I average 18mph (burst of up to 30mph) on a7 mile ride and I have never been unable to hear approaching cars from behind. Do I trust my ears alone? No. But I've never been surprised by Prius, Volt, Tesla Roadster, or any other hybrid or electric vehicles. In biking events or on bike paths I can even hear approaching bicycles from behind (bike chain, wind, and tire noise). So I'm surprised that wind noise overpowers car noises for you.
It's been interesting to see all the comments about this! Obviously it's struck a nerve...and danger aside, I'm happy to see a number of people less than thrilled about the idea of noisier hybrids and EVs. There has to be a better solution.
The 1865 act required all road locomotives, which included automobiles, to travel at a maximum of 4 mph (6 km/h) in the country and 2 mph (3 km/h) in towns and have a crew of three travel, one of whom should carry a red flag walking 60 yards (55 m) ahead of each vehicle.
Backup audible warning is already implemented on most trucks, commercial vehicles, municipal vehicles, etc. That is not a bad idea; the driver has limited view, and risk is higher. But that is totally different than always on noise generators.
New versions of BASF's Ecovio line are both compostable and designed for either injection molding or thermoforming. These combinations are becoming more common for the single-use bioplastics used in food service and food packaging applications, but are still not widely available.
For industrial control applications, or even a simple assembly line, that machine can go almost 24/7 without a break. But what happens when the task is a little more complex? That’s where the “smart” machine would come in. The smart machine is one that has some simple (or complex in some cases) processing capability to be able to adapt to changing conditions. Such machines are suited for a host of applications, including automotive, aerospace, defense, medical, computers and electronics, telecommunications, consumer goods, and so on. This radio show will show what’s possible with smart machines, and what tradeoffs need to be made to implement such a solution.