They look like a good idea. Bear in mind that you can't have a red light shining forwards if you're on a public road (note the broad definition I already pasted above). https://www.nzta.govt.nz/resources/rules/vehicle-lighting-2004/ - section 2.1 (16). I'm not sure how your FLT WoF will work if you have non-standard lights because testing officers have been known to fail cars that have halogen lights that have just a slightly blue hue (of course, this isn't relevant if you're only using it in a closed yard or warehouse). You could always turn them off if you have to drive them on the road, as per Phil's suggestion.

This could be extremely dangerous. When the vehicle is immobilised, does it retain power steering control and brakes? It could cause a huge accident.

Something went wrong with the link in the last post: https://www.drivingtests.co.nz/roadcode-questions/car/core/whats-the-legal-definition-of-a-road/

I'm pretty sure you can't have blue flashing lights on a vehicle if it's driven on a road - http://www.police.govt.nz/faq/is-it-true-that-only-emergency-vehicles-can-use-red-and-blue-flashing-lights . The definition of a road is very broad - <a href="https://www.drivingtests.co.nz/roadcode-questions/car/core/whats-the-legal-definition-of-a-road/" target="_blank" rel="nofollow">https://www.drivingtests.co.nz/roadcode-questions/car/core/whats-the-legal-definition-of-a-road/</a>
So, if they're just used in a warehouse blue lights would be fine, but you wouldn't be able to use them in a right-of-way, public car park, footpath or road. Why aren't the using the standard orange flashing lights which are the usually hazard warning beacons?

I'm Darren and I've run https://www.drivingtests.co.nz since 2010. My areas of interest are vehicle and transport safety and training.