Hazard lights

In the UK, and in much of the world, cars have a "hazard warning" which consists of flashing both left and right indicator lights together.

This causes a very simple problem, with a suitably simple solution.

Problem

When a vehicle breaks down (or in common behaviour just parks badly) and another vehicle parks behind it - they typically obscure the nearside indicator light, so the front vehicle looks like it is signalling to pull out. Drivers that follow may be cautious and think it really is pulling out, but after some time they will decide the front driver isn't moving and drive past. Repeat this many times, and eventually drivers take a flashing indicator light from a car that isn't moving to mean the car likely has hazard lights on.

Pictures to follow.

Solved

Make hazard lights flash at a different frequency, so you can see at a glance, from just one indicator light, the difference between a signal to pull out and a hazard signal. In particular, I expect flashing hazards twice as quickly would suggest the appropriate hazard-nature. Further, that would make the world better as soon as the first cars started doing it. As more vehicles adopted fast-hazards, people would become more likely to see a protruding indicator as a sign of someone pulling out, and could give them the space to do so.

There will be those who insist that the indicators really do flash at a different frequency than hazards, since there is double the load - "think about the time constant, man!". However, what matters is that the difference is not readily appreciable to a passing road-user. I am more engineer than scientist, and so am inclined to find any system that can be made to work in a real environment, not just one which we can convince ourselves ought to be mathematically fine.

Next steps

To follow through on this we should probably grasp some rough numbers for how serious this problem might be, and the cost of implementing a change.

We would need a small amount of user testing, to set the rates of indicators and hazards appropriately for all road users.

Ultimately, I imagine this could be implemented in legislation, but I have spent practically no time researching how and where the current legislation is framed. This is just an unfinished draft, but comments are welcome via email. (Please include the word tumtum in your subject line if I do not know you).