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 report is an archived publication and may contain dated technical, contact, and link information
Publication Number: FHWA-HRT-09-061
Date: February 2010

Simulator Evaluation of Low-Cost Safety Improvements on Rural Two-Lane Undivided Roads: Nighttime Delineation for Curves and Traffic Calming for Small Towns

PDF files can be viewed with the Acrobat® Reader®


For calming traffic in small towns, the results of the current experiment identified two relatively low-cost safety solutions as being worthy of further study and consideration: (1) providing for and encouraging parking in the town and (2) adding painted chicanes to the town entrances. However, the above results have not been validated in the field. As noted previously, simulations of driving through small towns do not take into account all hazardous factors involved in driving through real small towns. In order to achieve adequate field validation, several recommendations are suggested on how to proceed with these two potential solutions.


Adding parking to both sides of the main street in the town was an effective traffic-calming technique in this experiment. However, a field test in a small rural town should be conducted with cars parked on the main street both during the day and at night. If the town has present parking spaces which are underutilized, cars could be artificially introduced by renting a number of used cars from an automobile dealer and/or by parking rarely used private or public vehicles on the main road for a specified duration (several weeks, months, etc.). The density of parked cars could be changed radically from a normal sparse parking density to an experimentally introduced high parking density. As was suggested for streaming PMDs, a before/after/before field test might be devised where driving speed and deceleration would be measured both before and in the town. Such measurements would be made before the implementation of an increased density of parked cars had been put in place, during such an experimental implementation, and after the parked cars had been removed. A baseline speed, followed by a significant decrease in speed during the treatment and a return to the baseline would be the measure of success.

If the field test proved successful, long-term implementation might be attempted to create a higher density of parked cars in the town during times when traffic calming is most needed. A campaign might be launched to encourage more parking at appropriate times. Businesses and government entities could be encouraged to park cars on the main street instead of in parking lots and driveways. Public events and town meetings could specify parking on the main street. Public service and utility trucks could be requested to park on the main street when not in use. Such an increase in the number of parked cars is likely to be a very low-cost option if underutilized parking spaces are already available in the town or if parking can be easily implemented without any changes to the width of the main street or to any curb and gutter layout which might be present.

In the suggested field test scenarios using parked cars, especially in cases of only one travel lane in each direction, special attention needs to be given to assessing and balancing the possible safety hazards of vehicles, drivers, passengers, and pedestrians spontaneously entering the roadway. An additional consideration is the accommodation of bicycle traffic. Although the parked cars condition proved successful in slowing drivers down in the simulator, the suggestion to implement a parked cars solution in the real world needs further investigation.

Painted Chicanes

Based on the results of the current experiment, the most cost-effective solution for traffic calming in small towns is using painted chicanes. For extremely small towns (under 1,000 people), this may be the only affordable traffic-calming implementation. If the main street were wide enough at the beginning and end of the town or if some parking spaces could be eliminated at these locations, painted chicanes might be implemented with minimal cost. A small town might be selected which possesses these necessary characteristics. Painted chicanes could be implemented on an experimental basis. A before/after field test might be conducted where deceleration and speed were measured through the town. If a somewhat longer experimental "after" period were employed (e.g., 3 months) after 1 month of only painted chicanes, flexible vertical yellow delineators could be added to the painted chicanes for the second month and then removed for the third month. In this way, flexible yellow delineators could be tested for their ability to deter drivers from cutting the corners on the painted chicanes.

The recommended field test is only of the before/after design because it might be difficult to remove the pavement paint once applied. Also, if effective, continued implementation would prolong possible benefits. In the current experiment, the painted chicanes were effective in slowing down traffic at the beginning and end of the town. However, between the chicanes in the middle of the town, drivers tended to accelerate and drive at higher speeds. A combination of the parked cars and painted chicanes solutions could prove beneficial in this regard. If a higher density of parking could be encouraged even only in the middle portion of the town, the complementary advantages of both treatment types might be realized. This combination might be tested in a second field study in a different town.

In the above suggested field test scenarios using painted chicanes, especially in cases without a separating median, attention needs to be given to assessing and balancing the possible safety hazards of head-on or sideswipe opposite-direction crashes. In general, both bulb-outs and chicanes should only be implemented in well lit areas.


The current experiment focused on two areas: (1) advanced detection and speed reduction for curves in rural two-lane roads at night and (2) traffic calming for small rural towns during the day. For curves, PMDs with edge lines performed better in terms of slowing drivers down than pavement markings alone. The streaming PMDs solution with edge lines offered the most dramatic potential benefit in terms of advanced curve detection, and it is worthy of further study and consideration. In towns, chicanes slowed drivers down the most followed by parked cars on both sides of the road. As possible low-cost safety improvements (provided adequate field validation), adding painted chicanes to town entrances and providing and encouraging parking in the town are worthy of further study and consideration.


This experiment was conducted by the joint effort of many individuals and organizations. The authors wish to acknowledge valuable contributions from the following individuals: Raymond Krammes, Roya Amjadi, and Carol Tan for guidance and insight; Thomas Granda for oversight and support; Paul Tremont, William Perez, and Stephen Fleger for management and review; Pascal Beuse for data analysis, graphics, and editing; Lindsey Clark and Dana Duke for laboratory support; and FHWA HDS staff members Barry Wallick, Jason Williams, Peter Chou, Ryan Cartwright, and Michael Baumgartner for creating and sustaining the driving simulation. Thomas Welch from the Iowa Department of Transportation and Thomas Broderick from the Massachusetts Highway Department provided information on speed calming in small towns. Gilbert Soles from the Florida Department of Transportation provided information on streaming light patterns for roadway delineation. The authors also wish to acknowledge valuable contributions from the following organizations: the FHWA Turner-Fairbank Highway Research Center for providing laboratory facilities and staff and the Technical Advisory Committee for the Low Cost Safety Improvements Pooled Fund Study for providing input and direction from the perspective of engineering practice.


1. National Highway Traffic Safety Administration. (2007). Fatality Analysis Reporting System, U.S. Department of Transportation, Washington, DC. Obtained from: http://www.fars.nhtsa.dot.gov. Site last accessed October 23, 2009.

2. Fitzpatrick, K., Balke, K., Harwood, D.W., and Anderson, I.B. (2000). "Accident Mitigation Guide for Congested Rural Two-Lane Highways," NCHRP Report 500 Series, Vol. 440,Transportation Research Board, Washington, DC.

3. National Highway Traffic Safety Administration. (2005). Speed Management Strategic Initiative, DOT-HS-809-924, U.S. Department of Transportation, Washington , DC.

4. National Cooperative Highway Research Program. (2003). "Guidance for Implementation of the AASHTO Strategic Highway Safety Plan," NCHRP Report 500 Series, Transportation Research Board, Washington, DC.

5. Transportation Pooled Fund. (2009). Transportation Pooled Fund Program , U.S. Department of Transportation, Washington, DC. . Obtained from http://www.pooledfund.org/. Site last accessed March 10, 2009.

6. Agent, K.R., Stamatiadas, N., and Jones, S. (1996). Development of Accident Reduction Factors, KTC-96-13, Kentucky Transportation Center, University of Kentucky, Lexington, KY.

7. van Driel, C.J.G., Davidse, R.J., and van Maarseveen, M.F.A.M. (2004). "The Effects of an Edgeline on Speed and Lateral Position: A Meta-Analysis," Accident Analysis and Prevention, 36(4), 671–682.

8. Molino, J., Katz, B., Duke, D., Opiela, K., Andersen, C., and Moyer, M. (2004). Field Validation for the Relative Effectiveness of Combinations of Pavement Markings and RRPMs in Recognizing Curves at Night, Transportation Research Board 2004 Annual Meeting CD-ROM, Transportation Research Board, Washington, DC.

9. Agent, K.R. and Creasey, T. (1986). Delineation of Horizontal Curves,Interim Report UKTRP-86-4, University of Kentucky, Lexington, KY.

10. Montella, A. (2009). Safety Evaluation of Curve Delineation Improvements: An Empirical Bayes Observational Before-After Study, Transportation Research Board 2009 Annual Meeting CD-ROM, Transportation Research Board, Washington, DC.

11. Ewing, R. (1999). Traffic Calming: State of the Practice, Institute of Transportation Engineers, Washington, DC.

12. Marek, J.C. and Walgren, S. (2000). Mid-Block Speed Control: Chicanes and Speed Humps, Seattle, WA . Obtained from: http://www.seattle.gov/transportation/docs/ITErevfin.pdf. Site last accessed October 23, 2009.

13. King, M.R. (1999). Calming New York City Intersections, Urban Street Symposium Conference Proceedings, Transportation Research Board, Washington, DC.

14. Huang, H.F. and Cynecki, M.J. (2000). "Effects of Traffic Calming Measures on Pedestrian and Motorist Behavior," Transportation Research Record 1705, Transportation Research Board, Washington, DC.

15. Williams, J.R., Chou, T.C., and Wallick, B.L. (2000). Advanced Rendering Cluster for Highway Experimental Research (ARCHER), Proceedings of 2005 Driving Simulation Conference North America, Orlando, FL.

16. Kennedy, R.S., Lane, N.E., Berbaum, K.S., and Lilienthal, M.G.(1993). "Simulator Sickness Questionnaire: An Enhanced Method for Quantifying Simulator Sickness," The International Journal of Aviation Psychology, 3(3), 203–220.

17. Cobb, S.V. and Nichols, S.C. (1998). "Static Posture Tests for the Assessment of Postural Instability After Virtual Environment Use," Brain Research Bulletin, 47(5), 459–464.

18. Federal Highway Administration. (2003). Manual of Uniform Traffic Control Devices (MUTCD), U.S. Department of Transportation, Washington , DC. .

19. Molino, J., Katz, B., Donnell, E., and Opiela, K. (2008). Using a Subjective Rating Scale in a Driving Simulator to Predict Real-World Stimulus-Response Relationships Concerning Nighttime Delineation for Curves, 87th Transportation Research Board Annual Meeting, Washington, DC.

20. Molino, J., Opiela, K., Andersen, C., and Moyer, M. (2003). "Relative Luminance of Retroreflective Raised Pavement Markers and Pavement Markings Stripes on Simulated Rural Two-Lane Roads," Transportation Research Record 1844, Transportation Research Board, Washington, DC.

21. Inman, V., Davis , G., El-Shawarby, I., and Rakha, H. (2006). Field and Driving Simulator Validations of System for Warning Potential Victims of Red-Light Violators,85th Transportation Research Board Annual Meeting, Washington, DC.

22. Turner, D., Nitzburg, M., and Knoblauch, R. (1998). "Ultraviolet Headlamp Technology for Nighttime Enhancement of Roadway Markings and Pedestrians," Transportation Research Record 1636, Transportation Research Board, Washington, DC.

Previous | Table of Contents

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