OAR 735-124-0120
Brakes
(1)
Four-wheel hydraulic brakes adequate to control the vehicle at all times when fully loaded and traveling at maximum speeds shall be provided unless the vehicle is equipped with a brake system of a superior type as approved by Transportation Safety.(2)
Auxiliary or emergency brake shall be provided in addition to service brake and shall be an entirely separate, mechanically operated device. It shall be adequate to hold vehicle stationary when fully loaded on any grade upon which vehicle may be operated.(3)
All new buses placed in service on and after the effective date of this Safety Code, the chassis of which is designed for any bus body of 36 or more workers, shall be equipped with full compressed air brakes, vacuum-actuated power or assistor type brakes, or compressed air-over-hydraulic brakes.(a)
Such installation shall be made by authorized representatives of chassis or brake manufacturer and shall conform to recommendation of that manufacturer.(b)
Hydraulic line pressure shall not exceed recommendation of chassis or brake manufacturer.(c)
Reservoir capacity shall be at least 1650 cubic inches for full compressed air systems, and at least 1000 cubic inches for vacuum-actuated systems and for compressed air-over-hydraulic system.(d)
Vehicles having full compressed air systems shall be equipped with:(A)
A safety valve mounted on first reservoir to protect air brake system against excessive air pressure and check valve located between source of supply and reservoir.(B)
Air gauge mounted on instrument panel to register air pressure in air brake system.(C)
Visible or audible low pressure indicator to warn driver if air pressure in air brake system falls below 60 pounds per square inch.(e)
Vehicles having vacuum-actuated or compressed air-over-hydraulic systems shall be equipped with check valve located between source of supply and reservoir.
Source:
Rule 735-124-0120 — Brakes, https://secure.sos.state.or.us/oard/view.action?ruleNumber=735-124-0120.