safety considerations hov facilities and managed lanes in houston suhag kansara ned levine, phd...
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SAFETY CONSIDERATIONS
HOV FACILITIES AND MANAGED LANESIN HOUSTON
Suhag KansaraNed Levine, PhD
Houston-Galveston Area CouncilTRB Conference on HOV and Managed Lanes
Houston, TXApril 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
2001 2002 2003 2004
Year
50
75
100
125
150
HO
V c
ras
he
s
Central Houston HOV Crashes: 2001-2004METRO Database
HOV Crashes 2001-2004
Crashes by time of day: 2001
IH 10 W US 290 IH 45 N US 59 N IH 45 S US 59 S
Freeway
0
10
20
30
40
50
HO
V c
rash
es
HOV Crashes by Freeway: 2001Metro Database
HOV Crashes 2001
Crashes on HOV segments
Crashes on Freeway segments
IH 10 W US 290 IH 45 N US 59 N IH 45 S US 59 S
Freeway
0
50
100
150
200
HO
V c
rash
ris
k
HOV Crash Risk: 2001Crashes Per 100 Million VMT
Freeway crashes
HOV crashes
Crash risk: HOV vs. Freeway lanes
Multiple Crash Locations
Multiple Crash Locations – large scale
Hot-spot locations
HOV lanes merging to freeway lanes
Direct access ramps merging with HOV lanes from park and ride lots
Hot-spot locations
Junction related HOV crashes
Design compromises in geometricalstructure of HOV lane – shoulder width
Hot-spot locations
Contributing factors
• Single vehicle crashesHOV facility 30%
Freeway facility 24%
• SpeedingHOV facility 53%Freeway facility56%
• Following too closeHOV facility 5%
Freeway facility 3%
• HOV lanes are safe
• Design compromises can increase crash risk
• Trade-off safety between barrier facilities vs. diamond lanes
Tentative conclusions
• 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?
Future research
For more information, see:
http://www.h-gac.com/safety
Thank You