Urban Traffic on Rural Roads

by Steven G. Goodridge

bicycle chain

Peace and quiet, fresh air, green pastures and charming farms are some of the things that make cycling in rural areas around the Triangle so enjoyable. But paradise draws homebuyers, too, and sprawl is making quite a dent in our countryside. These days cyclists traveling outside the city limits are seeing fewer tractors and a lot more passenger trucks driven by cell-phone-toting commuters. Unfortunately, the future is likely to bring more bulldozers and more traffic to our favorite routes.

The placement of medium and high density urban development in previously rural areas around the Triangle - often remote to other urban development - has raised concerns among rural residents and members of Triangle city councils and planning boards. These "greenfield" urban developments are sometimes sited in rural areas because the land is cheap and there are fewer neighbors to generate political opposition compared to urban "infill" projects. Although land use decisions of this type have many important implications to consider, a primary concern for cyclists is transportation planning. Rural areas typically feature a sparse network of narrow roads designed for low traffic volumes. Urban development projects bring urban traffic volumes to these roads. In Green Level near Lake Jordan, development such as Cary Glen, Amberly, and the proposed White Oak Village will add tens of thousands of daily motor vehicle trips to area roads. This has a profound impact on traffic safety and comfort for cyclists.

Local leaders, urban planners and traffic engineers are aware of the growing traffic volumes and are working to mitigate the problem. However, their primary concern is typically the effects these volumes have on the convenience of motor travel, not the interests of cyclists. For instance, the town of Caryís new Adequate Public Facilities (APF) ordinance for roads does not allow major new development to occur where it will reduce the level of service (LOS) of nearby roads to below a grade D. The LOS rating of a road is determined primarily by motorist delays at intersections. A road can be very narrow and falling apart, but as long as traffic does not stack up unacceptably at intersections, the passing LOS grade will allow development to continue.

In much of rural Wake county and surrounding areas, rural intersections are not yet at failing level of service. In defense of the controversial White Oak Village development proposed for Green Level, Jerry Turner of Jerry Turner and Associates recently remarked that roadways in Green level are under capacity and would therefore support traffic generated by his clientís project. But the intersection-delay level of service metric fails to address many other problems that occur when urban traffic volumes are found on substandard rural roads. One problem is limited sight distance on winding routes, especially at driveways and intersections. The probability of crashes caused by motorists overdriving their sight distance might be tolerable at very low traffic volumes, but becomes a serious problem at high volumes. Another problem is accelerated degradation of the roadway surface. Two-lane rural roads are often built without a sufficiently strong base or any paved shoulder, which causes the asphalt to break down quickly under urban traffic - especially at the right edge of the narrow pavement. But of greatest concern to cyclists is the increased conflicts that occur when traffic volumes rise on narrow rural routes.

The recently developed Cary Comprehensive Transportation Plan clearly identifies the publicís desire to facilitate - or at least, avoid the discouragement of - alternative transportation modes such as walking and cycling. High traffic volumes on narrow, substandard rural roads discourage non-motorized transportation by increasing traffic conflicts. This is a simple matter of geometry. For instance, a cyclist requires at least three feet of pavement to reliably maintain control and avoid small surface hazards such as rocks and litter. Minimum legal passing distance is two feet, and many of the popular passenger trucks are nearly seven feet wide. By adding up these widths we see that at least twelve feet of space is required for motorists to pass cyclists properly. AASHTO, NCDOT, and the Cary Transportation Plan recommend fourteen-foot outside lanes on high-volume roads to facilitate safe passing of cyclists within a single lane.

Many rural two-lane roads in North Carolina feature only twenty feet of asphalt, with ten feet per lane and a steep slope into a drainage ditch on each side. Motorists must use part of the opposite lane in order to pass cyclists safely. With very low traffic volumes this is rarely a problem, which is why truly rural roads are among the most pleasant places for cycling. However, as traffic volumes increase, a continuous stream of oncoming vehicles makes it difficult for the motorist to find an opportunity to pass. This frustration often encourages motorists to pass at unsafe distances and/or harass cyclists for being on the road.

Compounding the problem for cyclists are surface hazards caused by the breakdown of pavement on the right edge of the roadway as previously described. Potholes and broken asphalt can cause cyclists to swerve, lose control, or even fall. Cyclists who hug the right edge of the asphalt under such conditions put themselves at considerable risk while encouraging motorists to pass at unsafe distance. Skilled cyclists often avoid the problem of sharing narrow lanes (especially where riding on the right edge may be hazardous) by "taking the lane," i.e. riding straight down the lane near its center, or just to the right of its center. This forces motorists to commit to using at least part of the adjacent lane when passing, and improves safety for the cyclist while potentially inconveniencing the motorist, who must wait for a safe opportunity to pass or travel at reduced speed. (Taking the lane is legal when required for safety, because operating as far right as is "practicable" implies operating no farther right than is safe.) Courteous cyclists who find they must take the lane try to minimize this inconvenience by pulling off the roadway every so often when traffic backs up. Unfortunately, the inconvenience of inadequate lane width frequently generates ill will between motorists and cyclists who often disagree about the proper way to share roads. This discourages cycling and encourages automobile dependency.

Conditions on inadequate roads are even worse for pedestrians. Pedestrians walking on rural roads without sidewalks are required by state law to walk facing traffic and yield to all vehicular traffic, including cyclists. With low traffic volumes, the pedestrian may occasionally have to step off the paved surface to let traffic pass. But at high vehicle volumes, the pedestrian must spend more time off the road than on the asphalt. Since drainage ditches and soft shoulders are unsuitable for safe, comfortable walking, pedestrian travel is discouraged and endangered by urban traffic on rural roads.

Urban growth is inevitable, and many of the dense "new-urbanist" or "neo-traditional" developments can reduce the total amount of land consumed by new residents. But civilization requires civilized roads. The costs of upgrading rural roads to preserve the travel rights of non-motorized users are significant. Despite aggressive road improvement programs, municipalities like Cary will never be able to catch up with the growing number of inadequate roads if people continue to make land use decisions that place urban traffic generators in rural areas separated by substandard links.

One of the basic principles of the "smart growth" ethos is to place new urban land uses in locations contiguous with existing urban development, such that less road mileage must be upgraded. Dense urban land uses work best when they are accompanied by increased density of through-roads and high connectivity to neighboring sites with compatible street networks. Given proper street design, i.e. wide curb lanes, such urban developments can be safe and pleasant for recreational cycling, and very convenient for utilitarian cycling. By comparison, locating dense urban development in rural locations concentrates traffic on substandard roads, since these residents typically commute to other urban destinations. City planners, engineers, and elected officials reviewing new development around the Triangle should pay closer attention to the hazards of urban traffic on rural roads as our metropolitan borders grow. As cyclists, it is in our interest to encourage them to do so.


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