#14 – Red Shoulders as a Bicycle Facility

Lake County, Florida

William W. Hunter, Senior Research Scientist, UNC Highway Safety Research Center

Background

A scenic road in Lake County, Florida, is the subject of this evaluation. Lakeshore Drive is about 8 km (5mi) in length and lies between Mount Dora and Tavares, a pair of communities located about 56 km (35 mi) northwest of Orlando. The road is under both city and county jurisdiction, although maintenance is performed by the county. The location is popular with bicyclists and walkers. Lake County has some hilly terrain and is frequented by bicyclists riding for physical fitness or preparing for races. Bicycling groups from the Orlando area often ride on Lakeshore Drive as part of longer bike rides. The route is also used extensively during the Mount Dora Bicycle Festival each fall.

In the early 1990s, the road was slated to receive shoulders. Residents who feared that speeds would increase with the addition of shoulders opposed the project. The Florida Department of Transportation (FDOT) suggested that painting the shoulders might be a treatment that could be adapted from Europe. Even though the travel lanes would remain at approximately 2.9 m (9.5 ft), adding shoulders would physically widen the cross-section. The painting of the shoulders was intended to make the road appear no wider than before.

Countermeasures

In the summer of 1996, a 1.8 km (1.1 mi) section of the road was widened with 0.9 m (3 ft) shoulders. The shoulders were colored red with a paint that is used on tennis courts (figure 1).

Figure 1. View of the red shoulders.

The 1.8 m (1.1 mi) treated section of road has a 56 km/h (35 mph) speed limit and is primarily a two-lane rural roadway with about 1,700 vehicles per day. There are two main intersections along the section where the shoulders have been painted red. In one area a railroad divides the road into two one-lane sections. At the end of this section a roundabout has been added, with the railroad extending through the roundabout and the colored shoulders ending at the entry to the roundabout. Several more intersections (stop-sign-controlled) intersect Lakeshore Drive along the red shoulder section.

Evaluation and Results

The evaluation examined several items. The treatment produced a non-slippery surface that maintained its appearance rather well for some time after the initial painting. The most obvious discolorations occurred at locations with frequent motor vehicle traffic, such as mail trucks stopping at mail boxes.

The Lake County Department of Public Services collected speed data before and after the addition of the red shoulders to determine if motor vehicle speeds had changed. Videotape was taken of bicyclists traveling along the roadway at sections with and without red shoulders. Besides determining whether the shoulder was used by bicyclists, the lateral positioning of bicyclists being passed by motor vehicles was determined, along with the amount and severity of vehicular encroachment into the opposing lane of travel. If encroachment occurred, conflicts between the passing and oncoming motor vehicles were recorded. In addition, any conflicts between motor vehicles and bicycles were recorded. Also, the Lake County Department of Public Works developed a questionnaire that was administered to bicyclists riding along Lakeshore Drive to obtain feedback concerning the red shoulders.

Evaluation of the red shoulders considered a variety of issues. Major findings are highlighted below:

Full-time bicyclist use of the shoulder tended to be around 80 percent, and another six percent used the shoulder partially.
The frequency of motor vehicles encroaching over the center line when passing a bicyclist was greater at the site without red shoulders.
The severity of encroachment was fairly evenly split between minor, moderate, and severe at the red shoulder site. Almost 93 percent of the encroachments were severe at the site without red shoulders.
There were no motor vehicle-to-motor vehicle conflicts when passing a bicyclist at the red shoulder site, and there were eight (four minor and four serious) at the site without red shoulders.
Bicyclists positioned themselves about the same distance (about 0.5 m (1.5 ft)) from the edge of pavement on both the red shoulder and non-red shoulder sites.
The spacing between bicycles and passing motor vehicles was statistically significantly greater (about 0.1 m (0.6 ft)) at the site without red shoulders.
Mean and 85th percentile speeds showed little difference before and after the placement of the red shoulder.
Survey responses showed that 80 percent of the respondents thought the red shoulders resulted in no change in the speed of cars and trucks. More than 85 percent responded that there was more space between bicycles and passing motor vehicles with the red shoulders in place, even though actual measurements of spacing distance showed greater clearance between bicycles and motor vehicles on the section of roadway without red shoulders. A final survey response showed that almost 80 percent thought the red shoulders made them feel safer than ordinary unpainted shoulders. Thus, bicyclist comfort level was increased by installing the red shoulders.

Conclusions and Recommendations

The red shoulder section of roadway not only has been well received but also has functioned well in an operational sense. The comfort level of bicyclists appears to be greater on the red shoulder section, which matches the results of a recent Federal Highway Administration study focused on the development of a bicycle compatibility index (BCI), a means of measuring the “bicycle friendliness” of a roadway (Harkey, Reinfurt, Knuiman, Stewart, and Sorton, 1998). In this study the variable with the largest effect on the index was the presence of a bicycle lane or paved shoulder. In other words, the presence of a bicycle lane or paved shoulder increased the comfort level more than any other factors.

Use of the shoulder was quite high. Riders who did not use the red shoulder tended to be part of a group, where the typical placement was to have one or more following cyclists riding to the left of lead cyclists for safety purposes. In addition, cyclists in pairs often rode abreast so they could converse. Children also had a tendency to be partial users of the red shoulders, with a tendency to cross back and forth across the road.

Perhaps the most important evaluation parameter was the speed of motor vehicle traffic before and after the placement of the red shoulders. The primary intent of the red shoulders was to create a visual sense of no widening of the road, which would lead to no increase in traffic speed. This appears to be the case. One could speculate that the general curvy alignment of the roadway could also have a bearing on this result; however, the section of the roadway where the red shoulder was installed is relatively straight.

Costs and Funding

The cost of painting the 1.8 m (1.1 mi) section of red shoulders (in both travel directions) was approximately $6,600. The widening and resurfacing costs amounted to $173,000.

References

Harkey, D.L., Reinfurt, D.W., Knuiman, M., Stewart, J.R., and Sorton, A., Development of the Bicycle Compatibility Index: A Level of Service Concept, Report No. FHWA-RD-98-072, Federal Highway Administration, Washington, DC, December 1998.
Hunter, W.W., Stewart, J.R., Stutts, J.C., Huang, H.F., and Pein, W.E., A Comparative Analysis of Bicycle Lanes versus Wide Curb Lanes: Final Report, Publication No. FHWA-RD-99-034, Federal Highway Administration, Washington, DC, October 1999.

Contact

William W. Hunter
UNC Highway Safety Research Center
730 Martin Luther King Jr. Blvd, Suite 300
Chapel Hill, NC 27599-3430
(919) 962-8716
bill_hunter@unc.edu

The modification (red shoulders) that is the subject of this case study is not compliant with the Manual on Uniform Traffic Control Devices, nor is it currently being considered for inclusion. Accordingly, it is imperative that any jurisdiction wishing to utilize red shoulders (or any other non-approved traffic control device) should seek experimental approval from the Federal Highway Administration. For information on how to do so, please visit this Web site: http://mutcd.fhwa.dot.gov/kno-amend.htm.