(a) In General. - The Secretary shall register, subject to section 13906(b), a person to be a broker for transportation of property subject to jurisdiction under subchapter I of chapter 135, if the Secretary finds that the person is fit, willing, and able to be a broker for transportation and to comply with this part and applicable regulations of the Secretary. (b) Registration as Carrier Required. - (1) In general. - The broker may provide the transportation itself only if the broker also has been registered to provide the transportation as a motor carrier under this chapter. (2) Limitation. - This subsection does not apply to a motor carrier registered under this chapter or to an employee or agent of the motor carrier to the extent the transportation is to be provided entirely by the motor carrier, with other registered motor carriers, or with rail or water carriers. (c) Regulations To Protect Shippers. - Regulations of the Secretary applicable to brokers registered under this section shall provide for the protection of shippers by motor vehicle. (d) Bond and Insurance. - The Secretary may impose on brokers for motor carriers of passengers such requirements for bonds or insurance or both as the Secretary determines are needed to protect passengers and carriers dealing with such brokers.