Every year, my country conducts a nation-wide mandatory intelligence test of all bike riders.
Here in the fall it is getting darker in the mornings, and everyone with an IQ above 70 pass the test by mounting lights on their bikes.
Those with an IQ lower than 70 can be overlooked in traffic — it is a Darwinian system really.
@randahl
Why don't we have a law mandating bikes have permanently fitted lights from the dealer?
Forget those cheap lights with batteries that are always dead when you need them. LED lights use so little power that they can be permanently on without any noticable resistance. It's not like the old dynamo lights that doubled the rolling resistance and didn't work in the rain.
I've had magnet lights permanently mounted on every bike I've had for probably 15 years, and there are better lights if you have the skills or are willing to pay to have them installed.
Imagine if cars had lights as an optional extra...