Safety at Unsignalized Intersections Safety at Unsignalized - PowerPoint PPT Presentation

Safety at Unsignalized Intersections Safety at Unsignalized Intersections Unsignalized Intersections

FHWA Safety Focus Areas FHWA Safety Focus Areas Unsignalized Intersections Unsignalized Intersections 2

National Statistics National Statistics Unsignalized Intersections Unsignalized Intersections 3

National Statistics National Statistics There were 41,059 highway fatalities There were 41,059 highway fatalities in 2007. Where did they occur? in 2007. Where did they occur? Non-Intersections 79% Intersections 21% About half of all all crashes and crashes and About half of half of all injury crashes half of all injury crashes occur at intersections. occur at intersections. Unsignalized Intersections Unsignalized Intersections 4

Intersection Fatalities Intersection Fatalities There were 8,657 intersection fatalities in 2007. There were 8,657 intersection fatalities in 2007. Where did they occur? Where did they occur? 6,000 5,232 5,000 39% in 39% in rural areas rural areas 4,000 Fatalities 3,000 2,000 1,739 61% in 61% in 1,472 urban areas urban areas 1,000 214 0 Arterial Collector Local Unknown Unsignalized Intersections Unsignalized Intersections 5

Intersection Fatalities Intersection Fatalities Unsignalized Intersections Unsignalized Intersections 6

Intersection Safety Guidance Intersection Safety Guidance • NCHRP Report 500 Volume 5 • Guide sheets • Safety Strategies brochure Unsignalized Intersections Unsignalized Intersections 7

Typical Intersection Crash Types Typical Intersection Crash Types • Right angle • Rear end • Left turn • Sideswipe • Pedestrian/bicycle Unsignalized Intersections Unsignalized Intersections 8

Crash Reduction Factors Crash Reduction Factors • Quantitative results from research or other studies • Expected reduction in crashes from implementation of a specific countermeasure Unsignalized Intersections Unsignalized Intersections 9

Angle Crashes Angle Crashes • Account for 53% of fatal crashes at unsignalized intersections • Potential countermeasures: – Clear sight triangles – Improve awareness of intersection – Apply access management – Improve turn lane design – Construct roundabouts – Construct acceleration lanes – Close/relocate intersections – Reduce/eliminate skew – Post appropriate speed limits – Targeted enforcement Unsignalized Intersections Unsignalized Intersections 10

Clear Sight Triangles Clear Sight Triangles Unsignalized Intersections Unsignalized Intersections 11

Improve Awareness of Intersection Improve Awareness of Intersection Double Warning Signs Oversize Signs Unsignalized Intersections Unsignalized Intersections 12

Improve Awareness of Intersection Improve Awareness of Intersection Splitter Island Supplemental Beacons Unsignalized Intersections Unsignalized Intersections 13

Improve Awareness of Intersection Improve Awareness of Intersection Provide Lighting Install Rumble Strips Unsignalized Intersections Unsignalized Intersections 14

Apply Access Management Apply Access Management Right-in/Right-Out Channelization Unsignalized Intersections Unsignalized Intersections 15

Improve Turn Lane Design Improve Turn Lane Design Offset Right Turn Lane Unsignalized Intersections Unsignalized Intersections 16

Construct Roundabouts Construct Roundabouts Unsignalized Intersections Unsignalized Intersections 17

Construct Left- -Turn Acceleration Lanes Turn Acceleration Lanes Construct Left Through Lanes Acceleration Lane Unsignalized Intersections Unsignalized Intersections 18

Close / Relocate Intersection Close / Relocate Intersection Unsignalized Intersections Unsignalized Intersections 19

Reduce/Eliminate Skew Reduce/Eliminate Skew New alignment New alignment Unsignalized Intersections Unsignalized Intersections 20

Post Appropriate Speed Limits on Approaches Post Appropriate Speed Limits on Approaches Unsignalized Intersections Unsignalized Intersections 21

Targeted Enforcement Targeted Enforcement Speed violations Stop violations Unsignalized Intersections Unsignalized Intersections 22

Rear End Crashes Rear End Crashes • Account for 6% of fatal crashes at unsignalized intersections • Potential countermeasures: – Install turn lanes – Supplemental overhead signing – Provide shoulder bypass lanes – Provide pavement markings – Provide right-turn acceleration lanes – Construct roundabouts* – Provide left-turn acceleration lanes* – Provide lighting* – Post appropriate speed limits* – Improve intersection awareness* * Discussed previously Unsignalized Intersections Unsignalized Intersections 23

Install Turn Lanes Install Turn Lanes Left turn lanes Right turn lanes Unsignalized Intersections Unsignalized Intersections 24

Supplemental Overhead Signing Supplemental Overhead Signing Unsignalized Intersections Unsignalized Intersections 25

Provide Shoulder Bypass Lanes Provide Shoulder Bypass Lanes Unsignalized Intersections Unsignalized Intersections 26

Provide Pavement Markings Provide Pavement Markings Unsignalized Intersections Unsignalized Intersections 27

Provide Right- -Turn Acceleration Lanes Turn Acceleration Lanes Provide Right Unsignalized Intersections Unsignalized Intersections 28

Left Turn Crashes Left Turn Crashes • Account for 8% of fatal crashes at unsignalized intersections • Potential countermeasures: – Improve turn lane design – Implement turn restrictions – Use indirect left turn treatments – Provide lighting* – Clear sight triangles* – Provide left turn acceleration lanes* – Construct roundabouts* – Close/relocate high-risk intersections* * Discussed previously Unsignalized Intersections Unsignalized Intersections 29

Improve Turn Lane Design Improve Turn Lane Design Unsignalized Intersections Unsignalized Intersections 30

Improve Turn Lane Design Improve Turn Lane Design Unsignalized Intersections Unsignalized Intersections 31

Implement Turn Restrictions Implement Turn Restrictions Unsignalized Intersections Unsignalized Intersections 32

Use Indirect Left Turn Treatments Use Indirect Left Turn Treatments Unsignalized Intersections Unsignalized Intersections 33

Sideswipe Crashes Sideswipe Crashes • Account for 2% of fatal crashes at unsignalized intersections • Potential countermeasures: – Install pavement markings – Provide lane assignment signing or marking – Provide right-turn acceleration lanes* * Discussed previously Unsignalized Intersections Unsignalized Intersections 34

Provide Striping in Median Area Provide Striping in Median Area Unsignalized Intersections Unsignalized Intersections 35

Lane Assignment Signing/Marking Lane Assignment Signing/Marking Unsignalized Intersections Unsignalized Intersections 36

Pedestrian/Bicycle Crashes Pedestrian/Bicycle Crashes • Account for 14% of fatal crashes at unsignalized intersection crashes • Potential countermeasures: – Improve pedestrian/bicycle facilities – Provide traffic calming – Information and education Unsignalized Intersections Unsignalized Intersections 37

Improve Pedestrian/Bicycle Facilities Improve Pedestrian/Bicycle Facilities Advance crossing warning Continuous/Setback Sidewalks Unsignalized Intersections Unsignalized Intersections 38

Provide Traffic Calming Provide Traffic Calming Neighborhood circles Pedestrian bulb-outs Unsignalized Intersections Unsignalized Intersections 39

Information and Education Information and Education Web sites Web sites Web sites Printed material Printed material Printed material In school programs In school programs In school programs Radio and TV Radio and TV Radio and TV Community outreach Community outreach Community outreach Speed trailers Speed trailers Speed trailers Unsignalized Intersections Unsignalized Intersections 40

For More Information For More Information • AASHTO Report 500 Series Volume 5 – http://safety.transportation.org/ • Manual on Uniform Traffic Control Devices – http://mutcd.fhwa.dot.gov/ • Toolbox on Intersection Safety and Design – http://www.ite.org/ • FHWA Office of Safety – http://safety.fhwa.dot.gov/ Unsignalized Intersections Unsignalized Intersections 41