The Boston Pedestrian Wind Criteria is the standard used by the Boston Planning and Development Agency (BPDA) to assess wind impacts on pedestrian safety and comfort. Strong winds and wind gusts can negatively impact the pedestrian experience and may even pose a safety risk.
The BPDA Criteria identifies standards for Wind Acceptability and Wind Comfort. Winds are “acceptable” if the Effective Gust Speed (Mean wind speed + 1.5 times the root-mean-square wind speed) does not exceed 31 mph (50 kph). Winds are “comfortable” for a particular activity if the average hourly wind speeds do not exceed the threshold specified for that activity.
Comfort categories and Wind Acceptability limits are defined such that the average wind speeds and effective gust speeds, respectively, must remain below the category threshold at least 99% of the time (see table below).
| Activity | Description | Mean Wind Speed (mph) | Mean Wind Speed (kph) | Mean Wind Speed (m/s) |
|---|---|---|---|---|
| Sitting | Calm or light breezes. Ideal for outdoor dining and seating areas where one can read a paper without having it blown away. | ≤ 12 | ≤ 19 | ≤ 5.3 |
| Standing | Gentle breezes. Acceptable for building entrances, bus stops, and other places where pedestrians may linger. | ≤ 15 | ≤ 24 | ≤ 6.7 |
| Walking | Moderate winds. Acceptable for window shopping or leisurely strolls across a park or plaza. | ≤ 19 | ≤ 31 | ≤ 8.6 |
| Uncomfortable for All Activities | Strong winds which discourage pedestrian activity. Mitigation is typically recommended. | > 19 | > 31 | > 8.6 |
| Safety Criterion | Description | Effective Gust Speed (mph) | Effctive Gust Speed (kph) | Effective Gust Speed (m/s) |
| Dangerous for All Activities | Extremely strong winds/ gusting which pose a safety risk to pedestrians. Mitigation is typically required. | > 31 | > 50 | > 13.9 |
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