And that's exactly what the OP was asking for. In town it doesn't seem to matter to me much, as traffic speeds are much lower. Even there on my bike I keep the generator powered headlight and tail light on. But I've been out driving on the country back roads where I ride most of my bicycle miles and have seen a flashing light in the sunrise in front of me from a much longer ways off than I could have seen the cyclist even in high viz. When I caught up with him (I was on my motorcycle.) all he had was a Planet Bike Superflash. It worked great. Even in the middle of the day at those speeds, a blinky can be seen from farther away than the whole cyclist in hi-viz.

The same reason most cars and motorcycles now have daytime running lights: Good lights absolutely increase visibility, even during the day.

I use a Vis360 that has a flashing tail light that's on all the time the front light is on, and I usually use the front light. It makes me feel safer, but I'm not sure if it actually makes me safer. I did notice a woman riding a bicycle on an unevenly lit sidestreet once (there were a lot of trees making shadows) on a bright afternoon and I think she was riding a bike from REI that had lights that came on when it was dark enough. The tail light was pretty visible in the shady sections, enough that it really impressed me.

I use this:

Useful Smashing Bike Bicycle Helmet Red LED Rear Light 3 Modes Safety Tail Lamp | eBay

The packaging says battery life is 150 hours in slow flash mode (my preferred one) so I'm not really worried about it.

My life is more important to me...

Thanks for all the comments. I'm starting to be convinced, and now I think one main reason it can be more effective than hi-viz is that to see a hi-viz cyclist, the driver has to be looking in that direction; OTOH, you don't have to be looking toward a light source in order to see its light, esp. flashing light. The light "comes at you" actively, while hi-viz is passively waiting to be seen. With that said, lights do have great directional restraint which hi-viz is less subject to. Also, in many case you can see a neon lime figure far away when lights are still too far to be seen.

Really?

Have you tested it? I think 150 hours is a big exaggeration, given that it runs on two 2032 button batteries. (OTOH you can get 100+ this light for the price of a dinotte )

I rode a bike to a "public event" over the weekend. It took place on the streets as well as in a park and covered much of the small community and greatly increased the automobile traffic.

I attached a blinky to the seat post of the bike (no saddle bag). And for the 1st time ever... I zip tied a blinky to the back of a helmet. I felt much safer and more visible as I zipped around the congressed streets. I am sure if in a similar situation in the future I will use the lights again. Maybe next time.... I might even remember to turn them on.

Everything I've read says that a flashing light uses less resources than one on constant power - some sources say far less. I use a Planet Bike Superflash that takes 2 AAA batteries and the last thing on my mind is whether the batteries are going to run out. I'll check it periodically to see if it looks a little dim and if it does I just replace the batteries.

From my experience - front light is useful in the daytime. Rear not nearly as much - but it doesn't harm.

A Dinotte rear light makes a big difference, even in broad daylight.

Drivers approaching from the rear will see you directly in front of them. Additional visibility benefit of a light (in daytime) for such scenario is very small. Speed difference is much smaller - your speed is deducted from their speed.

Drivers pulling in front of you, crossing your path will not look directly in the front and see you. Speed difference is large - your speed is added to their speed if they're coming your way and decide to turn.

This at least has been my experience. Statistical data that can be found confirms that the lowest percentage of accidents are those where cars hit cyclist riding in front of them from behind. I believe fear of getting hit from behind that many cyclists share is not real - just subjective sense of insecurity. The real problem is in front.

For 30 years of cycling never got hit from behind, lots of times got hit from the front by cars that didn't give right of way, didn't see me.

This video sums up the main threat nicely IMO:

Yep...Good One.

Front light set on strobe can be a lot less effective. The more time there is between "ON" modes, the worse. Drivers spend split second to look left-right when pulling in from side roads. Drivers coming cyclist's way and turning left across their path will have more time to see the light. But they too could not notice it, or misjudge cyclist's speed or distance because of the on-off light.

Very good point!

Yes, in that video the fast flashing front light, even with less intense light, seems much more effective. The brighter light just flashes much too slowly, and like you said could be missed when a driver is glancing down the road.

I have a few of these. It's not really a lie that they still emit light days later. But, after a few long rides they get dim. Long before they die, they are useless.
I paid about $0.50 for some 2032 batteries on line. The lights are good and bright when the batteries are fresh. I use them as backup lights to carry with me. They are brighter than one might expect. In daylight and almost straight on they are effective. I paid about $3.50 for each light. If there is a group ride in the dusk or dark I might bring a couple as loaners.
One thing to keep in mind, the brightness between different lights is so extreme it will totally change the effectiveness of the lights.
I ride in the dark a lot. I test my lights by turning them on and walking away from the bike in the dark. Also I test them in the ambient light conditions that would be typical for me, like next to traffic, or with street lights.I try to position my eyes where a driver might be when approaching from the rear, like off to one side and eyes lower than when I am standing. I don't understand why everyone does not do this. It is more effective than anything else.

Also some lights are not very directional. But until you test it, you may not understand how much. My Lupine Rotlicht has no weak spots any where from 90 degrees off one side to 90 degrees off the other side. The lens does not look like it would do that, but it does.

No; I just got it a few weeks ago.

Still, if it doesn't last very long they make the same thing in a USB rechargeable that is also really cheap so I might give that a shot...

Good video. Whether or not you agree with the SIAM technique shown, it does well at showing why it happens.

But yet when crash avoidance techniques are taught to cyclists, they are often labeled as "victim blaming".

You've made very good points!

SIAM, for me, is a bit more dangerous and inconvenient to execute on a bicycle. Motorcycle goes as fast as most of the traffic coming from behind and has two big mirrors. Bicycle doing such manouver is more likely to get hit by a car from behind trying to take over. Even with a shoulder check, after a few seconds you can no longer count on no car approaching to overtake you. Not sure if I explained it well.

However, on a bicycle I do a slower and less wobbly SIAM alternative: I just look over my shoulder to be safe, than moving to the middle of the lane as I approach an intersection. That gives some of my bike's profile to be seen by cars moving across and lets cars coming from the right see me a bit earlier. I make sure not to leave enough room for cars to consider passing me on the right hand side, or to think I'm about to turn left. After that, as I approach the intersection, or enter it, I judge whether I can safely move a bit to the right of my lane.


"Victim blaming" for me is often another word for not doing what you can to help yourself. A wise driving instructor I recently talked to said: "Good driving is not about making no mistakes. It is about predicting, correcting, or avoiding other people's mistakes."

Exactly. But for me, I ride lane center or left tire track by default, at all times (in the USA driving on the right-hand side of the road). Works great and greatly reduces the chance of close passes. Also since I started riding in this manner over 2 years ago, I haven't had a single SMIDSY-type of pullout from my right side, zero.

I think it's better to be seen than not to be seen. Speed difference is highly dependent on the particular road in question. Anecdotally, bikes with no rear lights are easy to miss unless the rider is wearing high visibility clothing. It's not just getting hit from behind that's a problem but getting right hooked from cars approaching from behind. If the light is bright enough (and the Dinotte in strobe mode is VERY visible) you can be picked up for over 1/2 mile away even in broad daylight.

I often go to the right tyre track. Depending on the situation. Whenever there's no risk of doors opening or cars pulling in from the right, I leave room for drivers to pass me within my lane. But when it's not safe, I make sure to take the lane. I believe this is corteous to other people - me being much slower sometimes. My philosophy is that bicycle (and motorcycle) are not 4 wheeled vehicles with all the good and bad sides to that. One of the good sides for me is filtering. The good side for cagers is the fact that often when it is safe they can pass within the lane, there's enough room.

Drivers do not right hook you because they don't see you from behind. They right hook you because after they pass you, they stop thinking, or misjudge your speed. How does rear light prevent right hook when you're no longer in front of the car?

As the days are getting shorter I've been riding with a front flasher and immediately noticed a difference in drivers behavior toward me. I'll be staying with it.
I generally ride a rear flasher, it's free, it can't hurt and has a real effect in low sun conditions (ie commute hours).

Hy-Viz is certainly noticeable to most people, except the 8% of men who are color blind.
I have a color blind friend who can't tell screaming hy-viz lime green from beige. But he can see a white flashing headlight like anyone else.

simple answer:

why not?

Hi Viz works when it is lit. Daylight and when lit by car lights. This makes it next to useless for cars pulling in from the sides at night. Doesn't hurt, but not as useful as it seems.

In dusk and dawn, as well as in the dark - lights are a good thing that helps. But in broad daylight. I doubt rear makes any difference at all. Front perhaps, sometimes.

I use helmet-mounted front and rear blinkers. I figure there's no such thing as being too visible.