(a) No common carrier by motor vehicle subject to the provisions of this chapter shall engage in intrastate commerce on any highway in this state unless there is in force with respect to such carrier a certificate of public convenience and necessity issued by the commission pursuant to the provisions of this chapter authorizing such operation. The application for such certificate shall be decided in accordance with the procedure provided in Section 37-3-11, and such certificate shall be issued or denied accordingly. No common carrier of passengers holding a certificate of public convenience and necessity issued to it by the commission shall be required to apply for a certificate under this chapter, but such certificate held and effective shall be effective as if issued under this chapter, but this shall not be construed or held to relieve the holder of such certificate from complying with all other provisions of this chapter and any and all laws now or hereafter in effect.

(b) Application for certificates shall be made in writing to the commission, be verified under oath and shall be in such form and contain such information and be accompanied by proof of service of notice thereof upon such interested parties as the commission shall, by regulation, require; provided, that the commission shall give notice of the filing of any such application upon the State Department of Transportation and, in the case of an application for a certificate to transport passengers, upon each common carrier of passengers then operating or proposing to operate by application pending before the commission in the territory proposed to be served; and, in the case of an application for a certificate to transport freight, upon each common carrier of freight then operating or proposing to operate by application pending before the commission in the territory proposed to be served.