Use of Physical Devices for Calming Traffic along Major Roads through Small Rural Communities in Iowa

Abstract

Many rural communities have developed around highways or major county roads. As a result, the main street through small rural communities is often part of a high-speed rural highway. Highways and county roads are characterized by high speeds outside the city limits and then transition into a reduced-speed section through the rural community. Consequently, drivers passing through the community may enter at high speeds and then maintain those speeds throughout. Traffic calming in small rural communities along major roadways is common in Europe, but the United States does not have experience with applying traffic calming outside of major urban areas. Seven different low-cost traffic treatments were implemented and evaluated in five rural Iowa communities. Two of the treatments physically affected the roadway cross-section. A speed table was placed along the major road (County Highway E-23) in Gilbert, Iowa, and longitudinal channelizers were used to create a center island narrowing along County Highway R-38 in Slater, Iowa. Before and after speed studies were conducted. Speed studies were conducted at 1, 3, 9, and 12 months after installation of the treatments to evaluate their effectiveness over time. Both treatments successfully reduced mean speed, 85th percentile speed, and fraction of vehicles traveling 5, 10, 15, and 20 mph over the posted speed limit; reductions were sustained over time.

Effect of In-Vehicle Audio Warning System on Driver’s Speed Control Performance in Transition Zones from Rural Areas to Urban Areas

“…When drivers enter the transition zone, they tend to underestimate their speeds because of long periods of high speed driving, which is called speed adaptation [ 14 , 15 , 16 ]. Therefore, drivers are still in high-speed driving where traffic density, pedestrians, cyclists and virtual complexity increase, which leads to a higher crash rate in the transition zones [ 17 , 18 ]. The crash data in Victoria, Australia, in 1992 indicated that the fatality rate (45 fatalities per 100 million vehicle-miles per year) in transition zones was significantly higher than that (27 fatalities per 100 million vehicle-mile per year) in rural zones [ 19 ].…”

Geometry Optimization of Speed Humps Based on Ride Comfort and Driving-Safety-Based Assessment

“…In another study by Moreno et al, given the geometrical characteristics of flat-top humps, the speed profiles of vehicles passing through these humps were assessed ( 15 ). Hallmark et al assessed traffic calming tools on the main roads passing through small rural communities in Iowa ( 16 ). The speed of vehicles was measured by pneumatic tubes that were positioned upstream and downstream of the hump, to determine the effectiveness of each measure, and speed data were monitored after 1, 3, 9, and 12 months of installation.…”

Safety Effects of Turning Movement Restrictions at Stop-Controlled Intersections

“…The researchers concluded that the reduced slope of the regression line for raised median corridors demonstrates there are relatively lower crash rates in corridors with raised medians as a result of the reduced conflict points. A study with data from seven States by Hallmark et al suggested raised medians reduced crashes by at least 40 percent in urban settings ( 6 ).…”