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Walkthrough & Information
For This Year's International Roadeo
Official event description, system component reference, defect identification rules, and scoring guide for the APTA International Bus Roadeo Air Brake System competition event.
2026 International Bus Roadeo — Salt Lake City, UT · May 15–19
Salt Lake City, Utah
May 15–19, 2026 · APTA Mobility Conference
Combined with the APTA Mobility Conference & Expo
View on Google Maps
Air System Training Walkthrough
and Information
International Roadeo
Presented by
Custom Training Aids & Fraser Gauge
APTA Roadeo Air System — Overview Video
Custom Training Aids / Bendix ABS Event
Section 2.5 — APTA International Bus Roadeo Official Rules
System Description
The competition uses a fully functional air brake system with ABS components, representing a current model year 40-foot, 2-axle transit bus equipped with an antilock brake system. The board is manufactured to meet current Federal Motor Vehicle Safety Standard 121.
- Air reservoirs and brake chambers are reduced in size to limit air consumption while maintaining precise control
- Foundation brake system represents an 'S' Cam spring-braked vehicle
- ABS: WABCO 'D' version 4S/4M 12V system with cab-mounted ECM and transmission retarder control relay
- Brake valves manufactured by Bendix — common to most current FMVSS 121 transit buses
- Air compressor is a cut-away demonstration unit; unloader valves are fully functional
Air Line Color Code
All air lines are color-coded per the APTA standard for rapid identification during troubleshooting.
System Components
Complete component list per APTA Brake Task Force specification (Section 2.5.2)
Defect Identification Rules
Air Brake System Electrical/Pneumatics Diagnostics
- Teams must use a Digital Multimeter (DMM) to diagnose an electrical component
- Electrical component may include: electric relays, sensors, wiring harness, etc.
- Part I is timed and serves as the tiebreaker — fastest correct diagnosis wins in the event of a tie
Air Brake System Trouble Shooting
- Teams must inspect, locate, identify, and legibly record (including location) all 6 planted defects
- Defects are mechanical in nature — not air line or connection leaks
- Identification does not require the system to be repaired, taken apart, or disconnected
7 Minutes
Total time allotted for the event
Scoring
Section 2.5.5 — Official APTA Roadeo Scoring Rules
350
Total Possible Points
50 pts
Part I — Electrical/Pneumatics Diagnosis
50 pts each
Part II — Each of 6 Planted Defects Found
−10 pts
Penalty: Misuse of diagnostic/test equipment
−10 pts
Penalty: Safety violation incident
−10 pts
Penalty: ABS board not returned to original status
Official APTA Roadeo Rules — Air Brake System Event
Section 2.5 · APTA Brake Task Force Committee · PDF
Additional Scoring Rules
- Points are given only for recorded defects that were planted by the judges. No credit for defects not planted.
- Only 6 defects are to be listed. If more than 6 are listed, only the first 6 count. Unwanted listings may be crossed out prior to time expiration.
- The team must notify the judges when finished. Once notice is given, no additional defects may be listed.
- Judges will review the defect list with each team for clarification.
- Tiebreaker: Fastest time to correctly diagnose and record Part I (Electrical/Pneumatics Diagnostics) determines the winner.
Practice Defect Checklist
Print this sheet and use it during practice sessions. Record defects found on each of the 23 system components.
| # | System Component | Defect Found / Location | Correct? |
|---|---|---|---|
| 01 | Tu-Flo 700 Air Compressor | Yes / No | |
| 02 | D-2 Air Governor (cutout: 120 PSI) | Yes / No | |
| 03 | AD-9 Air Dryer with 175 PSI ST-3 safety valve | Yes / No | |
| 04 | Puraguard oil separator (post air dryer) | Yes / No | |
| 05 | E-6 Brake application valve | Yes / No | |
| 06 | R-12DC Service brake relay valve (crack pressure: 5.5 PSI) | Yes / No | |
| 07 | R-14 Spring brake relay valve (crack pressure: 4.0 PSI) | Yes / No | |
| 08 | QR-1 Front service brake valve (crack pressure: 0 PSI) | Yes / No | |
| 09 | SR-1 Spring brake modulation valve | Yes / No | |
| 10 | SL-5 Stop light switches (activate at 5 PSI) | Yes / No | |
| 11 | LP-3 Low-pressure switches (rated at 70 PSI) | Yes / No | |
| 12 | RV-1 Interlock pressure regulator (adjusted to 45 PSI) | Yes / No | |
| 13 | PR-3 Pressure protection valve (opens at 92–98 PSI) | Yes / No | |
| 14 | PP-1 Control valve (application pressure: 40 PSI) | Yes / No | |
| 15 | RD-3 Spring brake emergency release valve | Yes / No | |
| 16 | Duplex instrument panel air pressure gauge (green = Primary, red = Secondary) | Yes / No | |
| 17 | ST-3 Safety valve (150 PSI) | Yes / No | |
| 18 | SC-3 Single check valves | Yes / No | |
| 19 | DC-4 Double check valves | Yes / No | |
| 20 | WABCO open-style modulator valves | Yes / No | |
| 21 | SAB automatic slack adjusters | Yes / No | |
| 22 | Type-20 front service brake chambers | Yes / No | |
| 23 | Type-24 Service/Spring brake chambers | Yes / No | |
Team Name: Date: Total Defects Found (max 6):/ 6 | |||
Official rules: Section 2.5 · APTA Brake Task Force Committee · Presented by Fraser Gauge · Detroit
Need Roadeo-Ready Components?
Fraser Gauge stocks Bendix, WABCO, and Meritor air brake components used in the APTA Roadeo demonstration board. Same-day shipping from Detroit.