There are several ranges for head movement. For cervical spine, typical, healthy ROM for lateral rotation is 80-90 degrees, extension is 60 degrees, flexion is 45 degrees to each side  and lateral flexion 20-45 degrees with head in neutral position. I believe that you are looking at lateral rotation. 

Thank you Babulal for your informative answer. But, what is the safe  view range of driver which can keep driver focus on road.

regards

During driving this can be an average of about 35 degrees (left lateral rotation) and 43 degrees (right lateral rotation). See first reference below. This should be similar for driving on the right of left side of the road where it differs based on country. The ROM will be different for backing up or reversing a vehicle. The second reference below has that information if you need it. Hope this helps.

Shugg, J. A., Jackson, C. D., & Dickey, J. P. (2011). Cervical spine rotation and range of motion: pilot measurements during driving. Traffic injury prevention, 12(1), 82-87.

Bible, J. E., Biswas, D., Miller, C. P., Whang, P. G., & Grauer, J. N. (2010). Normal functional range of motion of the cervical spine during 15 activities of daily living. Journal of spinal disorders & techniques, 23(1), 15-21.

It is a very good question. I have been treating tremors for 40 years.

I have never thinking about the head tremor. It is the reality that  the head tremor can decrease the sharp of the vision during driving. It is important becasue of driving licence. I haven't heard about that it is included in the driving licence. However, there are few cases with essential tremor on head which may deceision about it

Best,

Judit MÁlly

Many thanks Babulal for your time and assistance .Very good references. But, I can''t download the full text, I only read them online.

Thank again

Regards

Many thanks Judit MÁlly to share us your experience. Hope to full health.

I hope we can share our ideas to get good view ans solution about this issue.

Regards