Bicycle Compatible Roadways

A Study of Bicycle Lanes versus Wide Curb Lanes

William W. Hunter

Highway Safety Research Center

University of North Carolina

Overview

This paper presents results from a 3-year study of bicycle lanes (BLs) versus wide curb lanes (WCLs) performed for the Federal Highway Administration (FHWA). In the parent study, bicyclists riding in either a BL or WCL were videotaped as they approached and proceeded through eight BL and eight WCL intersections with varying speed and traffic conditions in the cities of Austin, TX; Gainesville, FL; and Santa Barbara, CA. Approximately 4,600 bicyclists were videotaped (2,700 riding in BLs and 1,900 in WCLs). The videotapes were coded to learn about operational characteristics (e.g., intersection approach position and subsequent maneuvers) and conflicts with motor vehicles, other bicycles, or pedestrians. A conflict was defined as an interaction between a bicycle and motor vehicle, pedestrian, or other bicycle such that at least one of the parties had to change speed or direction to avoid the other. Both bicyclist and motorist maneuvers in conflict situations were coded and analyzed. This would cover maneuvers such as a bicyclist moving incorrectly from the bicycle lane into the traffic lane prior to making a left turn, or conversely, a motor vehicle passing a bicyclist and then abruptly turning right across its path.

Besides videotape data, bicyclist experience data were collected through use of an oral survey. In addition, bicycle crash data from each city were “typed” and analyzed.

Summary of Main Results

Bicyclist Characteristics

q        The overwhelming majority of videotaped bicyclists were between the ages of 16 and 64. Slightly more than three-fourths were male.

q        Overall, 5.6 percent of the bicyclists were riding the wrong way (i.e., facing traffic). This included 1.3 percent in the road and 4.3 percent on sidewalks. However, wrong-way riding was much more prevalent on the sidewalk at WCL sites (7.0 percent) compared to BL sites (2.3 percent). Eliminating sidewalk riding from the comparison, however, still resulted in significantly more wrong way riding associated with WCL sites (1.7 percent) than BL sites (1.0 percent).

q        A bicyclist experience oral survey was administered to bicyclists proceeding through the project sites on days when videotaping was not being done. There were no statistically significant differences in the age, gender, and helmet use of bicyclists by type of facility. Higher proportions of Whites and Blacks rode in WCL situations and higher proportions of Asians and Hispanics in BL situations, and the differences were significant.

q        Bicyclists surveyed at WCL sites tended to ride more days per week, but the miles per week for bicyclists at BL versus WCL sites were equivalent. Overall about one-third of the riders at both BL and WCL sites considered themselves to be experienced bicyclists.

q        When bicyclists were surveyed, their riding location (i.e., in the street or on the sidewalk) when approaching the survey station was recorded. Surveyed bicyclists showed the same tendency as the videotaped bicyclists in that sidewalk riding was more associated with WCL sites.

 

Midblock Movements

q        In the midblock or intersection approach area (between 90 and 150 m from the intersection), significantly more motor vehicles passing bicycles on the left encroached into the adjacent traffic lane from WCL situations (17 percent) compared to BL situations (7 percent). This is in agreement with results from a recent Florida DOT study (Harkey and Stewart, 1997). However, encroachments into the adjacent traffic lane very rarely resulted in a conflict with another motor vehicle.

 

Intersection Movements

·         The intersection was defined as starting 90 m upstream from the stop bar and included the intersection proper. Proportionally more bicyclists approached the intersection on a sidewalk when the facility was a WCL (15 percent) than a BL (3 percent).

·         Overall 92 percent of bicyclists obeyed the traffic signals that were present, and there were no differences by facility type. When a signal was disobeyed, 16 percent of the actions were considered somewhat unsafe and 2 percent definitely unsafe. There were no differences by facility type.

·         Overall 75 percent of bicyclists obeyed existing stop signs. Proportionally more bicyclists obeyed stop signs at BL sites (81 percent) than at WCL sites (55 percent).  When a stop sign was disobeyed, 13 percent were considered somewhat unsafe and 2 percent definitely unsafe. The proportion of bicyclists with both somewhat unsafe (19 versus 5 percent) and definitely unsafe (3 versus 0 percent) movements was higher at BL sites. The differences between BL and WCL sites were significant when the somewhat unsafe and definitely unsafe categories were combined.

·         Seventy-two percent of the bicyclists went straight through the intersection, with another 15 percent turning left and 13 percent turning right. There were no differences by facility type. Nine percent of the bicyclists tended to shy to the right (i.e., move to the right and away from traffic) as they went straight through the intersection (11 percent in BLs and 7 percent in WCLs), and this difference was significant.

     

·         Left turns presented a problem for bicyclists and were made in a variety of ways (figure 1). Overall 44 percent made left turns like a motor vehicle with proper lane destination positioning (41 percent from BL sites and 48 percent from WCL sites). On the other hand, 14 percent of bicyclists at WCL sites made motor vehicle style left turns with improper lane destination positioning compared to 3 percent from BL sites. There were proportionally more pedestrian style left turns from WCL sites (24 percent versus 12 percent from BL sites). Both findings may reflect the generally higher traffic volumes and speeds and greater number of lanes at WCL sites.

·         Right turns for bicyclists were an easier maneuver, with only 13 percent made in a non-standard fashion (e.g., from a BL or WCL to a wrong way position on the cross street). Nineteen percent of the right turns made at WCL sites were non-standard versus 10 percent of right turns at BL sites, and the differences were significant.

 

Midblock Conflicts

·         Of the 188 midblock conflicts 71 percent were bicycle/motor vehicle, 10 percent bicycle/bicycle, and 19 percent bicycle/pedestrian. Almost all of the bike/bike conflicts occurred in BLs. Compared to BLs, bicyclists in WCLs experienced more bike/pedestrian conflicts (30 percent versus 16 percent, and reflective of the increased sidewalk riding in WCL situations) and less bike/bike conflicts. The differences by facility type were statistically significant.

·         There were no differences in the bicycle or motor vehicle avoidance response scales by facility type. The scales ranged from no change in riding or driving up to collision or near crash.

·         Overall 98 percent of the midblock conflicts were coded as minor, and there were no differences by facility type.

 

·         Bicycle actions more associated with BLs in these midblock conflicts included the bicycle having to slow, stop, or swerve for traffic not influenced by the intersection; the bicycle turning or swerving across a lane of traffic (figure 2); encounters with other bikes; and “other” bike actions (such as an improper left turn). The bicycle action more associated with WCLs in these midblock conflicts was encounters with pedestrians.

·         Motor vehicle actions more associated with BLs in these midblock conflicts included illegal parking in the BL and entering/exiting on-street parking or a driver or passenger entering/exiting a parked or stopped vehicle. Motor vehicle actions more associated with WCL conflicts included turning right in front of a bicyclist after overtaking and “other” actions such as failing to yield, improper right turns, and crowding bikes.

 

Intersection Conflicts

·         Of the 198 intersection conflicts 79 percent were bike/motor vehicle, 10 percent bike/bike, and 10 percent bike/pedestrian. The differences in the BL/WCL distributions were statistically significant. There were proportionally more bike/bike conflicts in BLs (15 percent) and less in WCLs (4 percent). Conversely, there were proportionally more bike/pedestrian conflicts in WCLs (17 percent, and again reflective of sidewalk riding) and less in BLs (6 percent).

·         The position of the motor vehicle with respect to the bicycle in the intersection conflicts was 66 percent in the same direction, 6 percent in the opposing direction, 5 percent approaching from the left, 15 percent approaching from the right, and 7 percent approaching from some other position. There were no differences by facility type.

·         here were no differences in the bicycle or motor vehicle avoidance response scales by facility type.

·         Overall 93 percent of the intersection conflicts were coded as minor, and there were no differences by facility type.

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·         Bicycle actions more associated with BLs in these intersection conflicts included the bicycle having to slow/stop/swerve for intersection traffic, the bicycle having to slow/stop/swerve for traffic not influenced by the intersection, and the bicycle turning or swerving across a lane of traffic. Bicycle actions more associated with WCLs included passing slow moving or stopped vehicles on the right, encounters with pedestrians, and “other” actions such as improper left turns and merging onto the road from a sidewalk.

·         Motor vehicle actions more associated with BLs included illegal parking in the BL and “other” actions such as a driver or passenger entering/exiting a parked or stopped vehicle (figure 3) and crowding the BL. Motor vehicle actions more associated with WCLs included having to slow/stop/swerve for intersection traffic and turning right in front of a bicyclist after overtaking.

 

Comparisons with Crash Data

·         One year (1995) of police-reported crash data was “typed” using the NHTSA methodology for all three of the project communities. There were parallels to the videotape data.

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·         In Santa Barbara, one of the two most frequently occurring crash types was the bicyclist striking a parked vehicle. Santa Barbara had a number of individual intersections where parking was part of the bike facility (figure 4), and overall 41 percent of the bicyclists were recorded as riding next to parked vehicles, as compared to 21 percent of the Austin bicyclists and none of the Gainesville bicyclists.

·         In Gainesville, the most frequently occurring crash type was motorist drive out at stop sign. In three out of four of these crashes, the bicyclist was riding the wrong way (facing traffic) on the sidewalk. Seventeen percent of the Gainesville bicyclists were observed approaching the targeted intersections on the sidewalk, as compared to less than three percent of the Austin bicyclists and less than two percent of the Santa Barbara bicyclists. In addition, nine percent of the Gainesville bicyclists were observed riding the wrong direction on a sidewalk, compared to one percent of both the Austin and Santa Barbara bicyclists. Wrong way sidewalk riding was also a factor in 87 percent of Gainesville’s Right Turn on Red crashes, and 75 percent of their Drive Out at Midblock crashes.

·         In Austin, 11 percent of the bicyclists made “advance crossovers” to the left prior to the intersection (figure 13), as compared to 3 percent in both Gainesville and Santa Barbara. Nearly six percent of the crashes reported for Austin were Bicyclist Left Turn in Front of Motorist. None of these types of crashes were reported for Gainesville or Santa Barbara.

 

Conclusions

The debate over whether BLs or WCLs are preferable has been heated for many years and is not unlike the seat belts versus air bags dichotomy that prevented a concerted approach to the promotion of occupant restraints in the U.S. While both BLs and WCLs are acceptable facilities in many locations, the debate has sometimes forced decision makers to choose which facility type they prefer, to the exclusion of the other.

Across the board these facilities work well, with the vast majority of identified conflicts in this study being minor in nature. Both behavioral actions and geometric characteristics were identified as problems in the study of these bicycle facilities, and there are remedies for these. However, in most cases the noted problems at the higher conflict rate sites could not be labeled as particular BL or WCL deficiencies. The destination patterns of bicyclists traveling through the project sites led to maneuvers and conflicts that in many cases would have occurred whether the bicycle facility present was either a BL or WCL.

This project did not specifically compare BLs and WCLs with standard traffic lanes, but since space is such a desired attribute for comfort when bicycling, it is felt that both BL and WCL facilities can and should be used to improve riding conditions for bicyclists. Given the heated debate in the past, this should be viewed as a positive finding for the bicycling community.

 

References

Harkey, D.L. and Stewart, J.R.  “Evaluation of Shared-Use Facilities for Bicycles and Motor Vehicles,” Transportation Research Record 1578, 1997, pp. 111-118.

Hunter, W.W., Stewart, J.R., Stutts, J.C., Huang, H.H., and Pein, W.E.  A Comparative Analysis of Bicycle Lanes Versus Wide Curb Lanes, Final Report, Publication No. FHWA-RD-98-xxx, Federal Highway Administration, McLean, Virginia, (In Press).

Hunter, W.W., Stutts, J.C., Pein, W.E., and Cox, C.L.  Pedestrian and Bicycle Crash Types of the Early 1990’s, Publication No. FHWA-RD-95-163, Federal Highway Administration, McLean, Virginia, 1996.

National Bicycling and Walking Study, Publication No. FHWA-PD-94-023, Federal Highway Administration, Washington, DC, 1994.

 

Bio:

Bill Hunter has worked on a variety of projects in the highway safety field for 25 years. Many of his recent projects have involved studies of bicycle-pedestrian activity.  These include ped/bike crash typing study for the Centers for Disease Control, a three year study of bike lanes versus wide curb lanes for the Federal Highway Administration (FHWA), and an ongoing study of the innovative on-street bicycle countermeasures for FHWA.  He was a contributing author of the National Bicycling and Walking Study for the US DOT.