Being seen is being safe, and that's every bit as important in the daytime as at night. You've probably noticed many cyclists running with flashing headlights during the day, and often flashing tail lights as well. There is no question this improves the likelihood of someone seeing you! And with the newer, inexpensive, lightweight and rechargeable lights available, why not?
Keep in mind that, when fairly close to a car, visibility isn't the issue, but rather whether they're paying attention. When driving, people "zone out" from time to time. Who hasn't at some point been driving along and realized they don't remember anything about the last 10 or 15 seconds? The goal of a daytime flashing light is to be visible for a long-enough period of time (from far away) to catch the driver's attention, because, once they're paying attention, they're not likely to forget about you as you get closer.
The lights shown below are the best of the best. These are the front & tail lights the staff of Chain Reaction actually uses, night & day.
For daytime front use, the Serfas Thunderbolt is the best in terms of side visibility (viewing angle), and its strap-on design allows it to be placed just about anywhere. Its downside is the short time between recharging; about 1.5 on high flashing mode, and 7.5 hours on normal. The Lightning Bug 150 isn't as visible from the sides, but, in flashing mode, lasts much longer and doubles as a useable light for seeing where you're going at night. If you need to see where you're going at night, the Bontrager Ion 700 can't be beat. Small package, great beam pattern with an amazing amount of light. It can also be used as a daytime flasher as well.
Do less-expensive options exist? Yes, many. But they lack the versatility, function and durability of the two I've listed here. These are awesome moderately-priced daytime lighting solutions that recharge off the USB port from your computer or iPhone charger. The $10-$30 options don't come close to what these offer.
Sync your light, see through the night Daylight visible with power to…
Daytime visible from up to 2km away A tail light from the future that…
Make every ride safer with the first tail light designed for daylight…
From the Feb 9th, 2014 Almost-Daily Diary Entry- Rant about visibility (Updated 09/13/2014)
OK, yes, some might think it a bit crazy that I did a solo ride out to the coast and back via Tunitas, in the rain. And some might think crazier yet that I look forward to that sort of thing and was bothered that it didn't really rain as much as I wished it had. People thinking such things might have a point. Especially since I had a way out, when Kevin didn't want to ride because he wasn't feeling well. Had it been nice & sunny would he have felt better? Can't say.
I finally got out the door at noon, two hours later than planned, and wasn't at all sure I'd be making it all the way out to the coast. I started thinking about alternatives; maybe heading up West Alpine instead of Tunitas? Or just doing a quick run up Old LaHonda and then maybe a loop through Portola Valley? But the plan was to ride out 84 to the coast and return via Tunitas, and why not? As usual I started feeling better as I got going, and in no time at all it just seemed inevitable that I was going to make my date with Tunitas. Besides, how long has it been since Tunitas Creek actually had water?
Water. Rain. Not enough of it, really. I had a light rain and occasional drizzle the whole ride, but none of that epic sky-is-falling stuff that legendary rides are made from. But it was pretty gloomy out there, without even a brighter spot in the sky that would let you know where the sun was hiding, and that made for ideal conditions to notice the visibility, or lack thereof, of the few other riders I encountered.
Why aren't people paying attention to their visibility??? There are modern, low-cost lights available that make an amazing difference in whether you can be seen, and it was surprising that maybe half of the cyclists out today had no lighting whatsoever, and half of those who did, had only rear flashing lights. Only a very small number of headlights, and that's just nuts. Even on a bright sunny day a flashing headlight can make you stand out from the background, and on a day like today?
There are lightweight, inexpensive, easily installed & recharged front lights that we couldn't have dreamed of just a few years ago. Lights that will help you be seen not just from the front, but the sides
Normal daytime lighting- Serfas Thunderbolts front & rear (both in flashing mode)as well. I have literally seen people at intersections do double-takes as I approached, stopping them in their tracks instead of plowing on through and requiring me to slow down or take evasive action.
Is this excessive? I don't think so. It's not even expensive. When you consider what you had to spend for a bright front light just a few years ago, spending $85 for a rear Thunderbolt and front Lightning Bug 120 is pretty reasonable, especially since they don't use disposable batteries. Double that for darker days and you're still under the price of a high-end helmet. If you want to go totally minimal, you can get something like the Blackburn Flea, but my concern with those is that there's just not enough there there. Half as bright as a Thunderbolt or Lightning Bug 120, without the Thunderbolt's side visibility or the Lightning Bug's usefulness as a night-time see-where-you're-going light.