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

• tmcdonal@iastate.edu

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