Race within the rules
This page explains what governing bodies, regulators, standards bodies and researchers publish. It is not a substitute for your class's rule book, a track's safety rules, the race director or the makers' instructions.
How automatic lap counting works
A transponder is a small device fitted to the car. The rule books describe lap counting as automatic: the timing system's decoder picks up each car's transponder and records its laps. IFMAR's electric off-road rules (2019, 1.15 and 2.18) name the MyLaps system "or IFMAR approved equivalent", run in duplicate with two loops. IFMAR's 1/8 IC off-road rules (2024, 3.9) say transponders are fitted to each car's body shell or chassis.
In IFMAR's 1/8 IC off-road qualifying, timing for each car starts the first time it crosses the start line, which the rules call a "flying" start (2024, 3.2).
Two systems at once
IFMAR and EFRA both require two timing systems running side by side, each body in its own words:
- IFMAR 1/8 IC off-road (2024, 3.9.a to 3.9.e): two independent approved systems (AMB/MyLaps or an IFMAR-approved equivalent) run at the same time and record lap times to 1/100 second. If the two systems differ, the Time-Keeper decides the result.
- EFRA (Handbook 2024, General Rules, 5.4.1 to 5.4.7): two completely independent lap-counting systems must run at the same time at EFRA-sanctioned events, operated by the organising club and recording to 1/100 second.
IFMAR's 1/8 IC off-road rules add that no lap score from any source other than the official timing equipment is accepted (3.9.k). For tracks seeking IFMAR affiliation, IFMAR's 2021 criteria call for IFMAR-approved timing with live timing.
Personal transponders: whose risk
A personal transponder is the driver's own, as distinct from timing equipment that an organiser hands out, which EFRA's rules also allow. The bodies differ in when one is required; IFMAR's and EFRA's rules both put the risk on the driver.
| Body and rule | What it says |
|---|---|
| IFMAR 1/8 IC off-road (2024, 3.9.i to 3.9.k) | Every competitor uses their own AMB/MyLaps-compatible personal transponder; fitting it securely is the driver's responsibility. |
| IFMAR electric off-road (2019, 1.15 and 2.18) | Competitors install a small compatible transponder. An IFMAR-approved personal transponder may be used if the lap counting officials agree, but laps missed with a transponder not specified by the decoder maker are the driver's responsibility. |
| EFRA electric (Handbook 2026, App. 3, A.5.1 to 5.2, A.12.6) | Cars must allow a transponder to be fitted in a suitable position and orientation. Organisers may hand out timing equipment, which the driver fits and removes. A driver using a personal transponder is entirely responsible for its working. |
| EFRA GT12 (App. 3, C.1.24) | Only personal transponders are used to record laps. |
| ROAR Nationals (guidelines rev. 13 October 2026, 4.5.10) | The race flyer must include a statement on the mandatory use of personal transponders. |
A search summary of the BRCA's 12th circuit national series page says the BRCA advises against pure RC4 transponders (it names AMB "Percy" and Pro models) at its events. That page was not opened, so the advice is unconfirmed.
When a transponder fails
The rule books are strict about missing laps:
- IFMAR's electric off-road rules (2019) say a car that starts without a transponder, or with the wrong one, is not counted, and no heat is re-run for a transponder failure.
- IFMAR's 1/8 IC track (2023, 4.6) and 1/10 IC track (2024, 4.6) rules say each participant attaches the transponder; in qualifying a car without one is not counted, and in finals a manual back-up count is used. No heat or final is re-run for a missing or failed transponder.
The transponder and the rest of the car
Two other kinds of rule touch the transponder. First, it is included in the car's weight in several classes: IFMAR's 1/10 IC track minimum of 1650.00 g includes the transponder (2024, 5.9), as do EFRA's minimum weights for Formula One and front-wheel drive, and EFRA states that all its electric weight minima apply to cars fitted with a personal transponder (App. 3, A.12.19). Second, EFRA allows no signal to be sent from an electric car except the official lap-counting transponder's (App. 3, A.4.4), and permits a separate battery supply for timing equipment (A.4.1).
What the timing system announces
EFRA's electric rules (Handbook 2026, App. 3, A.1.4.1) require the timing computer to make automatic announcements in clear English: two minutes and 30 seconds to the start, a 10-second countdown, time and race order every two minutes, and race over. How the times feed qualifying points and finals is on how a race meeting works.
Sources
- IFMAR 1/8th I.C. Off-Road Racing and Technical Rules, World Championship 2024 (amended March 2024)
- IFMAR Electric Off Road Racing and Technical Rules, version 13 November 2019
- IFMAR 1/8th I.C. Track Racing and Technical Rules, World Championship 2023 (amended March 2023)
- IFMAR 1/10th I.C. Track Racing and Technical Rules, World Championship 2024
- IFMAR, Associated membership (7 March 2021)
- EFRA Handbook 2024, General Rules
- EFRA Handbook 2026, Appendix 3 (electric cars), v4 (June 2026)
- ROAR, Appendix C: National Guidelines for National Race Management Team Events (revised 13 October 2026)
- BRCA, 12th Circuit LMP12 national series (search-result summary only)