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Our Maps & Ratings

See how we map Effort, Stress, and other features of Paths, Routes, and Trails

Traffic Stress

Bicycle levels of traffic stress (BLTS) overview... Alta provides an excellent summary of the traffic stress model for those interested in reading more. 

BLTS for each relevant road segment within an identified route are drawn from analyses conducted by Delaware Valley Regional Planning Commission (DVRPC - see right) and New Castle County.

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On our maps, higher levels of traffic stress are represented using larger circles for each 30' section.

 

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Descriptors are used in the text corresponding to the level of traffic stress as follows: Level 0 - No Stress; Level 1 - Very Low Stress; Level 2 - Low Stress; Level 3 - Moderate Stress; Level  - High Stress.

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A modified BLTS

One of the limitations of BLTS is that is was developed and has been used primarily in urban and suburban settings.  The BLTS model yet to be adapted to accommodate conditions more often found in rural settings. For sections of the route where we have additional information, we have modified the BLTS model as described below.

  • Actual prevailing speeds and/or volumes: DVRPC derives their ratings based on assumptions about speed (e.g., posted speed limits) and volume given the type of road, not on actual traffic studies. In rural regions like Kennett, drivers are more likely to speed, and volumes can sometimes be very low.  We indicate wherever actual traffic studies change BLTS. 

  • Limited Sight Distance: mmmThis used in some cases where additional information is available regarding the likely presence of sections with limited sight distance (see below) or (these models otherwise use posted speed limits and estimated volumes to model traffic stress).

Every 30' section on the route for which BLTS has been modified is outlined in red..

 like sections with limited sight distance (see below).

Limited sight sections

because of the road’s horizontal or vertical curvature, sometimes worsened by shrubs or trees. Drivers may not be able to see far enough ahead to safely pull around cyclists, increasing the risk of accidents.

We used William’s (2021) paper to establish minimum sight distances (i.e., 2 times the stopping sight distance) based on posted speed (or prevailing speed, when these data were available. Because our interest was in perceived stress as well as actual danger, we added 50’ to the minimum sight distance. Whenever a section was suspected, we measured the sight distance and increased the BLTS by 1 point at each 20’ section for which sight distance was an issue.  

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