Appendix H. Level of Traffic Stress and Bicycle Network Analysis This memo documents the methodologies used to complete the Bicycle Network Analysis. This consists of two steps: 1) calculation of the Level of Traffic Stress for all streets and trails countywide, and 2) calculation of low stress bicycle connectivity at the census block level using the Bicycle Network Analysis tool.
DATA AVAILABILITY AND ASSUMPTIONS Level of Traffic Stress (LTS) calculation is based upon several key factors further explained in the section below. Data for these factors was not available in all cases throughout Napa County, so it was necessary to make assumptions based on available data. This is a typical step for LTS calculations as jurisdictions throughout the country do not have full data available. Data necessary for LTS calculation include the following: •
Number of travel lanes
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Speed limit
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Traffic volume
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Bicycle facility type
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On-street parking presence
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Width of bike lane
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Width of parking
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Centerline presence
Full data was available countywide for the following factors: •
Number of travel lanes
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Bicycle facility type
For all other factors, assumptions were made based on street classification. Classification data was provided by NVTA and covered all streets in Napa County. The following assumptions were made: •
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Speed limit o Highway: 50 mph o Major Arterial: 40 mph o Minor Arterial: 35 mph o Collector: 30 mph o Local: 25 mph
Traffic volume (note that volume is only used for evaluating shared lane conditions either where no facility is present, or for Bike Route (class III) facilities) o Highway or Major Arterial: 30,000 ADT Page 1