Chapter 2. Safety Performance Measures
2.5 Implementation of the Field Survey Instrument and Data Collection
The Pedestrian Safety Assessment Index (PSAI) and Bicyclist Safety Assessment Index (BSAI) data are collected through visual assessment of street segments and intersections with an observational survey (Appendix B, Tables 2B.1-2B.4) by a trained observer. The field observation materials were piloted as detailed in Chapter 6. Furthermore, Chapter 6 offers suggestions as to how university students can be engaged in data collection efforts. The research team has created some examples and guidebooks to aid training (see Chapter 7).
The survey is a checklist of questions with close-ended options that is relatively simple to complete. The survey captures broad criteria that potentially affect the safety risk to either pedestrians or bicyclists and the overall walkability and bikeability. Each survey element collects information on one or more responses (elemental options). Each observer completes a separate survey form for each individual intersection and street segment. The data entry in the form is saved in Microsoft Excel database for further analysis. After the data is entered into a database, responses are converted into binary responses and then index values are calculated. For a given road segment, summing the weighted scores of the applicable elemental options (known from the collected survey) yields an index value. A separate index is calculated for roadway segments (each direction) and intersections. Corridor level indexes are simply a length based weighted index of all segments and intersections. For intersections, consider a length of 250 feet in each direction while calculating the weighted index. Similarly, network based index measures are developed for the study area. Once index values are known, the safety level of the facility can be determined. An example of how to implement this is presented in Chapter 7.
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Appendix 2A: Survey Responses and Elemental Options Score
Table 2A.1 Pedestrian – Intersection Elements: Survey Responses, Element Weights and Options Score
Negatively Impact Safety Minimally Impact Safety Positively Impact Safety Total Responses
Presence of
Table 2A.2 Bicyclist – Segment Elements: Survey Responses, Element Weights and Options
Negatively Impact Safety Minimally Impact Safety Positively Impact Safety Total Responses
Number of
Table 2A.3 Bicyclist – Intersection Elements: Survey Responses, Element Weights and Options
Negatively Impact Safety Minimally Impact Safety Positively Impact Safety Total Responses
Presence of
Appendix 2B: Field Data Collection Forms
Table 2B.1 Pedestrian Safety Assessment Index at Segment Data Collection Form (Form Ped Safety Segment)
Pedestrian Safety - Segment - Data Collection Form
Location ID: Segment ID:
Presence of 4 to 6 foot buffer from curb line to sidewalk's near edge / presence of either on-street parking / presence of bike lanes
Table 2B.2 Byclist Safety Assessment Index at Segment Data Collection Form (Form Bike Safety Segment)
Bicyclist Safety - Segment - Data Collection Form
Location ID: Segment ID:
Excellent Visibility of Approaching Figures without Dark Spaces along the Road Segment
Moderate Visibility of Approaching Figures with Some Dark Spaces along the Road
Poor Visibility of Approaching Figures with Dark Spaces Present along the Road
Table 2B.3 Pedestrian Safety Assessment Index at Intersection Data Collection Form (Form Ped Safety Intersection)
Pedestrian Safety – Intersection
Location ID: Intersection ID:
Element Options Response
Presence of Crosswalks
Continental/Ladder/Staggered Continental Type on All
Directions
Standard/Parallel Type on All Directions
None
Pedestrian Time Counters
All Directions with Counters
Two Directions (on Major/Minor Road) with Counters
No Counters
No Pedestrian Phase
No Right-Turn-On-Red (RTOR)
No RTOR on All Directions
No RTOR on Two Directions (on Major/Minor Road)
Not Present
Table 2B.4 Bicyclist Safety Assessment Index at Intersection Data Collection Form (Form Bike Safety Intersection)
Bicyclist Safety - Intersection
Location ID: Intersection ID:
Element Options Response
Presence of Bicycle Lane or Bicycle Boxes at Left Turn Lanes (For Turning Bicyclist Movements)
Present on All Directions
Present on Two Directions (On Major/Minor
Road)
Shared Lanes on All Directions Presence of Bicycle Lanes or Bicycle
Boxes (For Non-Turning Bicyclist Movements)
Present on All Directions
Present on Two Directions (On Major/Minor
Road)
Shared Lanes on All Directions
None
No Right-Turn-On-Red (RTOR)
No Right-Turn-On-Red on All Directions No Right-Turn-On-Red on All Directions on Two Directions (On Major/Minor Road) Right-Turn-On-Red Allowed on All Poor Visibility of Approaching Figures with Dark Spaces Present along the Road
Pavement Markings for Bicyclists Adequate
None