Place for Existing Data and Basic Information to Keep Everyone Safe (PEDBIKES)

Bicyclists In Traffic

This document intends to provide a guideline to cyclists on safe maneuver of conflict scenarios with other road users. At the first level, the scenarios are classified into urban and rural as traffic conditions under which conflicts may happen can be very different in rural areas than urban. At the second level, the scenarios are classified based on roadway relations – whether they are at intersections or at other locations (including driveways, midblocks, sidewalks etc.). The final classification is based on direction of travel – whether the bicyclist is travelling along the travel or attempting to cross the traffic or is turning when they experience the conflict scenarios. For each scenario, a brief description is presented and then a list of relevant references that provide guidance on best practices to avoid and safely maneuver such conflict situations.

Table of Contents

Urban

Urban bicyclist crashes are mostly characterized by low situational awareness and often, due to vision obstruction in multi-lane traffic. These are generally low speed crashes, predominantly happening at intersections.

Urban : At Intersection

This category includes both signal controlled intersections as well as stop sign controlled intersection, 2 way, 4 way and 6 way.

Urban : At Intersection : Parallel to traffic

The conflict scenarios under this category involve bicyclists that are riding along the direction of the vehicular traffic movement.

Motorist Turns Right with Bicyclist to Their Right (statistics in this study, [1])
  1. 51 participants completed a total of 1071 right-turns, 23 participants could not avoid a crash with a bicyclist in 26 total scenarios
  2. Relative position of a bicyclist, cyclist speed, and the presence of an oncoming vehicle were found to have a statistically significant effect on crash occurrence
    • Bicyclist in front of motorist: in 87% of the cases the motorists fixated on the bicyclist (i.e., actively scanned for the bicyclist before turning right)
    • Bicyclist was approaching from behind in the motorist’s blind zone, in only 44% of the scenarios did a motorist fixate on the bicyclist before turning right
    • Twenty-four crashes occurred with the bicyclist approaching from behind in the motorists’ blind spot and 21 of those crashes occurred in the presence of oncoming left-turning traffic
  3. The motorist did not check for the bicyclist in the mirror before turning in most cases (66% of cases)
  4. Motorist suffered from inattentional blindness (looking but not perceiving bicyclist) in some cases (15% of cases)
  5. Some right turn crashes (19% of cases) were caused due to the motorists’ poor projection, where he/she detected the conflicting bicyclist but did not yield the right-of-way.
  6. Drivers turning right simply focus their attention on the cars coming from the left—those coming from the right pose no threat to them—and fail to see the cyclist from the right early enough
  7. The presence of oncoming vehicles posed more of a threat to the motorist as compared to other objects in his field of view, and as such the motorist spent more time fixating on the oncoming vehicles than on the bicyclist.

Urban : At Intersection : In cross traffic

The conflict scenarios for this category include bicyclists who are attempting to ride across oncoming traffic.

Bicyclist Crashes into Motorist After Riding Out From a Stop Sign (statistics in this study, [2])
  1. Out of 290 cases, 9.7% of those crashes were of of this type of crash and 23% resulted in serious/fatal injury
  2. This type of crash is more likely to involve bicyclists age 0-14 years old
  3. 86% of crashes took place on 2 lane roads
  4. 88% of crashes happened on roads with speeds less than 60 km/h
Bicyclist Did Not Clear the Intersection Before the Light Turned Green for Cross Traffic and the Motorist’s View of the Bicyclist was Obstructed by Standing Traffic (Multi-Lane) (statistics in this study, [2])
  1. Out of 27 cases, (which was 0.9% of all crashes), 15% of cases resulted in serious or fatal injuries
  2. 55% of crashes occurred on high speed (60-70 km/h) or very high speed (80+ km/h) roads
Driver Turning Right and Cyclist Coming from the Right (statistics in this study, [3])
  1. This type of accident occurred in 27 out of 39 accident situations
  2. Drivers turning right continued to look left, the respective proportions of right-looking drivers only being 3% at the same locations.
The Bicyclist Made a Left in Front of Approaching Traffic (statistics in this study, [2])
  1. There were a total of 25 cases- 0.8% of all crashes
  2. 26% of crashes resulted in serious or fatal injuries; it causes a more severe accident than the average
  3. This type of accident is more likely to involve bicyclists aged 0-9 years old
  4. Almost 50% occurred on high-speed (60-70 km/h) and very high speed (80+ km/h) roads combined

Urban : At Intersection : Turning

This category is for the cases where the bicyclist is making a turn across or with the traffic.

The Bicyclist Made a Left in Front of Parallel Traffic (statistics in this study, [2])
  1. There were a total of 130 test cases- 4.3% of all crashes
  2. 28% of crashes resulted in serious or fatal injuries; it causes a more severe accident than the average
  3. This type of accident is more likely to involve 10-14 yr old bicyclists
  4. Likely to occur on high-speed, 2 lane roads

Urban : Non-Intersection Related

This category includes crashes that happen at midblocks, sidewalks, along on street parking, driveway and any such roadway area that is not an intersection.

Urban : Non-Intersection Related : Parallel to traffic

The conflict scenarios under this category involve bicyclists that are riding along the direction of the vehicular traffic movement.

The Bicyclist Rides Too Close to Parked Cars (statistics in this study, [4])
  1. If a crash occurred on the cycle lane and a one-way street, it was most likely this type of crash
  2. In order to prevent this type of crash, bicyclists should be instructed to ride at least one door’s width from parked automobiles, irrespective of whether or not they’re riding on cycle lanes
The Bicyclist Swerves to Avoid an Obstacle (statistics in this study, [5])
  1. An angle collision is the leading crash pattern associated with irregular maneuvers, such as bicycle swerving
The Bicyclist Rides Against the Flow of Traffic (statistics in this study, [6])
  1. All bicyclists traveling against the direction of traffic flow are at greatly increased risk for accidents; on average they are 3.6 more times at risk than those traveling with traffic
  2. This risk increases for bicyclists who are 17 years old and under-as high as 6.6 times the risk
  3. Because motorists normally scan for traffic traveling in the lawful direction, wrong-way traffic is easily overlooked.
Bicyclist is Traveling on the Sidewalk (statistics in this study, [7])
  1. Only 2 of the 23 bicyclists injured in off-road collisions with motor vehicles in this study were hospitalized; both of these cases involved a cyclist traveling on the sidewalk.

Urban : Non-Intersection Related : In cross traffic

The conflict scenarios for this category include bicyclists who are attempting to ride across oncoming traffic.

The Bicyclist Rides Out from a Residential or Commercial Driveway (statistics in this study, additional, [2])
  1. Commercial Driveway
    • Out of 68 cases, 2.3% of all those crashes were of this type of crash and 22% resulted in serious/fatal injuries
    • There is some kind of vision obstruction in 16% of these crashes
    • This type of crash is more likely to involve youths aged 10-14
  2. Residential Driveway
    • Out of 153 cases, 5.1% of all those crashes were of this type of crash and 24% resulted in serious/fatal injuries
    • This crash is little more severe than the average
    • This type of crash is more likely to involve child bicyclists aged 0-9; more than 50% of these crashes are with bicyclists in this age group
    • Bicyclists aged 10-14 accounted for 85% of this type of crash
    • More than 90% of this type of crash occurred on 2-lane roads
    • More than ⅕ of these crashes involved some type of vision obstruction
The Bicyclist Crosses in Front of Stopped Traffic at a Crosswalk (statistics in this study, [8])
  1. Cyclists are the largest group of slow traffic in conflict with motor vehicles with manoeuvre type 'intersecting' or 'crossing' analyzed in this study
  2. Of all bicycle conflicts with this manoeuvre, 1215 conflicts, approximately 28% of the fatal and 31% of the inpatient crashes happened on a crossing facility (32 and 337 crashes respectively)

Rural

There is significantly less research data available on bicyclist related crashes in rural areas. However, the crash scenarios arising from lack of situational awareness and visual awareness can be presumed be similar to those in urban areas with the additional issue of a lesser number of controlled intersections, high speeds over longer road stretches, less separation distance between different road users and possible lack of designated bicycling infrastructure. Therefore, similar scenarios as urban crashes are presented here and cases where literature are available on rural bicyclist crashes are noted as appropriate.

Rural : At Intersection

This category includes both signal controlled intersections as well as stop sign controlled intersection, 2 way, 4 way and 6 way.

Rural : At Intersection : Parallel to traffic

The conflict scenarios under this category involve bicyclists that are riding along the direction of the vehicular traffic movement.

Motorist Turns Right with Bicyclist to Their Right (statistics in this study, [1])
  1. 51 participants completed a total of 1,071 right-turns, 23 participants could not avoid a crash with a bicyclist in 26 total scenarios
  2. Relative position of a bicyclist, cyclist speed, and the presence of an oncoming vehicle were found to have a statistically significant effect on crash occurrence
    • Bicyclist in front of motorist: in 87% of the cases the motorists fixated on the bicyclist (i.e., actively scanned for the bicyclist before turning right)
    • Bicyclist was approaching from behind in the motorist’s blind zone, in only 44% of the scenarios did a motorist fixate on the bicyclist before turning right
    • Twenty-four crashes occurred with the bicyclist approaching from behind in the motorists’ blind spot and 21 of those crashes occurred in the presence of oncoming left-turning traffic
  3. The motorist did not check for the bicyclist in the mirror before turning in most cases (66% of cases)
  4. Motorist suffered from inattentional blindness (looking but not perceiving bicyclist) in some cases (15% of cases)
  5. Some right turn crashes (19% of cases) were caused due to the motorists’ poor projection, where he/she detected the conflicting bicyclist but did not yield the right-of-way.
  6. Drivers turning right simply focus their attention on the cars coming from the left—those coming from the right posing no threat to them—and fail to see the cyclist from the right early enough
  7. The presence of oncoming vehicles posed more of a threat to the motorist as compared to other objects in his field of view, and as such the motorist spent more time fixating on the oncoming vehicles than on the bicyclist.

Rural : At Intersection : In cross traffic

The conflict scenarios for this category include bicyclists who are attempting to ride across oncoming traffic.

Bicyclist Crashes into Motorist After Riding Out From a Stop Sign (statistics in this study, [2])
  1. Out of 290 cases, 9.7% of those crashes were of of this type of crash and 23% resulted in serious/fatal injury
  2. This type of crash is more likely to involve bicyclists age 0-14 years old
  3. 86% of crashes took place on 2 lane roads
  4. 88% of crashes happened on roads with speeds less than 60 km/h
Bicyclist Did Not Clear the Intersection Before the Light Turned Green for Cross Traffic and the Motorist’s View of the Bicyclist was Obstructed by Standing Traffic (Multi-Lane) (statistics in this study, [2])
  1. Out of 27 cases, (which was 0.9% of all crashes), 15% of cases resulted in serious or fatal injuries
  2. 55% of crashes occurred on high speed (60-70 km/h) or very high speed (80+ km/h) roads
Driver Turning Right and Cyclist Coming from the Right (statistics in this study, [3])
  1. This type of accident occurred in 27 out of 39 accident situations
  2. Drivers turning right continued to look left, the respective proportions of right-looking drivers only being 3% at the same locations.
The Bicyclist Made a Left in Front of Approaching Traffic (statistics in this study, [2])
  1. There were a total of 25 cases- 0.8% of all crashes
  2. 26% of crashes resulted in serious or fatal injuries; it causes a more severe accident than the average
  3. This type of accident is more likely to involve bicyclists aged 0-9 years old
  4. Almost 50% occurred on high-speed (60-70 km/h) and very high speed (80+ km/h) roads combined

Rural : At Intersection : Turning

This category is for the cases where the bicyclist is making a turn across or with the traffic

The Bicyclist Made a Left in Front of Parallel Traffic (statistics in this study, [2])
  1. There were a total of 130 test cases- 4.3% of all crashes
  2. 28% of crashes resulted in serious or fatal injuries; it causes a more severe accident than the average
  3. This type of accident is more likely to involve 10-14 yr old bicyclists
  4. Likely to occur on high-speed, 2 lane roads

Rural : Non-intersection Related

This category includes crashes that happen at midblocks, sidewalks, along on street parking, driveway and any such roadway area that is not an intersection.

Rural : Non-intersection Related : Parallel to traffic

The conflict scenarios under this category involve bicyclists that are riding along the direction of the vehicular traffic movement.

The Bicyclist Rides Too Close to Parked Cars (statistics in this study, [4])
  1. If a crash occurred on the cycle lane and a one-way street, it was most likely this type of crash
  2. In order to prevent this type of crash, bicyclists should be instructed to ride at least one door’s width from parked automobiles, irrespective of whether or not they’re riding on cycle lanes
The Bicyclist Swerves to Avoid an Obstacle (statistics in this study, [5])
  1. An angle collision is the leading crash pattern associated with irregular maneuvers, such as bicycle swerving
The Bicyclist Rides Against the Flow of Traffic (statistics in this study, [6])
  1. All bicyclists traveling against the direction of traffic flow are at greatly increased risk for accidents; on average they are 3.6 more times at risk than those traveling with traffic
  2. This risk increases for bicyclists who are 17 years old and under-as high as 6.6 times the risk
  3. Because motorists normally scan for traffic traveling in the lawful direction, wrong-way traffic is easily overlooked.

Rural : Non-intersection Related : In cross traffic

The conflict scenarios for this category include bicyclists who are attempting to ride across oncoming traffic.

The Bicyclist Crosses in Front of Stopped Traffic at a Crosswalk (statistics in this study, [8])
  1. Cyclists are the largest group of slow traffic in conflict with motor vehicles with manoeuvre type 'intersecting' or 'crossing' analyzed in this study
  2. Of all bicycle conflicts with this manoeuvre, 1215 conflicts, approximately 28% of the fatal and 31% of the inpatient crashes happened on a crossing facility (32 and 337 crashes respectively)

References

  1. Hurwitz, D., Jannat, M., Warner, J., Monsere, C. M., & Razmpa, A. (2015). Towards Effective Design Treatment for Right Turns at Intersections with Bicycle Traffic, http://pdxscholar.library.pdx.edu/cgi/viewcontent.cgi?article=1317&context=cengin_fac, accessed November 2017.
  2. Tan, C. (1996). Crash Type Manual for Bicyclists, FHWA Report, https://www.fhwa.dot.gov/publications/research/safety/pedbike/96104/, accessed November 2017
  3. Summala, H., Pasanen, E., Räsänen, M., & Sievänen, J. (1996). Bicycle accidents and drivers' visual search at left and right turns. Accident Analysis & Prevention, 28(2), 147-153.
  4. Pai, C. W. (2011). Overtaking, rear-end, and door crashes involving bicycles: An empirical investigation. Accident Analysis & Prevention, 43(3), 1228-1235.
  5. Yan, X., Ma, M., Huang, H., Abdel-Aty, M., & Wu, C. (2011). Motor vehicle–bicycle crashes in Beijing: Irregular maneuvers, crash patterns, and injury severity. Accident Analysis & Prevention, 43(5), 1751-1758.
  6. Wachtel, A., & Lewiston, D. (1994). Risk factors for bicycle-motor vehicle collisions at intersections. ITE Journal(Institute of Transportation Engineers), 64(9), 30-35.
  7. Stutts, J. C., & Hunter, W. W. (1999). Motor vehicle and roadway factors in pedestrian and bicyclist injuries: an examination based on emergency department data. Accident Analysis & Prevention, 31(5), 505-514.
  8. SWOV (2010). SWOV Factsheets Crossing Facilities for Cyclists and Pedestrians, https://www.swov.nl/sites/default/files/publicaties/gearchiveerde-factsheet/uk/fs_crossing_facilities_archived.pdf accessed November 2017.
  9. Michigan Bicycle Laws Reference Guide for Law Enforcement Officers [pdf] https://www.michigan.gov/documents/msp/Bike_law_ticket_book_ref_04_press_505969_7.pdf.