Default
Maximum Overall Height
Maximum overall height shall be 140 in., including all rigid, roof-mounted items such as A/C, exhaust, fuel system and cover, etc.
Alternative
Maximum Height
Maximum height shall be specified by Agency.
Step Height Transit Coach
The step height shall not exceed 16.5 in. at either doorway without kneeling and shall not exceed 15.5 in. at the step. A maximum of two steps are allowed to accommodate a raised aisle floor in the rear of the bus.
Commuter Coach
The step height shall not exceed 16.5 in. at doorway without kneeling and shall not exceed 15.5 in. at the step.
Articulated Coach
The center door on an articulated bus may have more than two steps.
Underbody Clearance
The bus shall maintain the minimum clearance dimensions as defined and shown in Figure 2of SAE Standard J689, regardless of load up to the gross vehicle weight rating.
The approach angle is the angle measured between a line tangent to the front tire static loaded radius arc and the initial point of structural interference forward of the front tire to the ground.
The departure angle is the angle measured between a line tangent to the rear tire static loaded radius arc and the initial point of structural interference rearward of the rear tire to the ground.
The breakover angle is the angle measured between two lines tangent to the front and rear tire static loaded radius and intersecting at a point on the underside of the vehicle that defines the largest ramp over which the vehicle can roll.
Default
Refer to Table 2a.
TABLE 2a
Default Breakover Angle
|
Angle
|
30 to 45ft Bus
|
60ft Bus
|
Approach
|
8.6 deg (min.)
|
8.6 deg (min.)
|
Front breakover
|
8 deg (min.)
|
10.2 deg (min.)
|
Rear breakover (articulated only)
|
n/a
|
8.7 deg (min.)
|
Departure
|
8.6 deg (min.)
|
8.6 deg (min.)
|
Alternative
Refer to Table 2b.
TABLE 2b
Alternative Breakover Angle
|
Angle
|
30 to 45 ft Bus
|
60 ft Bus
|
Approach
|
8.6 deg (min.)
|
8.6deg (min.)
|
Front breakover
|
7.5deg (min.)
|
10.2 deg (min.)
|
Rear breakover (articulated only)
|
n/a
|
8.7 deg (min.)
|
Departure
|
7.5deg (min.)
|
8.6deg (min.)
| Ground Clearance
Ground clearance shall be no less than 9 in., (8 in. at jacking pad) except within the axle zone and wheel area.
Axle zone clearance, which is the projected area between tires and wheels on the same axial centerline, shall be no less than 5.4 in.
Wheel area clearance shall be no less than 8 in. for parts fixed to the bus body and 6 in. for parts that move vertically with the axles.
Transit Bus Minimum Road Clearance
|
|
|
Transit Coach
Height of the step above the street shall be no more than 16 in. measured at the centerline of the front and rear doorway. All floor measurements shall be with the bus at the design running height and on a level surface and with the standard installed tires. A maximum of two steps are allowed to accommodate a raised aisle floor in the rear of the bus.
Commuter Coach
Height of the step above the street shall be no more than 16 in. measured at the centerline of the doorway. All floor measurements shall be with the bus at the design running height and on a level surface and with the standard installed tires.
Interior Headroom
Headroom above the aisle and at the centerline of the aisle seats shall be no less than 78 in. in the forward half of the bus tapering to no less than 74 in. forward of the rear settee. At the centerline of the window seats, headroom shall be no lower than 65 in., except for parcel racks and reading lights, if specified. Headroom at the back of the rear bench seat may be reduced to a minimum of 56 in., but it shall increase to the ceiling height at the front of the seat cushion. In any area of the bus directly over the head of a seated passenger and positioned where a passenger entering or leaving the seat is prone to strike his or her head, padding shall be provided on the overhead paneling.
VEHICLE PERFORMANCE
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