Level of Traffic Stress (LTS) is a rating given to a road segment or crossing indicating the traffic stress it imposes on bicyclists. Levels of traffic stress range from 1 to 4 as follows:[1]

• LTS 1: Strong separation from all except low speed, low volume traffic. Simple crossings. Suitable for children.
• LTS 2: Except in low speed / low volume traffic situations, cyclists have their own place to ride that that keeps them from having to interact with traffic except at formal crossings. Physical separation from higher speed and multilane traffic. Crossings that are adult to negotiate. Corresponds to design criteria for Dutch bicycle route facilities. A level of traffic stress that most adults can tolerate, particularly those sometimes classified as "interested but concerned".[2]
• LTS 3: Involves interaction with moderate speed or multilane traffic, or close proximity to higher speed traffic. A level of traffic stress acceptable to those classified as "enthused and confident."[2]
• LTS 4: Involves interaction with higher speed traffic or close proximity to high speed traffic. A level of stress acceptable only to those classified as "strong and fearless."[2]

Source code used to generate the LTS data on this map: GitHub: bikespace/LTS-OSM.[3]

The code is a fork of Madeliene Bonsma-Fisher's implementation of calculating LTS from OSM data[4], which is itself adapted from Bike Ottawa's LTS code.[5]