Bus Pull Off – Turn Outs – Bus Bays – Cut Outs

Below is a summary of requirements and specifications for bus turnouts, primarily based upon information provided in the INDOT Design Manual. Used with the Shelter Site Design Specs, this information may be helpful to other engineering consultants in the design of turnouts in combination with bus shelter pads.

A bus turnout is a designated area on the side of a main road where buses can stop in order to pick up and drop off passengers. Bus turnouts (also known as pull-offs, pull-outs, bus bays, etc.) are meant to decrease the disruption of traffic along the main road and improve passenger safety during boarding and deboarding. According to Chapter 51 of the INDOT Design Manual, bus turnouts should be considered under the following conditions:

1. The street provides arterial service with high traffic speeds and volumes and high-volume bus patronage.
2. Right-of-way width is sufficient to prevent adverse impact on sidewalk pedestrian movements.
3. Where curb parking is permitted but is prohibited during peak hours.
4. During peak-hour traffic, where there are at least 500 vehicles per hour in the curb lane.
5. Bus volumes do no justify an exclusive bus lane, but there are at least 100 buses per day and at least 10 to 15 buses during the peak hour.
6. The average bus dwell time generally exceeds 10 seconds per stop.
7. At locations where specially equipped buses are used to load and unload handicapped individuals.

In designing the turnout, the following guidelines should be followed (per the INDOT Design Manual):

- If possible, the turnout should be 12’ wide. The turnout shall be a minimum of 10’ wide.
- The full-width area of the turnout should be at least 50’ long. If articulated buses (buses with an extra axle that provide increased capacity) are expected, the full-width area of the turnout should be at least 70’ long. If two buses are expected to utilize the turnout simultaneously, add 50’ to the length of the full-width area.
- The entering taper should be no sharper than 5:1; the exiting taper should be no sharper than 3:1. Short horizontal curves may also be used as an alternative, with radii of 100’ on the entry end and radii of 50’ to 100’ on the exit end. When a turnout is located at a far-side stop location, the cross street area can be considered to fulfill the need for the entry area. When a turnout is located at a nearside stop location, the cross street area can be considered to fulfill the need for the exit area.

Additionally, the pavement for the turnout should be a minimum of 8” portland cement concrete pavement with 8”x8” woven wire mesh reinforcement on a minimum of 4” compacted aggregate sub base. This pavement information is based on the design standards and recommended cross-sections of other municipalities in the region. Local guidelines and/or requirements may differ and shall supersede the above described pavement section.

Furthermore, all ADA requirements and specifications for shelter sites, as outlined in the Shelter Site Design Specs. Any changes/revisions to Chapter 51 of the INDOT Design Manual should be considered as well. Figure 1 summarizes guidelines for bus turnout design.

Figure 1 - Guidelines for Bus Turnout Design