U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590

Skip to content
Facebook iconYouTube iconTwitter iconFlickr iconLinkedInInstagram

Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations

This magazine is an archived publication and may contain dated technical, contact, and link information
Back to Publication List        
Publication Number:  FHWA-HRT-15-048    Date:  June 2015
Publication Number: FHWA-HRT-15-048
Date: June 2015


Safety Evaluation of Centerline Plus Shoulder Rumble Strips

Chapter 8. Economic Analysis

For the purposes of the economic analysis, the assumed treatment is, conservatively, the dual application of CLRS and SRS for which the combined CMF of 0.800 for total crashes (table 8) is recommended. Treatment costs used range from $3,000/mi for Missouri to $12,000/mi in Kentucky. Service lives are 7-10 and 12-15 years, respectively. Results are presented for these two extremities.

The FHWA Office of Safety R&D suggests that the Office of Management and Budget Circular A-4 be used to determine the conservative real discount rate of 7 percent that was applied to calculate the annual cost of the treatment for 7- and 12-year service lives, respectively. Applying the lower ends of the service life ranges conservatively gives annual costs of $557 and $1,511/mi for the two cost/service life extremes.

The most recent FHWA mean comprehensive crash costs disaggregated by crash severity, location type, and speed limit are based on 2001 dollar values.(8) The 2001 unit costs for property damage only (PDO) and FI crashes from the FHWA report ($7,428 and $158,177) were multiplied by the ratio of the 2014 value of a statistical life of $9.2 million to the 2001 value of $3.8 million.(7,8) Applying this ratio of 2.42 to the unit costs for PDO and FI crashes, and then weighting by the frequencies of these two crash types in the after period, an aggregate 2014 unit cost for total crashes of $162,045 was obtained. Fatal crashes were not considered on their own because of the very low numbers of such crashes in the data, which would skew the results.

The total crash reduction was calculated by subtracting the actual crashes in the after period from the expected crashes in the after period had the treatment not been implemented. The number of crashes saved per mile-year was 0.1881, which was obtained by dividing the total crash reduction (482.0) by the number of after period mile-years per site (2,562).

The annual benefit (i.e., crash savings) of $30,481 is the product of the crash reduction per mile-year (0.1881) and the aggregate cost of a crash (all severities combined) ($162,045). The B/C ratio is calculated as the ratio of the annual benefit per mile to the annual cost per mile. The B/C ratios are estimated to be 20.2 for the higher cost/higher service life assumption and 54.7 for the lower cost/lower service life assumption. These results suggest that the treatment, even in its most expensive variation, can be highly cost effective.



Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000
Turner-Fairbank Highway Research Center | 6300 Georgetown Pike | McLean, VA | 22101