2013 Mid-Continent Transportation Research
SymposiumAugust 15, 2013Gateway Hotel
Ames, IA
Evaluation of Mitigation for Safety Concerns on Low Volume, Unpaved Rural Roads in Iowa
Tom McDonald, PE• Iowa Local Technical Assistance Program
• Iowa State University
• (515) 294-6384
Background• Total roads in Iowa ~ 114,000 miles
• State ~9,300• Counties ~90,000• Municipal ~15,000
• Paved ~ 42,000
• Unpaved ~ 72,000 (63%)
• Over one-half of all crashes and almost half of fatalities occur on local roads !
2010 Institute for Transportation Research• Reviewed crash history on 2 lane rural roads in Iowa
• State and local agency• Paved and unpaved
• For local rural, low volume roads• Major crash involvement with younger drivers and higher speeds• In comparing crash performance vs. road characteristics;
• Density, rate, & frequency
• Unpaved roads with traffic volumes of 101-400 vpd identified with poorest safety performance
More study recommended
2011 – 2012 Research Project• Crash mitigation on rural, unpaved roads with traffic volume > 100 vpd
• ~ 4400 miles statewide, (average 44 miles/county)
• Select study segments from central Iowa counties
• Use multi-disciplinary approach to address crash history
• Analyze results of mitigation selected.
Crash Maps
LINN
LEE
SAC
TAMA
IDA
SIOUX CLAY
IOWA
LYON
POLK
CASS
KOSSUTH
PAGE
JASPER
ADAIR
BENTONJONES
DAVIS
CLAYTON
STORY
FAYETTE
CEDAR
CLINTON
BOONE
PLYMOUTH
MONONA
DALLAS
MILLS
FLOYD
SHELBY
OBRIEN
HARDIN
WAYNE
BUTLER
WOODBURY WEBSTER
WRIGHT
MARION KEOKUK
TAYLOR
SCOTT
JACKSON
GREENE
HARRISON
UNION
GUTHRIE
LUCAS
WARREN (2)
JOHNSON
HENRY
DUBUQUE
CRAWFORD CARROLL
MADISON
ADAMS
FRANKLIN
MAHASKA
CALHOUN GRUNDY
POTTAWATTAMIE
HANCOCK
LOUISA
HAMILTON
DECATUR
EMMET
ALLAMAKEEWINNESHIEK
CLARKE
WORTH
PALO ALTO
MARSHALL
HOWARD
FREMONT
DELAWARE
CHEROKEE BREMER
BUCHANAN
RINGGOLD
POWESHIEK
MONROE
MITCHELL
WAPELLO
BUENA VISTA
AUDUBON
BLACK HAWK
VAN BUREN
CHICKASAW
POCAHONTAS
WASHINGTON
APPANOOSE
OSCEOLA
HUMBOLDT
MUSCATINE
JEFFERSON
DICKINSON
DES MOINES
WINNEBAGO
MONTGOMERY
CERRO GORDO
Title/ Text here
STORY (2)
JASPERDALLAS
Selected Study SegmentsSummary of Low Volume Road Segments
2001-2010 Data
County Segment Length ADT *Crashes PDOs Density Rate Severity $ LossStory 550th Ave. 1.99 110 18 11 0.9 2253 22,148 200,337
“ Grant Ave. 2.45 222 29 17 1.02 1461 3,813 44,503“ 19th Street 2.76 202 14 10 0.51 688 4,143 21,014
Madison Holliwell 1.68 260 11 9 0.65 690 885 5,792Jasper N. 39th Ave. 2.95 201 12 6 0.41 554 1,960 7,981
“ W. 4th St. S 1.44 206 15 7 1.11 1385 3,206 66,985
“ E. 5th St. S 1.43 280 14 5 0.63 958 3,568 34,930
Warren 150th Ave. 2.05 281 24 6 0.93 1141 3,030 35,456
“ 118th Ave. 2.75 313 16 8 0.58 509 1,385 8,058“ Nevada St. 3.27 246 7 2 0.21 238 2,191 4,691
Dallas 130th St. 2.79 173 15 9 0.39 851 26,069 140,054“ Bittersweet 4.67 115 11 4 0.23 561 2,735 6,314“ Old Portland 3.38 203 7 5 0.21 280 1,236 2,558
Marshall Smith Ave. 3.5 171 16 10 0.46 732 1,538 7,029“ Marsh Ave. 2.25 150 9 3 0.4 731 2,268 9,071
CR = N / [A x Y x 365 x L] x 100,000,000
Compile Segment Data
Story County, 530th (Grant) from NCL of Ames to SCL of Gilbert, 2.45 mi.
Crash history, 2001 through 2010 (10 years)
29 total crashes, 21 injuries, no fatalities
1 animal
1 ran Stop sign
3 FTYROR (from Stop sign and from uncontrolled intersection)
15 speed related
4 ROR
No adverse surface conditions reported
40 total drivers
22 teenage (55%)
1 +65
1 impaired driver
Objects struck
12 ditch/embankment
Hours of day for crashes
5 from 6:00 through 8:00, 17%
18 from 14:00 through 20:00, 62%
Next Steps
• Meet with local agency officials in counties with selected segments– Determine interest in participating in study– Review crash history and recent safety enhancements
• Engineering, law enforcement, educational efforts– Invite on field review of current conditions– Suggest and select appropriate mitigation
• Engineering, law enforcement, school, and media– Meet with others with potential interest
• Near-by school officials and driver instructors• News media
Field Reviews
• Note higher crash locations, actual and potential
• Perform speed evaluations
• Record conditions on images
• Measure roadway width, document surface and geometric conditions
Speed EvaluationsSequential Detail Report
HI-Star ID: 7552 Begin: Dec/08/11 14:00 End: Dec/12/11 14:00
Street: 130th St Lane: EB Hours: 96.00
State: IA Oper: OOS Period: Sequential
City: Posted: 55 Raw Count: 239
County: Dallas AADT Factor: 1 AADT Count: 60
Gap Time
in Headway
Count Date / Time Advice Speed Length Seconds in Feet Tail Gating
1 2011/12/08 14:09:33.00 Normal 51 MPH 23.00 FT 0 0 No
2 2011/12/08 14:35:03.00 Exceeded Maximum Length 30 MPH 14.00 FT 0 1 Yes
[ Thursday, December 08, 2011 14:00 - 15:00 ]
Raw Count: 2 Average Speed: 40 MPH Average Gap: 0 Occupancy: 0.03 %
Classified Count: 2 Average Length: 18.00 FT
Average Headway: 0 Tailgating Count: 1
3 2011/12/08 15:13:08.00 Normal 55 MPH 12.00 FT 0 2 Yes
4 2011/12/08 15:17:33.00 Normal 52 MPH 18.00 FT 0 0 Yes
5 2011/12/08 15:21:22.00 Normal 44 MPH 16.00 FT 0 0 Yes
6 2011/12/08 15:30:06.00 Averaged Speed Only 47 MPH 32.00 FT 0 0 Yes
7 2011/12/08 15:35:15.00 Exceeded Maximum Length 51 MPH 14.00 FT 0 0 Yes
8 2011/12/08 15:42:40.00 Normal 73 MPH 21.00 FT 0 1 Yes
9 2011/12/08 15:47:19.00 Normal 63 MPH 12.00 FT 0 0 Yes
10 2011/12/08 15:51:17.00 Normal 60 MPH 19.00 FT 0 0 Yes
11 2011/12/08 15:53:48.00 Normal 34 MPH 8.00 FT 0 0 Yes
12 2011/12/08 15:56:47.00 Normal 56 MPH 25.00 FT 0 0 Yes
Speeding violations by Day
130th Street Dallas County
W B E B
(>55) (>65) (>55) (>65)
Sunday 19 5 8 2
Monday 8 3 7 3 AM Count Only
Thursday 9 6 11 3 PM Count Only
Friday 15 6 10 3
Saturday 14 7 7 3
Total 65 27 43 14 # of Violations
Count 301 239 Total Traffic Counted
% Violations. 22% 9% 18% 6%
Use to Select
Enforcement
Periods
Possible Mitigation Considered•Engineering Options:
- Upgrade existing signing- Install delineators with appropriate colors on both sides- Remove or relocate roadside obstacles- Remove or trim existing vegetation in clear zone
•Law enforcement Options:- Periodic patrols at high crash/violation times- Monitor speeds with recording devices- Monitor seat belt use- Occasional visits with driver instructors in high schools where appropriate
•Educational Options- Article in local newspaper occasionally (annual?)- Annual presentation to new drivers in high school drivers ed. classes
o Engineer, law enforcement, or LTAP
Examples of Mitigation AppliedPotential Mitigation Strategies
County Dallas Jasper Jasper Story Story WarrenRoute 130th Street W 4th St. S E 5th St. S 530th Avenue 550th Avenue 150th Avenue
Mitigation Strategy Proposed Employed Proposed Employed Proposed Employed Proposed Employed Proposed Employed Proposed Employed
Highly Reflective Signs X X X X X X X X X X X X
Remove Vegetation X X X
Reduce Speed Limit X X X X
Add Delineators X X X X X X X X
Review Crash Clusters X
TCD - Flags, Chevron & Cross Traffi c X X X X X
Additional Enforcement X X X X X X X X
News Media Release X X X X
Meet w/High School Offi cials X X X X X X X X
Engineering Strategies
Law Enforcement Documentation of Enhanced Law Enforcement Activities
LVSR II Project March - May 2013 Agency- Story County Sheriff's Office530th (Grant) Avenue
Time Spent Time Stationary (S) Number Vehicles Improper CitationsDate Start Stop (Hrs) Mobile (M) Encountered Actions Noted Issued3/15/2013 7 am 9 am 2 S 13 2 03/18/2013 7 am 9 am 2 S + M 4 2 13/24/2013 3 pm 5 pm 2 S 16 1 04/6/2013 1 pm 3 pm 2 S + M 22 0 04/12/2013 3 pm 5 pm 2 S 35 0 04/14/2013 1 pm 3 pm 2 S + M 18 0 04/25/2013 3 pm 5 pm 2 S 67 0 04/29/2013 7 am 9 am 2 S + M 13 2 05/10/2013 3 pm 5 pm 2 S 19 2 25/12/2013 1:30 pm 3:30 pm 2 S + M 13 0 0
550th AvenueTime Spent Time Stationary (S) Number Vehicles Improper Citations
Date Start Stop (Hrs) Mobile (M) Encountered Actions Noted Issued3/16/2013 3 pm 5 pm 2 S + M 6 2 03/21/2013 3 pm 5 pm 2 S 22 0 03/29/2013 3 pm 5 pm 2 S 14 0 04/4/2013 3 pm 5 pm 2 S 12 0 04/8/2013 7 am 9 am 2 S + M 15 2 14/20/2013 7 am 9 am 2 S 5 0 04/26/2013 1 pm 3 pm 2 S 3 0 04/28/2013 3 pm 5 pm 2 S 11 0 05/8/2013 7 am 9 am 2 S + M 8 0 0
News ReleaseNews Release
In December of 2010, Iowa State University released a study titled “Safety Analysis of Low Volume Rural Roads in Iowa”. Several conclusions in that report emphasized the much higher crash rates and densities for many types of the crash events taking place on unpaved rural roads with traffic counts between 100 and 400 vehicles per day. Using the information gleaned from that investigation and report, a follow up study was begun in the fall of 2011 to review some typical area roads that fall in that category. Field reviews of several road segments in Story and nearby counties were conducted, possible crash causes noted and suggestions made for possible physical improvements made to clear delineate the roadside, if appropriate. A second phase of this study is to attempt to find possible other mitigation strategies that could possibly be used to reduce those high crash rates noted.
Two short road segments in Story County were originally identified as study sites, and after conducting field reviews and speed studies and also holding discussions with local engineering and law enforcement officials, two strategies have been now been chosen to be employed. First, all existing signs along the routes will be replaced with ones of higher reflective value and secondly, additional enforcement will be employed for a period of time to hopefully slow traffic and also to help identify typical driver traits and actions that might account for the higher crash numbers that have been recorded rates noted. The Story County Sheriff’s Office will be begin conducting that additional enforcement this Friday and it will be continued for approximately two months.
An analysis of before and after crash data is planned, but only after the improvements and enforcement have been in place for a two to three years. The original safety analysis report may be viewed on the Institute for Transportation website at http://www.intrans.iastate.edu/reports/souleyrette_low_vol_report_w_cvr.pdf
Meeting with High School Officials• Principal, driver educator, school bus supervisor
• County engineer and deputy, Governors Traffic Safety Bureau, LTAP researchers
• Shared general data from school district crashes & specific information about study segment
• Discussed on-going and future plans of school district for addressing student driver safety
Findings
• When high school was in close proximity, student drivers are involved in crashes to a significant extent
• Speed also a major contributor to many crashes• Identifying other reliable contributors difficult on these roads • Multi-disciplinary approach to crash mitigation can be
effective• Larger study sample across state may yield differing results• Insufficient time with this study to fully evaluate results
Volume vs. Frequency ??
110 115 150 171 173 201 202 203 206 222 246 260 280 281 3130
5
10
15
20
25
30
35
50 100 150 200 250 300 3500
5
10
15
20
25
30
35
Traffic Volumes
cras
hes
Recommendations
• Undertake expanded study to consider more samples across a broader area of the state
• Promote study for reducing statutory 55 mph speed limit on unpaved roads, statewide or on higher crash segments
• Post regulatory speed limit intermittently on unpaved roads with higher crash frequencies
• Include mandatory minimum experience and instruction for operating a motor vehicle on unpaved roads in new driver training
• Take advantage of multi-disciplinary opportunities to address crashes on unpaved rural roads
Questions
Top Related