Text of Draft Revised Guidelines

PART 1192 -- AMERICANS WITH DISABILITIES ACT (ADA) ACCESSIBILITY

GUIDELINES FOR TRANSPORTATION VEHICLES

Subpart A -- General
Sec.
1192.1 Purpose.
1192.2 Equivalent facilitation.
1192.3 Definitions.
1192.4 Miscellaneous instructions.

Subpart B -- Buses, Vans and Similar Vehicles
1192.21 General.
1192.23 Mobility aid accessibility.
1192.25 Doors, steps and thresholds.
1192.27 Priority seating signs.
1192.29 Interior circulation, handrails and stanchions.
1192.31 Lighting.
1192.33 Fare box.
1192.35 Public information system.
1192.37 Stop request.
1192.39 Destination and route signs.

Subpart A -- General

1192.1 Purpose.

This part provides minimum guidelines and requirements for accessibility standards to be issued by the Department of Transportation in 49 CFR part 38 for transportation vehicles required to be accessible by the Americans with Disabilities Act (ADA) of 1990, 42 U.S.C. 12101 et seq.

1192.2 Equivalent facilitation.

Departures from particular technical and scoping requirements of these guidelines by use of other designs and technologies are permitted where the alternative designs and technologies used will provide substantially equivalent or greater access to and usability of the vehicle. Departures are to be considered on a case-by-case basis by the Department of Transportation under the procedure set forth in 49 CFR 37.7.

1192.3 Definitions.

Accessible means, with respect to vehicles covered by this part, compliance with the provisions of this part.

Bridgeplate means a short plate or ramp designed to bridge a horizontal or vertical gap between a vehicle floor and a boarding area.

Bus means any of several types of self-propelled vehicles, other than an over-the-road bus, generally rubber tired, intended for use on city streets, highways, and busways, including but not limited to minibuses, forty- and thirty-foot transit buses, articulated buses, double-deck buses, and electric powered trolley buses, used to provide designated or specified public transportation services. Self-propelled, rubber tire vehicles designed to look like antique or vintage trolleys or street cars are considered buses.

Demand responsive system means any system of transporting individuals, including the provision of designated public transportation service by public entities and the provision of transportation service by private entities, including but not limited to specified public transportation service, which is not a fixed route system.

Designated public transportation means transportation provided by a public entity (other than public school transportation) by bus, rail, or other conveyance (other than transportation by aircraft or intercity or commuter rail transportation) that provides the general public with general or special service, including charter service, on a regular and continuing basis.

Fixed route system means a system of transporting individuals (other than by aircraft), including the provision of designated public transportation service by public entities and the provision of transportation service by private entities, including but not limited to specified public transportation service, on which a vehicle is operated along a prescribed route according to a fixed schedule or having a general frequency or headway, which may vary according to time of day.

New vehicle means a vehicle which is offered for sale or lease after manufacture without any prior use.

Remanufactured vehicle means a vehicle which has been structurally restored and has had new or rebuilt major components installed to extend its service life.

Specified public transportation means transportation by bus, rail, or any other conveyance (other than aircraft) provided by a private entity to the general public, with general or special service (including charter service) on a regular and continuing basis.

Used vehicle means a vehicle with prior use.

1192.4 Miscellaneous instructions.

(a) Dimensional conventions. Dimensions that are not noted as minimum or maximum are absolute.

(b) Dimensional tolerances. All dimensions are subject to conventional engineering tolerances for material properties and field conditions, including normal anticipated wear not exceeding accepted industry-wide standards and practices.

(c) General terminology. The terms used in this part shall have the following meanings:

(1) “Comply with” means meet one or more specification of these guidelines.

(2) “Where, where provided, when” denotes a specification that applies only when the conditions described are present.

(3) “May” denotes an option or alternative.

(4) “Shall” denotes a mandatory specification or requirement.

(5) “Should” denotes an advisory specification or recommendation and is used only in the advisory notes to this part.

Subpart B -- Buses, Vans and Similar Vehicles

1192.21 General.

(a) New, used or remanufactured buses, vans and similar vehicles (except over-the-road buses covered by subpart G of this part), to be considered accessible by regulations issued by the Department of Transportation in 49 CFR part 37, shall comply with the applicable provisions of this subpart.

(b) If portions of a vehicle are modified in a way that affects or could affect accessibility, each such portion shall comply, to the maximum extent feasible, with the applicable provisions of this subpart. This provision does not require that inaccessible buses be retrofitted with lifts, ramps or other boarding devices.

(c) Vehicles shall provide an unobstructed volume, from the level change or boarding device to the securement locations, 30 inches wide minimum by 48 inches long minimum by 40 inches high minimum, plus additional space as may be required by sections 23(a)(2), 23(d)(2) and 25(c). A vehicle shall not be required to be designed or modified to accommodate wheelchairs and mobility aids which exceed these dimensions or which weigh more than 660 pounds when occupied.

(d) If stations or stops are constructed to provide a boarding and alighting area at the vehicle floor height, the boarding and alighting area shall comply with 810.5.1, 810.5.2, 810.6, 810.7 and 810.8 of Appendix D of 36 CFR part 1191. If stations or stops are constructed to provide a boarding and alighting area on a sidewalk or road shoulder, the boarding and alighting area shall comply with 810.2, 810.3 and 810.4 of the Appendix D of 36 CFR part 1191. If construction is carried out by an entity other than the transportation provider, compliance with the above sections shall be to the extent that the transportation provider has control of, or can exert influence over, the design and construction of boarding and alighting areas.

1192.23 Mobility aid accessibility.

(a) General. Vehicles covered by this subpart shall provide the following:

(1) A level-change mechanism or boarding device (e.g., lift, bridgeplate or ramp) complying with paragraph (b) or (c) of this section at all doors intended for use by persons using wheelchairs or mobility aids wherever the separation between vehicle floor and boarding and alighting area exceeds either 2 inches horizontally or 5/8 inch vertically.

(2) Sufficient clearances to permit a wheelchair or other mobility aid user to reach securement locations. At least one route to each securement location shall have a clear width of 36 inches minimum, measured from floor level to a height of 40 inches, and a clear width of 30 inches above a height of 40 inches. Where a turn is required, sufficient maneuvering space shall be provided to allow a wheelchair or mobility aid having a width of 30 inches maximum and a length of 48 inches maximum to turn with a minimum of back-and-forth movement.

(3) At least two securement locations and devices, complying with paragraph (d) of this section on vehicles in excess of 22 feet in length and at least one securement location and device complying with paragraph (d) of this section on vehicles 22 feet in length or less.

(b) Vehicle lift.

(1) Design load. The design load of the lift shall be at least 660 pounds. Working parts, such as cables, pulleys, and shafts, which can be expected to wear, and upon which the lift depends for support of the load, shall have a safety factor of at least six, based on the ultimate strength of the material. Nonworking parts, such as platform, frame, and attachment hardware which would not be expected to wear, shall have a safety factor of at least three, based on the ultimate strength of the material.

(2) Controls.
(i) Requirements. The controls shall be interlocked with the vehicle brakes, transmission, or door, or shall provide other appropriate mechanisms or systems, to ensure that the vehicle cannot be moved when the lift is not stowed and that the lift cannot be deployed unless the interlocks or systems are engaged so that the vehicle cannot be moved. The lift shall deploy to all levels (i.e., roadway, curb, and intermediate positions) normally encountered in the operating environment. Where provided, each control for deploying, lowering, raising, and stowing the lift and lowering the roll-off barrier shall be of a momentary contact type requiring continuous manual pressure by the operator and shall not allow improper lift sequencing when the lift platform is occupied. The controls shall allow reversal of the lift operation sequence, such as raising or lowering a platform that is part way down, without allowing an occupied platform to fold or retract into the stowed position.
(ii) Exception. Where the lift is designed to deploy with its long dimension parallel to the vehicle axis and which pivots into or out of the vehicle while occupied (i.e., "rotary lift"), the requirements of this paragraph prohibiting the lift from being stowed while occupied shall not apply if the stowed position is within the passenger compartment and the lift is intended to be stowed while occupied.

(3) Emergency operation. The lift shall incorporate an emergency method of deploying, lowering to ground level with a lift occupant, and raising and stowing the empty lift if the power to the lift fails. No emergency method, manual or otherwise, shall be capable of being operated in a manner that could be hazardous to the lift occupant or to the operator when operated according to manufacturer's instructions, and shall not permit the platform to be stowed or folded when occupied, unless the lift is a rotary lift and is intended to be stowed while occupied.

(4) Power or equipment failure. Platforms stowed in a vertical position, and deployed platforms when occupied, shall have provisions to prevent their deploying, falling, or folding any faster than 12 inches/second or their dropping of an occupant in the event of a single failure of any load carrying component.

(5) Platform barriers. The lift platform shall be equipped with barriers to prevent any of the wheels of a wheelchair or mobility aid from rolling off the platform during its operation. A movable barrier or inherent design feature shall prevent a wheelchair or mobility aid from rolling off the edge closest to the vehicle until the platform is in its fully raised position. Each side of the lift platform which extends beyond the vehicle in its raised position shall have a barrier a minimum 1 1/2 inches high. Such barriers shall not interfere with maneuvering into or out of the aisle. The loading-edge barrier (outer barrier) which functions as a loading ramp when the lift is at a boarding and alighting area level, shall be sufficient when raised or closed, or a supplementary system shall be provided, to prevent a power wheelchair or mobility aid from riding over or defeating it. The outer barrier of the lift shall automatically raise or close, or a supplementary system shall automatically engage, and remain raised, closed, or engaged at all times that the platform is more than 3 inches above the roadway or boarding and alighting area and the platform is occupied. Alternatively, a barrier or system may be raised, lowered, opened, closed, engaged, or disengaged by the lift operator, provided an interlock or inherent design feature prevents the lift from rising unless the barrier is raised or closed or the supplementary system is engaged.

(6) Platform surface. The platform surface shall be free of any protrusions over 1/4 inch high and shall be slip resistant. The platform shall have a minimum clear width of 28 1/2 inches at the platform, a minimum clear width of 30 inches measured from 2 inches above the platform surface to a height of 40 inches above the platform, and a minimum clear length of 48 inches measured from 2 inches above the surface of the platform to a height of 40 inches above the surface of the platform. (See Fig. 1)

(7) Platform gaps. Any openings between the platform surface and the raised barriers shall not permit a sphere with a diameter of 5/8 inch to pass through. When the platform is at vehicle floor height with the inner barrier (if applicable) down or retracted, gaps between the forward lift platform edge and the vehicle floor shall not exceed 1/2 inch horizontally and 5/8 inch vertically. Platforms on semi-automatic lifts may have a hand hold not exceeding 1 1/2 inches by 4 1/2 inches located between the edge barriers.

(8) Platform entrance ramp. The entrance ramp, or loading-edge barrier used as a ramp, shall not exceed a slope of 1:8, measured on level ground, for a maximum rise of 3 inches, and the transition from roadway or boarding and alighting area to ramp may be vertical without edge treatment up to 1/4 inch. Thresholds between 1/4 inch and 1/2 inch high shall be beveled with a slope no greater than 1:2.

(9) Platform deflection. The lift platform (not including the entrance ramp) shall not deflect more than 3 degrees (exclusive of vehicle roll or pitch) in any direction between its unloaded position and its position when loaded with 660 pounds applied through a 26 inch by 26 inch test pallet at the centroid of the platform.

(10) Platform movement. No part of the platform shall move at a rate exceeding 6 inches/second during lowering and lifting an occupant, and shall not exceed 12 inches/second during deploying or stowing. This requirement does not apply to the deployment or stowage cycles of lifts that are manually deployed or stowed. The maximum platform horizontal and vertical acceleration when occupied shall be 0.3g.

(11) Boarding direction. The lift shall permit both inboard and outboard facing of wheelchair and mobility aid users.

(12) Use by standees. Lifts shall accommodate persons using walkers, crutches, canes or braces or who otherwise have difficulty using steps. The platform may be marked to indicate a preferred standing position.

(13) Handrails. Platforms on lifts shall be equipped with handrails on two sides, which move in tandem with the lift, and which shall be graspable and provide support to standees throughout the entire lift operation. Handrails shall have a usable component at least 8 inches long with the lowest portion a minimum 30 inches above the platform and the highest portion a maximum 38 inches above the platform. The handrails shall be capable of withstanding a force of 100 pounds concentrated at any point on the handrail without permanent deformation of the rail or its supporting structure. The handrail shall have a cross-sectional diameter between 1 1/4 inches and 2 inches or shall provide an equivalent grasping surface, and have eased edges with corner radii of not less than 1/8 inch. Handrails shall be placed to provide a minimum 1 1/2 inches knuckle clearance from the nearest adjacent surface. Handrails shall not interfere with wheelchair or mobility aid maneuverability when entering or leaving the vehicle.

(c) Vehicle ramps and bridgeplates.

(1) Design load. Ramps and bridgeplates 30 inches or longer shall support a load of 660 pounds, placed at the centroid of the ramp or bridgeplate distributed over an area of 26 inches by 26 inches, with a safety factor of at least 3 based on the ultimate strength of the material. Ramps or bridgeplates shorter than 30 inches shall support a load of 330 pounds. Folding or telescoping ramps are permitted provided they meet all structural requirements of this section.

(2) Surface. The surface of ramps and bridgeplates shall be slip resistant, continuous from edge to edge, and shall not have protrusions from the surface greater than 1/4 inch high. Ramps and bridgeplates shall have a clear width of 30 inches.

(3) Threshold. The transition from boarding and alighting areas to ramps and bridgeplates and the transition from vehicle floor to ramps and bridgeplates may be vertical without edge treatment up to 1/4 inch. Changes in level between 1/4 inch and 1/2 inch shall be beveled with a slope no greater than 1:2.

(4) Barriers. Each side of ramps and bridgeplates shall have barriers at least 2 inches high along all portions of ramps and bridgeplates more than 3 inches above the boarding and alighting surface.

(5) Slope. The slope of all ramps and bridgeplates shall not exceed 1:8. Only one device shall be required to have a maximum slope of 1:8 when deployed to roadway, provided all required securement locations are connected to it by a route complying with (a)(2). All other devices shall not exceed a slope of 1:8 when deployed to the intended boarding and alighting areas.

(6) Attachment. When in use for boarding or alighting, ramps and bridgeplates shall be firmly attached to the vehicle so that they are not subject to displacement when in use and that no gap between vehicle and ramp permits the passage of a sphere having a diameter of 5/8 inch.

(7) Stowage. A compartment, securement system, or other appropriate method shall be provided to ensure that stowed ramps and bridgeplates, including portable ramps and bridgeplates stowed in the passenger area, do not impinge on a passenger's wheelchair or mobility aid or pose any hazard to passengers in the event of a sudden stop or maneuver.

(8) Handrails. If provided, handrails shall allow persons with disabilities to grasp them from outside the vehicle while starting to board, and to continue to use them throughout the boarding process, and shall have the top between 30 inches and 38 inches above the ramp or bridgeplate surface. The handrails shall be capable of withstanding a force of 100 pounds concentrated at any point on the handrail without permanent deformation of the rail or its supporting structure. The handrail shall have a cross-sectional diameter of 1 1/4 inches minimum to 2 inches maximum or shall provide an equivalent grasping surface, and have eased edges with corner radii of not less than 1/8 inch. Handrails shall not interfere with wheelchair or mobility aid maneuverability when
entering or leaving the vehicle.

(9) Operation. Power operated ramps and bridgeplates shall be deployable manually.

(d) Securement devices.

(1) Design load. Securement systems on vehicles with GVWRs of 30,000 pounds or above, and their attachments to such vehicles, shall restrain a force in the forward longitudinal direction of up to 2,000 pounds per securement leg or clamping mechanism and a minimum of 4,000 pounds for each mobility aid. Securement systems on vehicles with GVWRs of up to 30,000 pounds, and their attachments to such vehicles, shall restrain a force in the forward longitudinal direction of up to 2,500 pounds per securement leg or clamping mechanism and a minimum of 5,000 pounds for each mobility aid.

(2) Location and size. The securement system shall be placed as near to the accessible entrance as practicable and shall have a clear floor area of 30 inches minimum by 48 inches minimum. One full unobstructed side of the clear floor area shall adjoin or overlap an access route. If a clear floor area is located in a bay or otherwise confined on all or part of three sides, additional maneuvering clearances shall be provided in accordance with the following:
(i) Forward Approach. Bays shall be 36 inches (915 mm) wide minimum where the depth exceeds 24 inches (610 mm). See figure 1.
(ii) Parallel Approach. Bays shall be 60 inches (1525 mm) wide minimum where the depth exceeds 15 inches (380 mm). See figure 2.
Securement areas may have fold-down seats to accommodate other passengers when a wheelchair or mobility aid is not occupying the area, provided the seats, when folded up, do not obstruct the clear floor space required.

Figure 1 shows in plan view a wheelchair space 36 inches wide minimum in an alcove deeper than 24 inches.  Figure 2 shows in plan view a wheelchair space entered from the side that is 60 inches long minimum and located in a recess deeper that 15 inches.

(3) Mobility aids accommodated. The securement system shall secure wheelchairs and mobility aids which can enter and maneuver within a vehicle complying with this subpart and shall either be automatic or easily attached by a person familiar with the system and mobility aid and having average dexterity.

(4) Orientation. In vehicles in excess of 22 feet in length, at least one securement device or system required by paragraph (a)(3) shall secure the wheelchair or mobility aid facing toward the front of the vehicle. In vehicles 22 feet in length or less, the required securement device shall secure the wheelchair or mobility aid either facing toward the front of the vehicle or rearward. Additional securement devices or systems shall secure the wheelchair or mobility aid facing forward or rearward. Where the wheelchair or mobility aid is secured facing the rear of the vehicle, a padded barrier shall be provided The padded barrier shall extend from a height of 38 inches from the vehicle floor to a height of 56 inches from the vehicle floor with a width of 10 inches minimum to 12 inches maximum, laterally centered immediately in back of the seated individual. Such barriers need not be solid provided equivalent protection is afforded.

(5) Movement. When the wheelchair or mobility aid is secured in accordance with manufacturer’s instructions, the securement system shall limit the movement of an occupied wheelchair or mobility aid to no more than 2 inches in any direction under normal vehicle operating conditions.

(6) Stowage. When not being used for securement, or when the securement area can be used by standees, the securement system shall not protrude into the required clear floor area, interfere with passenger movement, shall not present any hazardous condition, shall be reasonably protected from vandalism, and shall be readily accessed when needed for use.

(7) Seat belt and shoulder harness. For each wheelchair or mobility aid securement device provided, a passenger seat belt and shoulder harness, complying with all applicable provisions of 49 CFR part 571, shall also be provided for use by wheelchair or mobility aid users. Such seat belts and shoulder harnesses shall not be used in lieu of a device which secures the wheelchair or mobility aid itself.

1192.25 Doors, steps and thresholds.

(a) Slip resistance. All aisles, steps, floor areas where people walk and floors in securement locations shall have slip-resistant surfaces.

(b) Contrast. All step edges, thresholds, and the boarding edge of ramps or lift platforms shall have a band of color(s) running the full width of the step or edge which contrasts from the step tread and riser, or lift, ramp or bridgeplate surface, either light-on-dark or dark-on-light.

(c) Door height. For vehicles in excess of 22 feet in length, the vertical clearance between the top of the door opening and the raised lift platform, or highest point of a ramp, shall be a minimum of 68 inches. For vehicles of 22 feet in length or less, the vertical clearance shall be a minimum of 56 inches from the vehicle entrance to the securement location.

1192.27 Priority seating signs.

(a) Each vehicle shall contain sign(s) which indicate that seats in the front of the vehicle are priority seats for persons with disabilities, and that other passengers should make such seats available to those who wish to use them. At least one set of forward-facing seats shall be so designated.

(b) Each securement location shall have a sign designating it as such.

(c) Characters on signs required by paragraphs (a) and (b) of this section shall comply with the following:

(1) Proportions. Characters shall be selected from fonts where the width of the uppercase letter "O" is 55 percent minimum and 110 percent maximum of the height of the uppercase letter "I".

(2) Height. Where the height of the characters is 40 inches to 70 inches above the floor, the minimum character height shall be 5/8 inch. Where the characters are more than 70 inches above the floor, the minimum character height shall be 2 inches.

(3) Stroke thickness. Stroke thickness of the uppercase letter "I" shall be 10 percent minimum and 30 percent maximum of the height of the character.

(4) Character spacing. Character spacing shall be measured between the two closest points of adjacent characters, excluding word spaces. Spacing between individual characters shall be 10 percent minimum and 35 percent maximum of character height.

(5) Line spacing. Spacing between the baselines of separate lines of characters within a message shall be 135 percent minimum and 170 percent maximum of the character height.

(6) Contrast. Characters shall contrast with their background with either light characters on a dark background or dark characters on a light background.

1192.29 Interior circulation, handrails and stanchions.

(a) Interior handrails and stanchions shall permit sufficient turning and maneuvering space for wheelchairs and other mobility aids to reach a securement location from the lift, bridgeplate or ramp.

(b) Handrails and stanchions shall be provided in the entrance to the vehicle in a configuration which allows persons with disabilities to grasp such assists from outside the vehicle while starting to board, and to continue using such assists throughout the boarding and fare collection process. Handrails shall have a cross-sectional diameter of 1 1/4 inches minimum to 2 inches maximum or shall provide an equivalent grasping surface, and have eased edges with corner radii of not less than 1/8 inch. Handrails shall be placed to provide a minimum 1 1/2 inches knuckle clearance from the nearest adjacent surface. Where on-board fare collection devices are used on vehicles in excess of 22 feet in length, a horizontal passenger assist shall be located across the front of the vehicle and shall prevent passengers from sustaining injuries on the fare collection device or windshield in the event of a sudden deceleration. Without restricting the vestibule space, the assist shall provide support for a boarding passenger from the front door through the boarding procedure. Passengers shall be able to lean against the assist for security while paying fares.

(c) For vehicles in excess of 22 feet in length, handholds shall be provided adjacent to the aisle on the back of each forward or rear facing seat.

(d) Handrails and stanchions shall be sufficient to permit safe boarding, on-board circulation, seating and standing assistance, and alighting by persons with disabilities.

(e) For vehicles in excess of 22 feet in length with front-door lifts, bridgeplates or ramps, vertical stanchions immediately behind the driver shall either terminate at the lower edge of the aisle-facing seats, if applicable, or be "dog-legged" so that the floor attachment does not impede or interfere with wheelchair footrests. If the driver seat platform must be passed by a wheelchair or mobility aid user entering the vehicle, the platform, to the maximum extent practicable, shall not extend into the aisle or vestibule beyond the wheel housing.

(f) For vehicles in excess of 22 feet in length, the minimum interior height along the path from the lift, ramp or bridgeplate to the securement location shall be 68 inches. For vehicles of 22 feet in length or less, the minimum interior height from lift to securement location shall be 56 inches.

1192.31 Lighting.

(a) A stepwell or doorway immediately adjacent to the driver shall have, when the door is open, at least 2 foot-candles of illumination measured on the step tread or lift platform.

(b) Other stepwells and doorways, including doorways in which lifts, bridgeplates or ramps are installed, shall have, at all times, at least 2 foot-candles of illumination measured on the step tread, or lift, bridgeplate or ramp, when deployed at the vehicle floor level.

(c) The vehicle doorways, including doorways in which lifts, bridgeplates or ramps are installed, shall have outside light(s) which, when the door is open, provide at least 1 foot-candle of illumination on the street surface for a distance of 3 feet perpendicular to all points on the bottom step tread outer edge. Such light(s) shall be shielded to protect the eyes of entering and exiting passengers.

1192.33 Fare box.

Where provided, the farebox shall be located as far forward as practicable and shall not obstruct traffic in the vestibule, especially wheelchairs or mobility aids.

1192.35 Public information system.

(a) Vehicles in excess of 22 feet in length, used in multiple-stop, fixed-route service, shall be equipped with an automated stop announcement system.

(b) The same or equivalent information included in automated stop announcements shall be provided in a visual format.

1192.37 Stop request.

(a) Where passengers may board or alight at multiple stops at their option, vehicles in excess of 22 feet in length shall provide controls adjacent to the securement location for requesting stops and which alerts the driver that a mobility aid user wishes to disembark. Such a system shall provide auditory and visual indications that the request has been made.

(b) Controls required by paragraph (a) of this section shall be mounted on a side wall, panel or partition adjacent to the required clear floor space no higher than 48 inches and no lower than 15 inches above the floor. Control centerlines shall be within 3 inches of a line midway between the forward and rearward limits of the required clear floor space. Controls shall be operable with one hand and shall not require tight grasping, pinching, or twisting of the wrist. The force required to activate controls shall be no greater than 5 lb (22.2 N).

1192.39 Destination and route signs.

(a) Where destination or route information is displayed on the exterior of a vehicle, each vehicle shall have illuminated signs on the front and boarding side of the vehicle.

(b) Characters on signs required by paragraph (a) of this section shall comply with the following:

(1) Proportions. Characters shall be selected from fonts where the width of the uppercase letter "O" is 55 percent minimum and 110 percent maximum of the height of the uppercase letter "I".

(2) Height. Characters on signs on the boarding side shall have a minimum height of 2 inches. Characters on headsigns shall have a minimum height of 4 inches.

(3) Stroke thickness. Stroke thickness of the uppercase letter "I" shall be 10 percent minimum and 30 percent maximum of the height of the character.

(4) Character spacing. Character spacing shall be measured between the two closest points of adjacent characters, excluding word spaces. Spacing between individual characters shall be 10 percent minimum and 35 percent maximum of character height.

(5) Line spacing. Spacing between the baselines of separate lines of characters within a message shall be 135 percent minimum and 170 percent maximum of the character height.

(6) Contrast. Characters shall contrast with their background with either light characters on a dark background or dark characters on a light background.