Not a safe practice to drive with forks elevated....an explanation of how the 3 point suspension work in the 'Stability Triangle' will make sense to a thinking person who understands that the center of gravity is constantly moving within that 'safe' area. Adding extra pull from travelling with weight of the forks[ 500 lbs] elevated will tend to make the center of gravity move outside the stability triangle and tip the truck over.

as was said in an earlier post some lifts do have a speed limiting switch on the mast that limits the travel speed when elevated above a predetermined height. Not all lifts are equipt with this option though so by general rule and is taught in every training class given to operators, you should ALWAYS travel with the forks only a couple of inches off the ground at all times, especially when carrying a load. The ONLY time you would be moving the lift is if you are putting your load/product on an elevated shelf and only doing it during that process of inserting it into the storage spot or removing it. You always insure once you have the load on the forks you should always bring it straight down to the floor, or wait to the last instance to raise it, at your first available opportunity to avoid instability factors which are very high when the forks are elevated to a height above the top of the mast.
If you are fully elevated always minimize the amount of traveling you have to do no matter what the situation is.
Note: if a lift has a travel speed limit switch on it then it has to be operational by law, no exceptions, if you find one bypassed that is a huge violation and big fines could be given to the company if not repaired and found this way.

Does this unit have limit switches on the mast to reduce speed when traveling while elevated? Most ele. units are set up this way.If so then he is right. If not check the data tag on the unit and see if any down rating info is on the tag that reflects any data for traveling / weight / height info. Fork length can also play a factor in speed/ height operations. Does your company set policy concerning this issue, if not you need to have a set policy in writing (black and white) to protect your self in case of an accident. Just let some law firm get a hold of this one. I have done my share of accident investigations and with no set in place policy in writing this can turn into a very expensive can of worms. The excuse is going to be that is how i always did it.

As I say to anyone I have the pleasure of instructing, be they a novice or an experienced operator:
Seat belts are not designed to prevent injury but are designed to prevent serious injury in cases of an accident.
As for turning with an elevated load and at speed......

That is a textbook example of a Preventable Accident.

Be careful!

Well spoken

Even though the original post is from 2019, it is good to see people are still making comments on what is a serious issue.
As has been said by many, there is no "legally defined" height and the common "norm" when training is generally the forks between 4 - 6 inches from the ground and tilted backwards.
Here in the UK, it is one of the questions you can be asked as part of the Theory Test:
When driving an unladen lift truck how should the forks be set?
The answer is: As low as practicable and tilted back
But as many have said, it comes down to the initial training and then the management on-site to enforce good practice.

since your own internal training states a set height that should be all you need that person is in violation of your company policy I don't know how your company handles things like this but most i have worked with gives 3 written warnings and then termination. some companies policy states any safety violation is termination on the spot. Good luck

You need to fire that idiot !

That is a serious safety violation, plus very very dumb thing to do with any machine that uses forks.

Travelling at height is a safety breach, end of the story. The company policies and procedures and training manual should state this clearly. If a person is breaking those rules in relation to safety, they should be instantly dismissed. Nobody, you, me the boss or owner of the company or that eejit clown, fool dope has no right, whatsoever to put everyone else in danger. Go through the proper channels and show others that the company is serious in relation to the safety of the employees.

From some accidents in the past if the forks are over 4 and you hit a person with the fork it could cut the main artery and causing death below 4 it may just be ankle or foot damage and the person 99% of the time lives through it its much easier to follow directions than kill someone

The OSHA standard requires ("shall") operator training and further requires that the training includes the "Operating Instructions" (i.e. the Operator Manual that comes with the truck). I would look there first for instructions on how high to carry a load while traveling:

OSHA 1910.178(l)(3)
Training program content. Powered industrial truck operators shall receive initial training in the following topics, except in topics which the employer can demonstrate are not applicable to safe operation of the truck in the employer's workplace.
Truck-related topics:
1910.178(l)(3)(i)(A)
Operating instructions, warnings, and precautions for the types of truck the operator will be authorized to operate;

ANSI/ITSDF B56.1 (which OSHA requires conformance to) further states:

5.3.10 Travel with load-engaging means or load low and, where possible, tilted back. Do not elevate the load except during stacking.

and

5.3.18.(c)/5.3.22(c) - Tipping forward can occur and its likelihood is increased under the following conditions, or combination of them:
(2) traveling with the load tilted forward and/or elevated

and

5.3.22.(b) - The likelihood of lateral tipover is increased under any of the following conditions, or combinations of them
(2) traveling with the load or load handling mechanism elevated

Are there any safety programing that will slow a standup down when the forks are fully extended? We had had two accidents, one flip over and one taking out overhead camera, These are brand new Clark lifts. Can they be slowed down with forks up?

Another problem that can happen while driving with the forks up high is if they hit something up there, while moving, the leverage is so great that it will want to tip the machine over, especially going backwards.