(a) Outside a business or residence district no person shall stop, park, or leave standing any vehicle, whether attended or unattended, upon the roadway when it is practicable to stop, park, or so leave such vehicle off the roadway, but in every event an unobstructed width of the highway opposite a standing vehicle shall be left for the free passage of other vehicles and a clear view of such stopped vehicle shall be available from a distance of 200 feet in each direction upon such highway.

(b) This section, Sections 32-5A-137 and 32-5A-138 shall not apply to the driver of any vehicle which is disabled while on the paved or main-traveled portion of a highway in such manner and to such extent that it is impossible to avoid stopping and temporarily leaving such disabled vehicle in such position. And the provisions of this section, Sections 32-5A-137 and 32-5A-138 shall not apply to any vehicle nor to the driver of any vehicle engaged in the business of carrying passengers for hire and operating over a fixed route and between regular termini operating under the authority of the Interstate Commerce Commission of the United States or under authority of the Alabama Public Service Commission or any federal, state, or municipal authority while stopped on the right-hand side of the highway to pick up or discharge passengers nor to any vehicle nor to the driver thereof engaged in the official delivery of the United States mail when stopped on the right-hand side of the highway for the purpose of picking up or delivering mail, if a clear view of the vehicle may be obtained from a distance of 300 feet in each direction upon such highway. Nothing herein shall be construed to exempt any vehicle from the provisions of Section 32-5-244 and those provisions shall remain applicable to vehicles transporting the United States mail, anything in the section to the contrary notwithstanding.