Welcome to Rate My Treads

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Rate My Treads testing method

How We Test Footwear Slip Resistance

The Maximum Achievable Angle (MAA) Test

The MAA method measures the steepest angle a tester can walk on a controlled surface before the footwear begins to slip. Rate My Treads uses this approach in RampLab for water-contaminated surfaces and in WinterLab for ice.

Water-contaminated surfaces

RampLab: WaterDrop Testing

Our scientists at The KITE Research Institute use the Maximum Achievable Angle (MAA) Test to evaluate footwear slip resistance on water-contaminated tiles in RampLab. The method measures how steeply a person can walk on a wet surface before the footwear begins to slip.

How the WaterDrop test works

  1. Start on a level wet surface. Each tester begins walking back and forth on a tile surface contaminated with water.
  2. Increase the slope. We gradually increase the angle of the wet walking surface while the tester continues walking.
  3. Keep going until slipping occurs. The angle is increased until the footwear can no longer maintain grip. All four testers wear a full safety harness throughout the test.
  4. Determine the MAA. Each of the four testers receives an individual Maximum Achievable Angle score—the steepest angle they can achieve before slipping.
  5. Set the final MAA score. To provide a conservative measure of footwear performance, the lowest MAA score among the four testers is used as the final MAA score for that footwear.
  6. Assign the WaterDrop Rating. The final MAA score is used to determine the footwear's WaterDrop Rating, helping you identify footwear with better grip on wet surfaces.

The MAA test in action

  1. Tester walking on the RampLab surface at the beginning of the Maximum Achievable Angle test.
    Step 1: The tester begins walking back and forth on the test surface at a low angle.
  2. Tester walking on the RampLab surface as the ramp angle is gradually increased.
    Step 2: The ramp is gradually raised while the tester continues walking.
  3. Tester walking on a steeper RampLab surface while wearing a safety harness.
    Step 3: The angle continues to increase while the tester walks safely in a full-body harness.
  4. Tester walking on the RampLab surface at a steep angle during footwear slip-resistance testing.
    Step 4: Testing continues until the footwear begins to slip. The angle reached is used to determine the Maximum Achievable Angle.

The higher the angle, the better the measured slip resistance.

Our WaterDrop Rating System

WaterDrop Rating legend showing higher MAA scores as better wet-surface slip resistance.

The WaterDrop Rating is designed to make footwear slip-resistance performance on wet surfaces easy to understand. The rating is based on the final MAA score, with higher scores indicating that footwear can maintain grip at steeper angles before slipping.

  • Three WaterDrop: Final MAA score of 20° or higher
  • Two WaterDrop: Final MAA score of 15° to 19°
  • One WaterDrop: Final MAA score of 11° to 14°
  • No WaterDrop: Final MAA score of less than 11°

We selected 11° as the minimum WaterDrop threshold based on an established human-performance benchmark for footwear slip resistance and the historical HSE GRIP footwear assessment, which used ramp-based testing to classify slip-resistant footwear. The WaterDrop Rating is an independent Rate My Treads rating and is not an HSE certification or endorsement.

Tested on Water-Contaminated Surfaces

WaterDrop testing is conducted on dry and water-contaminated tile surfaces in RampLab to represent various walking conditions. The controlled environment lets us compare footwear under the same test conditions.

A Conservative Rating for Safety

Each footwear model is tested by four testers. The final MAA score uses the lowest MAA observed among the four testers, rather than an average or best-performing result.

Dry and Wet Surface Performance

We also indicate whether footwear demonstrated the required performance under both dry and wet conditions.

  • Wet Surface Passed the applicable MAA threshold under wet conditions.
  • Dry Surface Passed the applicable MAA threshold under dry conditions.
  • Wet Surface Did not pass the applicable MAA threshold under wet conditions.
  • Dry Surface Did not pass the applicable MAA threshold under dry conditions.
Ice surfaces

WinterLab: SnowFlake Testing

Our scientists at The KITE Research Institute use the Maximum Achievable Angle (MAA) Test to evaluate footwear slip resistance on ice in WinterLab. The method measures how steeply a person can walk on an icy surface before the footwear begins to slip.

How the SnowFlake test works

  1. Start on level ice. Each tester begins walking back and forth on a surface covered entirely with ice.
  2. Increase the slope. We gradually increase the angle of the icy walking surface while the tester continues walking.
  3. Keep going until slipping occurs. The angle is increased until the footwear can no longer maintain grip. All four testers wear a full safety harness throughout the test.
  4. Determine the MAA. Each of the four testers receives an individual Maximum Achievable Angle score—the steepest angle they can achieve before slipping.
  5. Set the final MAA score. To provide a conservative measure of footwear performance, the lowest MAA score among the four testers is used as the final MAA score for that footwear.
  6. Assign the SnowFlake Rating. The final MAA score is used to determine the footwear's SnowFlake Rating, helping you identify footwear with better grip on ice.

The MAA test in action

  1. Tester beginning the WinterLab MAA test on a level icy surface.
    Step 1: The tester starts on level ice.
  2. Tester walking across the icy WinterLab surface as the slope is increased.
    Step 2: The tester walks back and forth while the slope is increased gradually.
  3. Tester wearing a safety harness while the icy walking surface reaches a steeper angle.
    Step 3: The angle continues to increase until the footwear begins to slip.
  4. WinterLab MAA test at the maximum angle reached before the footwear slips.
    Step 4: The angle immediately before slipping is recorded as the Maximum Achievable Angle.

The higher the angle, the better the measured slip resistance.

Our SnowFlake Rating System

SnowFlake Rating legend showing higher MAA scores as better ice-surface slip resistance.

The SnowFlake Rating is designed to make footwear slip-resistance performance on ice easy to understand. The rating is based on the final MAA score, with higher scores indicating that the footwear can maintain grip at steeper angles before slipping.

  • Three SnowFlake: Final MAA score of 15° or higher
  • Two SnowFlake: Final MAA score of 11° to 14°
  • One SnowFlake: Final MAA score of 7° to 10°
  • No SnowFlake: Final MAA score of less than 7°

We selected 7° as the minimum threshold because it corresponds to the maximum allowed curb ramp slope under accessibility requirements. This provides a practical benchmark for footwear performance: we want footwear rated with at least one SnowFlake to provide good grip to help a person walk on an icy sidewalk in the winter.

Tested Under Different Winter Conditions

We test footwear on both cold ice and wet ice, from conditions similar to an icy parking lot to a wet, slippery sidewalk. We also test participants walking both uphill and downhill.

A Conservative Rating for Safety

Each footwear model is tested by four testers. The final MAA score uses the lowest MAA observed across all four testers, both ice conditions (cold and wet), and both walking directions (uphill and downhill).

Cold Ice and Wet Ice Performance

We indicate whether footwear demonstrated the required performance under both cold-ice and wet-ice conditions.

  • Wet Ice Passed the applicable MAA threshold under wet-ice conditions.
  • Cold Ice Passed the applicable MAA threshold under cold-ice conditions.
  • Wet Ice Did not pass the applicable MAA threshold under wet-ice conditions.
  • Cold Ice Did not pass the applicable MAA threshold under cold-ice conditions.

Publications and Research

If you're interested in learning more about how we developed our testing protocol and our publication work, email ratemytreads@uhn.ca (opens email application).