49 CFR § 571.101 - Standard No. 101; Controls and displays.
S2. Purpose. The purpose of this standard is to ensure the accessibility, visibility and recognition of motor vehicle controls, telltales and indicators, and to facilitate the proper selection of controls under daylight and nighttime conditions, in order to reduce the safety hazards caused by the diversion of the driver's attention from the driving task, and by mistakes in selecting controls.
Control means the hand-operated part of a device that enables the driver to change the state or functioning of the vehicle or a vehicle subsystem.
Indicator means a device that shows the magnitude of the physical characteristics that the instrument is designed to sense.
Multi-task display means a display on which more than one message can be shown simultaneously.
Telltale means an optical signal that, when illuminated, indicates the actuation of a device, a correct or improper functioning or condition, or a failure to function.
S5. Requirements. Each passenger car, multipurpose passenger vehicle, truck and bus that is fitted with a control, a telltale or an indicator listed in Table 1 or Table 2 must meet the requirements of this standard for the location, identification, color, and illumination of that control, telltale or indicator. However, the requirements for telltales and indicators do not apply to vehicles with GVWRs of 4,536 kg or greater if these specified vehicles are manufactured before September 1, 2013.
S5.1.2 The telltales and indicators listed in Table 1 and Table 2 and their identification must be located so that, when activated, they are visible to a driver under the conditions of S5.6.1 and S5.6.2.
(a) Is visible to the driver under the conditions of S5.6.1 and S5.6.2,
(b) Identifies the multi-function control with which it is associated graphically or using words,
(c) For multi-task displays with layers, identifies on the top-most layer each system for which control is possible from the associated multi-function control, including systems not otherwise regulated by this standard. Subfunctions of the available systems need not be shown on the top-most layer of the multi-task display, and
(d) Identifies the controls of Table 1 and Table 2 with the identification specified in those tables or otherwise required by this standard, whenever those are the active functions of the multi-function control. For lower levels of multi-task displays with layers, identification is permitted but not required for systems not otherwise regulated by this standard.
(e) Does not display telltales listed in Table 1 or Table 2.
S5.2.1 Except for the Low Tire Pressure Telltale, each control, telltale and indicator that is listed in column 1 of Table 1 or Table 2 must be identified by the symbol specified for it in column 2 or the word or abbreviation specified for it in column 3 of Table 1 or Table 2. If a symbol is used, each symbol provided pursuant to this paragraph must be substantially similar in form to the symbol as it appears in Table 1 or Table 2. If a symbol is used, each symbol provided pursuant to this paragraph must have the proportional dimensional characteristics of the symbol as it appears in Table 1 or Table 2. The Low Tire Pressure Telltale (either the display identifying which tire has low pressure or the display which does not identify which tire has low pressure) shall be identified by the appropriate symbol designated in column 4, or both the symbol in column 4 and the words in column 3. No identification is required for any horn (i.e., audible warning signal) that is activated by a lanyard or by the driver pressing on the center of the face plane of the steering wheel hub; or for a turn signal control that is operated in a plane essentially parallel to the face plane of the steering wheel in its normal driving position and which is located on the left side of the steering column so that it is the control on that side of the column nearest to the steering wheel face plane. However, if identification is provided for a horn control in the center of the face plane of the steering wheel hub, the identifier must meet Table 2 requirements for the horn.
S5.2.3 Supplementary symbols, words, or abbreviations may be used at the manufacturer's discretion in conjunction with any symbol, word, or abbreviation specified in Table 1 or Table 2.
S5.2.6 Except as provided in S5.2.7, all identifications of telltales, indicators and controls listed in Table 1 or Table 2 must appear to the driver to be perceptually upright. A rotating control that has an “off” position shall appear to the driver perceptually upright when the rotating control is in the “off” position.
S5.2.7 The identification of the following items need not appear to the driver to be perceptually upright:
(a) A horn control;
(c) Any rotating control that does not have an “off” position.
S5.2.8 Each control for an automatic vehicle speed system (cruise control) and each control for heating and air conditioning systems must have identification provided for each function of each such system.
S5.2.9 Each control that regulates a system function over a continuous range must have identification provided for the limits of the adjustment range of that function. If color coding is used to identify the limits of the adjustment range of a temperature function, the hot limit must be identified by the color red and the cold limit by the color blue. If the status or limit of a function is shown by a display not adjacent to the control for that function, both the control (unless it is a multi-function control complying with S5.1.4) and the display must be independently identified as to the function of the control, in compliance with S5.2.1, on or adjacent to the control and on or adjacent to the display.
(a) Except as provided in S5.3.1(c), the identifications of controls for which the word “Yes” is specified in column 5 of Table 1 must be capable of being illuminated whenever the headlamps are activated. This requirement does not apply to a control located on the floor, floor console, steering wheel, steering column, or in the area of windshield header, or to a control for a heating and air-conditioning system that does not direct air upon the windshield.
(b) Except as provided in S5.3.1(c), the indicators and their identifications for which the word “Yes” is specified in column 5 of Table 1 must be illuminated whenever the vehicle's propulsion system and headlamps are activated.
(e) A telltale must not emit light except when identifying the malfunction or vehicle condition it is designed to indicate, or during a bulb check.
S22.214.171.124 Means must be provided for illuminating the indicators, identifications of indicators and identifications of controls listed in Table 1 to make them visible to the driver under daylight and nighttime driving conditions.
S126.96.36.199 The means of providing the visibility required by S188.8.131.52:
(a) Must be adjustable to provide at least two levels of brightness;
(c) May be operable manually or automatically; and
(d) May have levels of brightness, other than the two required visible levels of brightness, at which those items and identification are not visible.
(1) If the level of brightness is adjusted by automatic means to a point where those items or their identification are not visible to the driver, means shall be provided to enable the driver to restore visibility.
(b) The means for providing the required visibility may be adjustable manually or automatically, except that the telltales and identification for brakes, highbeams, turn signals, and safety belts may not be adjustable under any driving condition to a level that is invisible.
(1) Light intensity which is manually or automatically adjustable to provide at least two levels of brightness;
(2) A single intensity that is barely discernible to a driver who has adapted to dark ambient roadway conditions;or
(3) A means of being turned off.
S5.4.2 Any indicator or telltale not listed in Table 1 and any identification of that indicator or telltale must not be a color that masks the driver's ability to recognize any telltale, control, or indicator listed in Table 1.
S5.4.3 Each identifier used for the identification of a telltale, control or indicator must be in a color that stands out clearly against the background. However, this requirement does not apply to an identifier for a horn control in the center of the face plane of the steering wheel hub. For vehicles with a GVWR of under 4,536 kg (10,000 pounds), the compliance date for this provision is September 1, 2011. For vehicles with a GVWR of 4,536 kg (10,000 pounds) or over, the compliance date for this provision is September 1, 2013.
S5.5.2 The telltales for any brake system malfunction required by Table 1 to be red, air bag malfunction, low tire pressure, electronic stability control malfunction (as of September 1, 2011), passenger air bag off, high beam, turn signal, and seat belt must not be shown in the same common space.
S5.5.4 Except as provided in S5.5.5, when the underlying conditions exist for actuation of two or more telltales, the messages must be either:
(a) Repeated automatically in sequence, or
(b) Indicated by visible means and capable of being selected for viewing by the driver under the conditions of S5.6.2.
S5.5.5 In the case of the telltale for a brake system malfunction, air bag malfunction, side air bag malfunction, low tire pressure, electronic stability control malfunction (as of September 1, 2011), passenger air bag off, high beam, turn signal, or seat belt that is designed to display in a common space, that telltale must displace any other symbol or message in that common space while the underlying condition for the telltale's activation exists.
(b) Telltales for high beams, turn signal, low tire pressure, and passenger air bag off, and telltales for which the color red is required in Table 1 must not be cancelable while the underlying condition for their activation exists.
S5.6.1 The driver has adapted to the ambient light roadway conditions.