Transcript Slide 1
SAFETY CONSIDERATIONS
HOV FACILITIES AND MANAGED LANES IN HOUSTON Suhag Kansara Ned Levine, PhD
Houston-Galveston Area Council TRB Conference on HOV and Managed Lanes Houston, TX April 18, 2005
Purpose
• Document crashes on HOV lanes • Compare safety of HOV lanes with General
Purpose freeway lanes
• Identify characteristics of HOV crashes
Data sources
• METRO HOV crash data 2001-2004 • DPS freeway crash data 1999-2001
HOV Corridors in Houston Region
HOV Crashes 2001-2004
100 75 50
Central Houston HOV Crashes: 2001-2004 METRO Database
150 125
2001 2002
Year
2003 2004
Crashes by time of day: 2001 45.0% 40.0% 35.0% 30.0% 25.0% 20.0% 15.0% 10.0% 5.0% 0.0% 12-4AM
HOV Lanes Freeways
4-8AM 8-12PM 12-4PM
Time Period (Four Hrs)
4-8PM 8-12AM
HOV Crashes 2001
50 40 30 20 10 0 IH 10 W HOV Crashes by Freeway: 2001 Metro Database US 290 IH 45 N US 59 N
F reew ay
IH 45 S US 59 S
Crashes on HOV segments
Crashes on Freeway segments
Crash risk: HOV vs. Freeway lanes
200 HOV Crash Risk: 2001 Crashes Per 100 Million VMT
Freeway crashes HOV crashes
150 100 50 0 IH 10 W US 290 IH 45 N US 59 N
F reew ay
IH 45 S US 59 S
Multiple Crash Locations
Multiple Crash Locations – large scale
Hot-spot locations
HOV lanes merging to freeway lanes
Hot-spot locations
Direct access ramps merging with HOV lanes from park and ride lots
Junction related HOV crashes
Hot-spot locations
Design compromises in geometrical structure of HOV lane – shoulder width
Contributing factors • Single vehicle crashes
HOV facility Freeway facility 30% 24%
• Speeding
HOV facility Freeway facility 53% 56%
• Following too close
HOV facility Freeway facility 5% 3%
Tentative conclusions • HOV lanes are safe • Design compromises can increase crash risk • Trade-off safety between barrier facilities vs.
diamond lanes
Future research • Compare barrier facilities with diamond lanes • Who is involved in the crashes – Disproportionate number of males – Disproportionate number of persons in their
30’s and 40’s
• Do certain groups have more difficulty with
barrier facility?
For more information, see: http://www.h-gac.com/safety
Thank You