PROJECT CASE STUDY

Data-Driven 

Safety Analysis

Systemic Planning Process Benefits Missouri Pavement Project

Historically, the Missouri Department of Transportation (MoDOT) only painted centerline and edge line stripes on 

routes with 1,000 or greater daily traffic volume. Routes with annual average daily traffic (ADT) of less than 1,000 

only received a centerline stripe.

As part of a 2008 edge line striping program for High Risk Rural Roads (HRRR), MoDOT performed a systemic 

safety analysis on all state-owned roadways without a painted edge line, over 18,000 centerline miles. They 

found that more than two-thirds of severe crashes were occurring on roadways carrying 400 to 1,000 in ADT. 

MoDOT was interested in improving safety on these routes because they represented a system of roadways 

that had a large number of the severe crashes. The agency took a proactive safety approach and painted 

edge lines on all 7,500 miles that fell in this ADT range, even though many of these roads had never had a 

severe crash. The results so far have shown a 15 percent decrease in total crashes.

Safety Tools Used

MoDOT evaluated the results of adding edge line pavement 

markings by performing a “before and after” comparison 

on 570 miles of rural, two-lane state highways using their 

Countermeasure Evaluation Tool. MoDOT developed the 

Countermeasure Evaluation Tool as a customized spreadsheet 

that incorporates Empirical Bayes methodology to estimate the 

effectiveness of an implemented countermeasure. 

MoDOT compared the expected number of crashes with and 

without the edge line treatment for the three years before the 

installation of the edge lines in 2009 to the two years after the 

installation. Data input into the spreadsheet included segment 

beginning and end mile posts, annual ADT, crash frequencies for 

each segment (non-intersection), and roadway type (rural twolane, undivided). 

Overall Effectiveness Various Counties

Security Level Total F & DI

` Observed Crashes Before Period 576 105

` Observed Crashes After Period 327 46

` Effectiveness (% Change) 15.18 19.30

` Direction of Change Decrease Decrease

` Significance Significant at 95% 

confidence level

Not significant at 90% 

confidence level

SYSTEMIC SAFETY 

ANALYSIS BENEFITS

Improved Safety

Systemic analysis can be applied to rural 

roadways where a significant number of 

crashes happen over a wide area.

Informed Decision-Making

Systemic analysis helps determine where 

safety countermeasures can be used 

most effectively.

Optimized Investment

Funding can be directed to the projects 

and locations that will produce the most 

safety benefit per dollar.

(Source: MoDOT)
Every Day Counts (EDC), a State-based initiative of FHWA’s Center for Accelerating 

Innovation, works with State, local and private sector partners to encourage the adoption of 

proven technologies and innovations aimed at shortening and enhancing project delivery

www.fhwa.dot.gov/everydaycounts

For additional 

information, 

please contact:

Along the 570 miles that were compared, the 

combined study locations showed that the new edge 

line stripe was very effective at reducing not only the 

total crashes, but also the run-off-road right crash type. 

The analysis revealed a 15.2 percent decrease in total 

crashes, for all crash types, after the countermeasure 

was implemented. 

The findings were significant at a 95 percent 

confidence level, indicating a high degree of certainty 

that the edge lines contributed to the reduction. The analysis also found a 19.3 percent decrease in severe 

crashes after the countermeasures were implemented; however, the relatively low density of injury crashes 

prevented the result from being statistically significant.

FHWA-14-CAI-056

Key Takeaway

` Systemic safety analysis can be very helpful 

in states with an extensive rural and/or 

local roadway network, or when interested 

in a particular crash type (e.g., roadway 

departure or pedestrians).

Jerry Roche

FHWA Office of Safety

515-233-7323

Jerry.Roche@dot.gov

John McFadden

FHWA Resource Center 

410-962-0982

John.Mcfadden@dot.gov

Conclusions

MoDOT’s use of systemic safety analysis for project evaluation led to implementation of a low-cost 

countermeasure that reduced crashes on low-volume roads with low-crash frequency and density. While 

the results were stronger for total crashes, there was still a net reduction in fatal and severe injury crashes on 

improved corridors. 

Agencies can employ this type of analysis to make the most efficient use of limited funds in deciding whether 

to continue or discontinue funding or to implement a particular countermeasure for specific crash types and 

locations. It allows funds to be directed to the projects and locations that will produce the most benefit in terms 

of reduced crashes for the least investment.

ADDITIONAL RESOURCES

` Further details on MoDOT’s systemic analysis process are available at 

http://safety.fhwa.dot.gov/systemic/mo.htm

` More information on Data-Driven Safety Analysis is available on the Every Day Counts website at 

http://www.fhwa.dot.gov/everydaycounts/edc-3/analysis.cfm

Route M in Boone County before (left) and after (right) adding edge line pavement markings. (Photo courtesy Missouri DOT)