Except as provided in subsection (g) of this section, this section applies to: Every motor vehicle carrying a passenger for hire; Every school vehicle carrying any passenger; Every bus that is owned or operated by a church and carrying any passenger; Every vehicle carrying as cargo a flammable liquid or an explosive; and Every vehicle carrying hazardous materials of a type and quantity requiring placarding under federal hazardous materials regulations. If the driver of any vehicle described in subsection (a) of this section approaches a railroad grade crossing, the driver shall stop within 50 feet but not less than 15 feet from the nearest rail in the crossing. If the driver of any vehicle described in subsection (a) of this section approaches a railroad grade crossing, the driver, while stopped, shall listen and look in both directions along the track for any approaching or passing railroad train and for any signals indicating the approach or passage of a railroad train. If the driver of any vehicle described in subsection (a) of this section approaches a railroad grade crossing, the driver may not proceed until he can do so safely. If the driver of any vehicle described in subsection (a) of this section approaches a railroad grade crossing, the driver may proceed only in that gear of the vehicle in which it will be unnecessary to shift gears manually while passing through the crossing. If the driver of any vehicle described in subsection (a) of this section approaches a railroad grade crossing, the driver may not shift gears manually while passing over any track of the railroad. This section does not apply to the vehicles described in subsection (a)(1), (4), and (5) of this section, at any railroad grade crossing in a business district or residential district. This section does not apply to school buses and church buses, as described in subsection (a)(2) and (3) of this section, at locations within Baltimore City where complying with the provision of this section would conflict with the existing traffic signal indications. This section does not apply to the vehicles described in subsection (a) of this section, at any railroad grade crossing with an exempt highway–rail grade crossing plaque.