Post on 15-Aug-2020
WA
MTME
ND
SD
WY
WI
IDVTMNOR
NH
IA
MA
NE
NY
PA
CT RI
NJ
INNV
UTCA
OHIL
DE
WV MDCO
KYKS VA
MO
AZ OK
NCTN
TX
NM
ALMSGA
SCAR
LA
FL
MI
AK
HIRoundabouts
2015
Roundabouts per State01 - 2526 - 5051 - 100101 - 200201 - 400
WA
MTME
ND
SD
WY
WI
IDVTMNOR
NH
IA
MA
NE
NY
PA
CT RI
NJ
INNV
UTCA
OHIL
DE
WV MDCO
KYKS VA
MO
AZ OK
NCTN
TX
NM
ALMSGA
SCAR
LA
FL
MI
AK
HIRoundabouts
1995
Roundabouts per State01 - 2526 - 5051 - 100101 - 200201 - 400
WA
MTME
ND
SD
WY
WI
IDVTMNOR
NH
IA
MA
NE
NY
PA
CT RI
NJ
INNV
UTCA
OHIL
DE
WV MDCO
KYKS VA
MO
AZ OK
NCTN
TX
NM
ALMSGA
SCAR
LA
FL
MI
AK
HIRoundabouts
2000
Roundabouts per State01 - 2526 - 5051 - 100101 - 200201 - 400
WA
MTME
ND
SD
WY
WI
IDVTMNOR
NH
IA
MA
NE
NY
PA
CT RI
NJ
INNV
UTCA
OHIL
DE
WV MDCO
KYKS VA
MO
AZ OK
NCTN
TX
NM
ALMSGA
SCAR
LA
FL
MI
AK
HIRoundabouts
2005
Roundabouts per State01 - 2526 - 5051 - 100101 - 200201 - 400
WA
MTME
ND
SD
WY
WI
IDVTMNOR
NH
IA
MA
NE
NY
PA
CT RI
NJ
INNV
UTCA
OHIL
DE
WV MDCO
KYKS VA
MO
AZ OK
NCTN
TX
NM
ALMSGA
SCAR
LA
FL
MI
AK
HIRoundabouts
2010
Roundabouts per State01 - 2526 - 5051 - 100101 - 200201 - 400
WA
MTME
ND
SD
WY
WI
IDVTMNOR
NH
IA
MA
NE
NY
PA
CT RI
NJ
INNV
UTCA
OHIL
DE
WV MDCO
KYKS VA
MO
AZ OK
NCTN
TX
NM
ALMSGA
SCAR
LA
FL
MI
AK
HIRoundabouts
All
Roundabouts per State01 - 2526 - 5051 - 100101 - 200201 - 400
Roundabouts201 - 400
WA
MTME
ND
SD
WY
WI
IDVTMNOR
NH
IA
MA
NE
NY
PA
CT RI
NJ
INNV
UTCA
OHIL
DE
WV MDCO
KYKS VA
MO
AZ OK
NCTN
TX
NM
ALMSGA
SCAR
LA
FL
MI
HI 1990
Roundabouts per State01 - 2526 - 5051 - 100101 - 200
AK
AK
HI
All
Roundabouts per County01-45-1112-1920-3031-106
Status of Roundabouts in North America, 2017 EditionA Snapshot of the Online Database at roundabouts.kittelson.comMaintained voluntarily on behalf of the TRB Committee on Roundabouts
New Website – Please Help Us Keep This Database Current!
Data sources: Everyone (Thank you!)Database programming: Ian CameronQuality control team: Lee Rodegerdts, Pete Jenior, Matt Kittelson, Scott BeairdAnalysis: Lee RodegerdtsGIS graphics: Jon SommervillePoster layout: Ralph Bentley
Growth over Time
Known Roundabouts in the U.S.
Why No Maps of Canada This Time?• Database is known to be very incomplete (158 sites)• At least 400 roundabouts believed to exist, but few additions
to database since 2014 – your help is needed!
Estimated U.S. roundabouts
through 2016: 4,200
Number of Approaches
Analysis and Methodology
By State
By County
Lane Type
1990
20151995
2010
2000
2005
Previous Control Methods and Assumptions• Data pulled April 15, 2017
• Other circular intersections excluded
• Current database compared to what was known in 2014, 2011, 2008, and 2003 to estimate undercounting
• Total estimated unknown sites in 2016: 29% (40% in 2013)
• Unknown sites are distributed over multiple years, biased towards most recent years
TRANSPORTATION RESEARCH BOARD5th International Conference on RoundaboutsMay 8-10, 2017, Green Bay, Wisconsin
Presented byLee A. Rodegerdts, PE
lrodegerdts@kittelson.com
2approaches
0.8%
4approaches
63.8%
3approaches
32.6%
5–8approaches
2.9%
Mini1%
Multilane28%
Single Lane70%
All-Way Stop3.4%
None (new)22.2%
One-/Two-Way Stop
15.4%
Other1.0% Signal
4.2%
Unknown53.7%
Credits–
0
50
100
150
200
250
300
350
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
Roun
dabo
uts
per Y
ear
Known or Estimated Year Assumed Unknown Site
Annual
0
500
1000
1500
2000
2500
3000
3500
4000
4500
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
Cum
ulat
ive
Roun
dabo
uts
Known or Estimated Year Assumed Unknown Site
Cumulative
roundabouts.kittelson.com