There's a reason why car horns are so annoyingly loud: If you need to get a driver's attention in an emergency and they have the windows rolled up and the radio at top volume, they'll still hear you. But what happens when you're on a bike with a pitiful metal bell?
One louder solution—if it's legal where you live—might be a whistle, like this new design from Swedish bike accessory company Bookman. It was manufactured by Acme Whistles, which first started making whistles in the U.K. in 1870.
"We wanted to create a bike whistle as an alternative signaling instrument for especially loud and busy streets," says Bookman's Johan Lidehall. "Most of our customers probably wouldn't like the look of a big horn attached to their bike, so that's why we decided on the small but loud whistle instead."
With a small puff, the whistle makes a gentle alert, but when it's really needed, the sound is piercing and very, very loud. Riding through heavy traffic, you can keep the whistle resting in your mouth, so it's hands-free. A custom shape ensures that it won't be pushed in your mouth if you happen to fall, and the neckband has a safety knot, so it can be pulled off quickly.
The only problem? In the U.S., at least, many cities and states still have old laws on the books outlawing whistles for cyclists. That probably dates from the days when whistles were commonly used by police, and you could argue it's probably outdated in all but a few places—like parts of Manhattan or Boston—where cops still regularly direct traffic with whistles.
If a bike whistle isn't legal where you live, there are still several other options. One, for those who want to sound as loud as possible, is the aptly-named Loud Bicycle horn, which is designed to sound exactly like a car horn—so drivers pay attention and know what to do when they hear it.
"I think that we will see more and more creative options for getting yourself heard in traffic, our new bike whistle being one of them," says Lidehall. "There have been several new signaling instruments for bicycles released recently—it seems like a lot of people are experiencing the problem of louder and more crowded streets."