Hi Jim,
We know that NEC is adopted as regulation by states, counties or cities and enforced by electrical inspectors. And there is a effective date for each states, like shown below for NEC 2014.
http://www.electricalcodecoalition.org/ ... tions.aspx

Is there such effective date for NFPA 70E 2015? Recently, at IEEE IAS, the speaker mentioned he will be upgrading his studies to NFPA 70E 2015 next year and I was wondering what is holding him back. Should we adhere to something called AHJ (Authority Having Jurisdiction)?

70E is a "voluntary" standard. It is referenced by NEC in a fine print note so it is not incorporated there.

OSHA does not specify that 70E has to be followed. However it represents an industry consensus safety standard. OSHA has referenced 70E and the general duty clause in enforcement actions with regards to arc flash because by the time enforcement came (2006), arc flash was a known hazard and there were specific industry recommendations for it.

An employer can adopt another standard other than 70E, or even write their own. For example, IEEE C2 (NESC) has its own electrical work standards and arc flash hazard rules. As another example, Canada has their own arc flash standard (although except for annexes and numbering, it is word-for-word identical to 70E). There are many good reasons for doing this, not the least of which is the fact that NESC covers voltages >15 kV and is specifically for generation/transmission/distribution equipment. And as of 2015, OSHA themselves have their own arc flash standard in Subchapter R and 1926 Subchapter V. If an employer were to draft their own standards though they would have the burden of proving that their standards are at least equiivalent which could be a more difficult legal hurdle.

70E is a "voluntary" standard. It is referenced by NEC in a fine print note so it is not incorporated there.

Being a voluntary standard does not prevent jurisdictions from adopting NFPA 70E as a requirement, at least not in Washington State where some City's have taken to enforcing parts of it.

Could you please cite at least one municipality that has enacted NFPA70E, in whole or in part, as part of their municipal code? If you can, who enforces the code?

Washington (State) Cities Code, Page 48:
Link: http://www.mybuildingpermit.com/Misc/WA%20Cities%20Elect%20Code%2011-12-09.pdf

The section cited deals with the application of a label which provides incident energy levels (i.e. arc flash information).
There is nothing in that section that requires NFPA70E to be used when determining the data for the labels, which is good as most power systems study calculations are performed using IEEE1584 and not NFPA70E.

Section 80.5 does not even mention NFPA70E as one of the included standards.
Section 85.5 does not explicitly mention the 'actual performance or work tasks' ala OSHA, but rather focuses on the installed material.