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USA: SCCA TSD and the Great Race

American time-speed-distance (TSD) rallies restart the clock at every control, at a time the organiser assigns. This is the format the app fits least well.

Partial fit

The app has no pause, gain or time-allowance button, no 0.01 minute display and no timed speed changes. Some of these can be worked around, others cannot. Read "How well the app fits" before you plan to use it.

Not yet checked by a competitor

This page comes from the written rules. It has not been read by a US competitor yet. It is open whether clubs really use GPS controls timed "from the previous restart" in practice.

How this format times you

  • CAST. A change of average speed takes effect at a specific sign, landmark or official mileage. For a sign, it is the near edge [SCCA 23.E.4]. The Great Race also has speed changes that are timed, for example after "0m15s".
  • Pause. Time added to the leg. It is given at a point, or spread over a distance (a free zone).
  • Gain. Time subtracted over a distance, also a free zone.
  • Transit. No speed to hold. A fixed time or a restart time is given.
  • Time allowance. Always allowed, with no penalty, typically 1/2, 1 1/2 ... 19 1/2 minutes. It is declared at the next open control.
  • Legs do not add up. SCCA 16.B says penalties "shall under no circumstances be cumulative". At an open control you get an assigned out time, at least 2 minutes after your in time. A passage control may not use "in-time equals out-time". For GPS controls, the general instructions (GIs) say whether each is timed from the previous restart or from the previous control.
  • Great Race. In time equals out time, so it re-bases at the actual crossing. Lateness is judged against the "computed cumulative perfect time from the most recent Stage Start or Restart".
  • Precision. Leg times are computed to 0.0001 minute, summed without rounding, then truncated to the second or 0.01 minute. Penalties are 1 point per 0.01 minute (cap 200) in ABC and Detroit, 1 point per second (cap 300) in San Diego. The Great Race counts to the nearest second, with a late cap of 2 minutes and an early cap of 5 minutes.
  • Odometer. The organiser measures an official odometer check of at least 12 miles each day. "/0.00" re-zeroes the official mileage at a new section.

Stage setup

See Turning the roadbook into a stage.

  1. In Settings > Units, set Distance to mi and Speed to mph.
  2. Stage type Regularity. Start signal Time, at the out time of your start, or Tap.
  3. One section for each CAST from the instructions, with the Distance from the official mileage and the Speed from the CAST.
  4. A pause or gain spread over a distance: enter the Distance and the Time for that section, with the pause included in the time. The app works out the speed. For example 1 mile with a 50 s pause on a 100 s leg: Time 150 s. A pause at a single point has no equivalent.
  5. Keep Auto-switch sections by distance on, and use Sync at the sign. Or switch it off and use Next Section, because a CAST takes effect at the sign and not at a GPS distance. Next Section also sets the stage trip to the official mileage of the sign.
  6. Save one stage for each leg between restarts if you want to keep the chart short.

Button recipe

  1. Start. Load the stage and press Start.
  2. At a CAST sign. Press Sync (automatic sections) or Next Section (manual sections) when the front of the car is at the near edge of the sign. These do not restart the Ideal Time. Its number can move, because the distance changes.
  3. At a control. Long-press the Ideal Time, or press TC (custom layouts). The Checkpoints sheet opens with the TC just recorded, at your current trip. The TC time is the exact moment of your press.
  4. Set the restart to your out time. In the sheet, open Restart time on the new TC and pick:
    • +120s for "out time two minutes after in time";
    • Next minute for "top of the next minute";
    • Set and a clock time for an assigned out time, for example "in time plus car number in minutes".
  5. Close the sheet. The Ideal Time now runs from the out time.
  6. Passage control or Great Race checkpoint you can see. In time equals out time: record the TC and leave Restart time at 0s. For a hidden control, see Pitfalls.
  7. End. Press Finish.

Pitfalls

  • The restart is the assigned out time, not the moment you press. The out time is "in time plus 2 minutes" or "the car-number minute". Always set Restart time. The default is 0.
  • Hidden controls. Great Race and many SCCA controls are hidden. The app cannot re-base at a control you do not know about, so until you record a TC your display still counts from the last one. If you see the control as you pass it, press the TC then. If you press late, open the TC in the Checkpoints sheet and set TC time to the moment you passed.
  • Mileage drift. The official mileage is to 0.01 mile. Calibrate on the official odometer check, and use Sync at signs.
  • Time allowances. The app has no button for them. An allowance is taken off your time for the leg that ends at the control where you declare it. The app cannot do that: it shows that leg without the allowance, so read the Ideal Time as late by the allowance until the control. Restart time is a different thing: it only sets the assigned out time, the start of the next leg. Do not add the allowance to it.
  • Transit. Use Restart time > Set with the given restart time.

How well the app fits

This is the worst fit of the formats here. What works:

  • re-base at each control with a chosen restart time (Restart time, including a typed clock time);
  • miles and mph;
  • a pause or gain over a distance, by entering distance and total time.

What does not:

  • 0.01 minute display. The app shows seconds (and tenths under a minute). It cannot show centiminutes.
  • Time offsets. There is no pause, gain or time-allowance button. A pause at a point inside a leg has no clean equivalent: a TC there with a Restart time adds the pause, but it also restarts the ideal time from your press, so any lateness before that point drops out of the display. A time allowance cannot be applied to its leg at all.
  • Timed speed changes (Great Race "0m15s") are not distance-based.
  • GPS controls timed "from the previous restart". Whether a TC is right depends on the club's GIs, and the published rules do not settle it.
  • Emergency speeds. A second chart is a second saved stage.

Legality note

The SCCA rule book and club GIs set what a crew may use. The Great Race rules cover odometers and calibration. The sources do not say whether phone apps or ahead/behind displays are allowed in each club's GIs. Read them. This app is a crew aid, not official timing.

Sources

Article numbers in brackets.

  • SCCA 2025 RoadRally Rule Book [16, 17, 18.D, 21, 23.E]: PDF
  • Great Race 2026 regulations [V.A.1.a(2), VII.E.2]: PDF
  • ABC Region general instructions: PDF
  • San Diego Region general instructions: PDF
  • Detroit Region general instructions: PDF
  • Richta Competitor App guide: PDF