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Bike ISI Calculator

 

The following documents accompany this Pedestrian and Bicyclist Intersection Safety Indices (ISI) Calculator:

Pedestrian and Bicyclist Intersection Safety Indices: User Guide (Publication No. FHWA-HRT-06-130)
Pedestrian and Bicyclist Intersection Safety Indices: Final Report (Publication No. FHWA-HRT-06-125)

Download Excel Version

Approach 1 Approach 2 Approach 3 Approach 4
 
Name of approach leg
       
MAINADT
Main Street ADT        
MAINHISPD
Main street speed limit ≥ 35 mph (1=yes, 0=no)        
TURNVEH
Presence of turning vehicle traffic across the path of through cyclists (1=yes, 0=no)        
RTLANES
Number of right turn traffic lanes on main street approach        
BL
Bike lane present (1=yes, 0=no)        
CROSSADT
Cross street traffic volume        
SIGNAL
Traffic signal at intersection (1=yes, 0=no)        
PARKING
On-street parking on main street approach (1=yes, 0=no)        
RTCROSS
Number of traffic lanes for cyclists to cross to make a right turn        
CROSSLNS
Number of through lanes on cross street        
LTCROSS
Number of traffic lanes for cyclists to cross to make a left turn        

 

Safety Index Through Value =
       
Safety Index Right Turn Value =
       
Safety Index Left Turn Value =
       

The image shows an overhead view of an intersection with crosswalk  lines. The left-right street is labeled Main Street and the up-down street is labeled Cross Street. The Main Street approach leg on the right side is labeled as the approach of interest. The point is that 'main' street does not refer to the street with the higher traffic volume, but rather the street that on which the approach leg of interest lies.

 

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