Is it permissible to take a commission from self-employed drivers for assigning transportation tasks to them, without the knowledge of the employer or even with their knowledge, considering that I am an employee and receive a salary for my work?

It is not permissible to take a commission from drivers, whether with or without the knowledge of the company owner, because that is an usurpation of the employer's right, and there is no legitimate justification for taking a commission from the worker in this manner.