Index Measures Impact of Heat on Pedestrian Activity

New research from MIT finds that, unsurprisingly, high heat and humidity encourage people to choose to drive for trips that they would otherwise make by foot or transit.

As Christian MilNeil explains in Streetsblog Mass, the researchers calculated the influence of the “Universal Thermal Climate Index” (UTCI) incorporates wind speeds and radiant temperatures (“which vary according the amount of shade and heat-absorbing materials, like hot asphalt”) into the traditional heat index measurement, which combines heat and humidity. 

This index is more accurate to how people make choices about their travel based on perceived discomfort. As one researcher explained, “What that means is, if I am walking along a street, and there’s a 1 degree increase in perceived temperature, that block is going to feel like a longer walk, 81 meters longer, because it's hotter.”

The results have implications for policymakers and planners who want to encourage people to walk and use transit. Shade, cooling pavement, and other infrastructure interventions can increase the distance that people are willing to walk and make cities safer and more comfortable.