You ask, "What are the important criteria?

With any technical solution to forklift/operator safety such as yours, I will get interested fast when I see the research report comparing various forklifts under various workplace conditions...with and without the device.

In general, I believe the key criterion is that the device can reliably improve upon operator's precision (safety) and speed on the job. Another criterion might be that at least 90% of the operators using the device could learn to use it to improve their safety and speed on the job.

Best wishes,

Joe M.

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