Formula E rule makers have taken a harder stance on mid-season driver changes for the second year of the all-electric championship, with only two changes per car each season allowed.

During the inaugural season teams were permitted to make any number of driver changes, with a total of 35 drivers competing in at least one Formula ePrix during the 2014/15 season on a grid consisting of 20 cars. Andretti Formula E were the most frequent driver changers with five different names on the #28 car over the course of last season.

Formula E has added a restriction to ensure a maximum of just two driver changes per car for the 2015/16 season, citing the reason to avoid 'potential conflict in the fight for the championship'.

The rule makers have also clarified that in the event of a force majeure and a driver is unavailable due to unforeseen circumstances a change may be permitted with approval from the race stewards.

Any driver changes will also need be announced two weeks prior to the event to enable fans to vote for the full grid entry on the Fan Boost system.

In addition to the rule change, all Formula E drivers will only be allowed to race with a new e-Licence which has become a mandatory requirement. To come in line with the F1 Super Licence, drivers must accumulate 20 points or more in the past three seasons to be allowed to race in Formula E.

However, if a driver is judged by the FIA to demonstrate 'outstanding ability' in single-seater formula cars but has no opportunity to qualify under the requirements above, they can still obtain an e-Licence with an appeal to the governing body.