thing you want is to get caught on a loop without adequate lighting. The wonderful thing about lights that are rechargeable is that you can charge them while you are riding with a portable charging bank, and cord. Same goes for your bike computer, which likely will not last 24 hours without being charged. Don't expect roads to have street lights for you to see at night, in fact you should assume the opposite. It will be pitch black and you should be prepared to race in total darkness.
I have tried battery operated lights. While they do last a really long time, they do not put off enough light for me to consider them safe at night. The planet bike rear light pictured here is okay for daytime training . Also pictured is a Serfas and Lenzyne light. While both of those are rechargeable neither lasted halfway through training rides on blink mode so I cannot recommend them for either racing or riding.
NOTE: We ended up with a lot of cygolites because this was a brand we used that worked and rather than having a bunch of different mounts that we needed to change, we continued to buy this brand of lights. There are likely many other brands that work well out there.
Some people choose to wear lights on top of their helmets. Added benefit of this is that you have light pointing to wherever you move your head. Personally this added weight is not comfortable to me. However, if you bring a back up helmet (and you should always bring a back up helmet!) you might consider adding a mount to it for a light if you have one. Practice riding with both set ups to see what is most comfortable for you.
Reflective tape: This is required by most races to be applied to your bike in various places. Some races require it on your cycling shoes as well. Apply electrical tape first, then reflective tape over it for easy removal.
Reflective vests: Required at some races, recommended at most events. If you have any crew that will be on the road they are required to wear safety vest at night too.
Tips for racing at night:
Make note of what time you turned your lights on and be proactive in changing them out/charging them BEFORE they die.
Make sure that you have back up lights and that they are charged.
Don't assume the race will provide a power source to charge lights with. Bring an inverter. Don't leave a million things plugged into your car charging at once.
Portable charging banks are an easy and inexpensive way to charge both phones and lights. Stock up!
Invest in clear glasses to wear at night. If you have never ridden your bike at night practice to make sure you are comfortable with your light set up and the differences in depth perception night riding may present.
Don't look directly into the high beam lights of oncoming traffic.
Make sure to read the rules specific to your event. Follow all guidelines for support vehicle signage and amber lights (if required). Remember that most race directors #1 goal is your safety. Many races take place in areas where there is not much traffic at night but that does not mean you will avoid all vehicles. Make sure you are shining so bright they have no choice but to stop, mesmerized by your glow.