Since 1991, Congress has recognised that improving roadway safety hardware can significantly reduce fatalities and injuries on the nation’s roadways and contribute to safer roads in America. In addition, as early as 1994, the FHWA called for the replacement of old and obsolete roadway safety features such as blunt and guardrail terminals.
A comprehensive approach to updating and improving roadway safety hardware can be an effective method to accomplishing the goal of towards zero death and safer roads in America.
There are a number of devices that are specifically designed to alleviate the severity of and/or prevent roadway departures. For example:
Shoulder-applied guardrail hardware safety features
Median barriers are longitudinal barriers most commonly used to separate opposing directions of traffic on a divided highway. While these systems may not reduce the frequency of crashes due to roadway departure, they can definitely help prevent a median crash from becoming a median crossover head-on collision.
Barrier design and placement needs to effectively protect motorists travelling in opposing lanes, while also considering the safety of the occupants of the offending vehicle. Among the factors involved in selection of a barrier system are the types of vehicles using the roadway, the roadway geometry, and the potential severity of a median crossover crash. Standard barriers capable of redirecting passenger cars, light vans and trucks are considered cost effective for most situations. However, at locations with adverse geometrics, high traffic volumes and speeds, significant amounts of heavy truck traffic, or special environmental considerations, a higher performance median barrier may be more appropriate.
There are three basic categories of midpoint barriers.
Rigid barrier system
Semi-rigid barrier system
Flexible barrier system
Rigid barriers: Concrete barriers are the most common type of rigid median barrier in use today contributing to safer roads in America. While the initial cost of installation can be relatively high, concrete barriers are known for their relatively low life-cycle cost, and effective safety performance.
Semi-rigid barriers: Commonly referred to as guardrail or guide rail, semi-rigid barriers typically consist of connected segments of metal railing supported by posts and blocks. The semi-rigid barrier system is most suitable for use in traversable medians having a little change in grade and cross-slope. In comparison to rigid barriers, semi-rigid barriers can be less costly, but can be more difficult to install in areas with slope and poor soil conditions.
Cable barriers: A typical cable barrier consists of multiple steel cables that are connected to a series of posts. These systems are considered the most versatile and forgiving barrier systems available for reducing the severity of median crossover crashes. Cable median barriers minimize the forces on the vehicle and its occupants and absorb most of the energy during a crash. Cable barrier systems have a lower installation cost.
While no barrier can eliminate the consequences for every driver who runs off the road, cable median barrier is expected to reduce the number of vehicles that cross a median and enter oncoming traffic.
Brightness and Visibility of Signage and Markings
Driving at night or in adverse weather increases the risk of roadway crashes. Crash data bear out the importance of safety improvements targeted toward nighttime driving. While only 25 percent of travel occurs at night, more than half of traffic fatalities occur during nighttime hours. Almost 60 percent of all highway fatalities involve vehicles running off the road. While nighttime crashes are attributable to a wide variety of causes such as impaired driving, drowsiness, speed, etc., pavement markings with adequately maintained retroreflectivity help drivers navigate more safely on unfamiliar roads and through unexpected hazards. In addition to properly maintaining roadway markings and traffic signs, it is important that the materials used to manufacture these products be environmentally friendly.
According to the Federal Highway Administration (FHWA) the rate of traffic fatalities is three times higher at night than during the day. One of the most important factors contributing to this tragic difference is night time drivers simply lack the visual cues they receive during daylight hours. A number of significant changes taking place on the nation’s roadways could make this situation even worse in the years ahead.
The percentages of person’s aged 65 and older who are licensed drivers has increased from 61 percent in 1980 to 72 percent in 1990 and 80 percent in 2003. By 2020, people in this age group will represent one of every five licensed drivers, and the proportion is expected to increase to one in four by 2030.
As a group, older drivers tend to be relatively safe drivers with a substantially lower rate of crashes per licensed driver compared to drivers aged 16-24. On the other hand, highway safety data indicate clearly that older drivers are at a significantly higher risk of being injured or killed when crashes do occur. Compared with an overall fatality rate of 2.00 per 1, 000 crashes, persons aged 65 – 74 have a fatality rate of 3.2. The rate climbs to 5.3 for those aged 75-84 and at 85 and above, the rate is 8.6.
Traffic congestion, particularly in urban areas, contributes to a degradation of air quality, jeopardises safety, impedes efforts to conserve energy, reduces productivity and results in delays that affect our standard of living and quality of life. Its adverse effects on our national economy are estimated to cost us over $75 billion annually.
TRIP, a non-profit organisation is backed by corporations involved in the engineering of freeways as well as obtaining financial assistance from insurance companies, the manufacturers of equipment, distributors and suppliers that provide information endorsing policies which lessen traffic jams and improve other conditions such as the state of roads and overpasses, and thereby contribute to the safety of road transportation, resulting in economic abundance and safer roads in America.