Traffic crashes are the largest source of fatality from traumatic injury in rural America. The high risk of accidents in these areas is a concern for all travelers, not just rural residents. Based on statistics from the Federal Highway Administration (FHWA), 60% of crash fatalities occur on rural highways, while only 39% of the vehicle-miles traveled occur on these roads.
“When we analyzed these numbers further, we found that a driver is four times more likely to be killed on a noninterstate road than on an interstate freeway,” said Stephen Albert, director of the Western Transportation Institute (WTI) at Montana State University.
Moreover, travel in rural areas is expected to increase. For example, research by the Western Governors’ Association estimates that 42 million more people and cars will be added to the western transportation system by 2030. Recent migration and land-use studies indicate an increase in rural and frontier populations based on the “ex-urban flight,” described as urban residents who are bypassing moves to traditional suburban areas in favor of rural destinations that offer greater quality of life. As travel continues to grow on secondary highways, it is inevitable that accidents will increase as well unless safety initiatives are directed to these roadways.
The real rural
Traditionally, national transportation initiatives have focused on congestion issues in urban areas. This is beginning to change as the U.S. DOT introduces efforts such as the Rural Safety Innovation Program to increase deployment of advanced technologies on rural corridors. While new technologies hold tremendous promise, new deployments must first address the real-world challenges of rural travel, roadway facilities and the causes of rural fatal crashes:
- Do the local transportation agencies have the resources to install, monitor and maintain the deployment?;
- Does the technological backbone exist (i.e., infrastructure, communications) to support installation in a remote location?;
- Is the average annual daily traffic (AADT) count sufficient to evaluate the effectiveness of the countermeasure?; and
- What are the unique risk factors and sociocultural influences for rural fatal crashes?
“Rural roadway design, rural geography and other factors, including driver behavior and psychosocial influences, dictate unique solutions to rural safety problems,” said Dr. Nic Ward, who manages the Human Factors Research Program at WTI. “You can’t just take an urban solution and put a rural hat on it.”
One technological tool that is helping investigate rural risk factors in order to select, develop and test safety countermeasures is simulation. The new generation of driving simulators combines the cabs of actual vehicles with computer-generated driving scenarios that realistically replicate actual roadway segments and driving conditions. Using simulators in the preliminary stages of developing collision mitigation measures has many advantages for rural transportation agencies:
- Safety—The simulator is a controlled environment that does not expose test subjects to actual driving hazards;
- Cost—Agencies can design and test measures in the relative low cost of a virtual environment;
- Risk management—By conducting preliminary evaluation and troubleshooting in the simulator, agencies are less likely to invest in or install infrastructure that must be removed or modified later; and
- Traffic disruption—Testing a countermeasure in a simulated location causes no disruption to traffic at the actual site. Rural corridors often consist of two-lane roads with few alternative routes.
Two ways in which research institutes and rural agencies are using simulators to develop safety countermeasures are identifying factors that increase crash risk and testing countermeasures prior to field deployment.
Cell disservice
Many human factors can significantly increase the risk of collisions. Identifying specific risky behaviors for a particular location (driver distraction, speeding, inattention to wildlife crossings, etc.) can play a critical role in designing effective countermeasures.
For example, a significant body of research has indicated that the use of cellular phones in moving vehicles can create a dangerous distraction to drivers in urban areas, but what about drivers using cell phones on less-congested rural roads?
WTI designed a simulator study in which the test subjects “drove” through a series of scenarios on rural roads. The study was sponsored in part by the Research and Innovative Technologies Administration of the U.S. DOT. As they drove, they used cell phones to dial and obtain information from a 5-1-1 traveler information system. The research was evaluating the driver distraction and not the functionality of the 5-1-1 system. Results indicated that drivers were less aware of their surroundings when interacting with the 5-1-1 traveler information system while using a cell phone and driving. Moreover, driving tasks that require more prompt response time—such as avoiding collisions during unexpected conflicts—were degraded by use of the cell phone, regardless of whether it was a handheld or hands-free device.
Another collision risk in rural environments is wildlife crossing the roadways. At Bozeman Pass on I-90, the Montana Department of Transportation (MDOT) and other parties are developing mitigation measures to reduce the number of collisions between vehicles and large animals. As part of the preliminary research, WTI created a driving scenario for the simulator that replicated the Bozeman Pass and used it to test driver response to various types of wildlife advisory message signs. The data collected helped identify which signs appear to have the biggest impact on driver behavior and may prove instrumental in the development of effective countermeasures for that location.
Now showing: U.S. 191
Simulator evaluation provides a valuable intermediate testing stage between planning and field deployment, where transportation agencies can see how well safety improvements may work before they start buying equipment or breaking ground. For rural agencies with limited resources, simulation can be a cost-effective option, especially in locations where construction can be challenging.
Researchers in the WTI driving simulation laboratory, in partnership with MDOT, created a simulation of approximately 22 miles of U.S. 191, between the town of Big Sky and the mouth of the canyon. Custom roadway tiles for the simulation were designed and programmed from MDOT’s as-built plans for the highway, topographic maps and video taken from a vehicle driving the route. The simulations serve as a tool to help develop and refine safety countermeasures.
For example, the deployment of dynamic message signs can be electronically simulated on a specific segment of the highway. Engineers can “drive the roadway” to examine the location or visibility of a message on the warning system. Or a sample of drivers can drive the scenarios to test how effective the signs are.
If testing suggests changes in the system, the simulation can be easily altered to represent the new specifications and refinements. In fact, the primary benefit of the visualization approach is that it allows engineers to refine the design at an early stage in the system development process before significant resources are invested in the deployment.
“Changes at this point may involve only a click-and-drag operation on a computer interface or rewriting a few lines of code,” said project principal investigator Mike Kelly. “Considerable time and money can be saved if changes need to be made to achieve the desired traffic objectives.”
More to see
With efforts such as these demonstrating promising benefits of simulation, rural agencies and research institutes are already looking ahead to expansions and enhancements of visualization tools. New technologies coming online will improve simulator capabilities, with features such as high-fidelity sound and motion cabs that replicate movements such as roll, surge and sway. These advancements will more realistically simulate the driving experience for the test subjects, enhancing the effectiveness of the simulator as an evaluation method.
Another approach is to supplement driving simulator testing with test-track evaluations. Test tracks represent another method to evaluate safety initiatives in a realistic scenario prior to field deployment and may serve as a logical next step to further validate simulator research. Transportation agencies can test the effectiveness of safety countermeasures by observing drivers in actual vehicles drive on a (closed) road segment, while still controlling the environment and protecting the safety of test participants. WTI, in partnership with federal, state and local officials, is developing a rural transportation research facility at a converted airport in Montana, which includes a test track. The track will help test the effectiveness of safety programs ranging from roadside animal detection devices to defensive driving courses for novice drivers.
Current and future driving simulation tools can help transportation agencies move toward solutions that are tailored to the unique challenges of driving on rural roads.
“Simulation can help us produce viable systems that make a real difference in reducing collisions, and ultimately the traffic fatality rate, on America’s highways,” said Ward.
RSS: Roads & Bridges Articles
