Control Zone Rally

This iPhone app is designed for a particular type of automobile rally called a Control Zone Rally or for any rally with a single stage having a single average speed the must be maintained over the entire stage.

In a Control Zone Rally you are given some combination of time, speed, and distance required to traverse a course from a defined starting point to a finish line. Your starting time will also be assigned as some minute or half minute after the hour in which the race begins.

Set these conditions by touching the "Setup" button to access a screen where the starting time, course time, course speed, or course distance can be entered. When you've set these conditions, touch the "New Rally or Leg" button in the upper right hand corner of the screen to return to the main screen where a map and your progress will be recorded.

The Start Now! button allows starting a new rally or a leg of a rally with a single click. This allows you to preset time, speed, and distance for the upcoming leg, and to touch the button exactly when the new leg begins. In other words, with the Start Now! feature, the user doesn't wait until the clock ticks down to a defined starting minute or minute and a half.

GPS inputs trace the path along the rally route. Measurements of actual versus ideal time and distance will be shown in seconds ahead or behind schedule. From time to time you may also record time and distance covered an the error against the ideal course time and distance by touching the Add Split button. As an option you can select the frequency of splits automatically every quarter, half, or full minute.

Options include subtraction of distance when you travel off course. A toggle button switches between on course (blue line) and off course (red line) travel. Time splits can be set for automatic error checks. Also, map type can be set to standard, satellite, or hybrid.

You may fine-tune the app's distance and clock figures to the rally's official measures with the options in the Adjust popup. Unlock to make adjustments and lock to save the changes you make and to prevent inadvertent changes.

Distance measurement can be set to miles or kilometers and time measurement can be set to minutes and seconds or decimal minutes. Make your selections in the app preferences in the iPhone's System Preferences.

An adjustment factor between 0.800 and 1.200 can be used to synchronize distance measured by GPS to rally distance. This adjustment applies to all distance measurements shown after the adjustment has been selected.

If the app's Time of Day (T.O.D.) clock shown at the bottom of the map view does not match the rally's official clock, you may synchronize the two clocks by making small adjustments as required.

For better GPS reception and improved accuracy while racing, third-party wireless GPS receivers are recommended. This app has been tested with Bluetooth connectivity to a Dual XGPS150A Universal GPS Receiver.

A heads-up display for the Driver shows the time error, the time remaining for the course, the distance error, and the average speed for the course.

Disclaimer: Continued use of GPS running in the background can dramatically decrease battery life.


changes in version 7.1
  • Created a new popup for Settings along with new options. Easier to change Settings within the app now
  • Increased the maximum time for a single Control Zone from 120 to 180 minutes to accommodate participants in long multi-stage, multi-day touring rallies
  • Also, increased the maximum distance to 180 miles from 120 miles (and 300 kilometers from 200 kilometers)
  • GUI enhancements
  • Minor bug fixes and code improvements
changes in version 7.0.1
  • Added code to ensure that background location tracking will take place for at least 3 minutes permitted by Apple
  • GUI modifications for improved readability
changes in version 7.0
  • Changed minimum required iOS version to 10.3 to resolve some issues and to accommodate new technology
  • Reduced from 10 meters to 1.5 meters (33 feet to 5 feet) the minimum distance computed from a pair of GPS coordinates suitable for incrementing distance. This improves displayed distance measurement to 0.001 mile accuracy, which is especially important at speeds less than 15 mph
  • Various changes to accommodate iOS 11
changes in version 6.4
  • GPS Info button shows information for either the Apple GPS or Dual GPS devices, whichever is currently operating
  • Fixed behavior of "Pause or Stop" option and show the time paused below the "Resume Rally" button
  • Heading has been changed to Bearing and is now computed from GPS coordinates rather than from Apple's built-in magnetometer
  • Minor GUI modifications
change in version 6.3
  • To eliminate "mileage creep" while stopped, the threshold for computing estimated distance between GPS ticks has been set a speeds greater than 15 miles per hour

revised: May 11, 2019