Paving the Way to Progress
By Kevin Clemens
Much of what we've covered so far can be considered "active" safety – road designs that help you avoid an accident in the first place. But, of course, accidents do happen, and here, too, highway engineers have advanced the state of the art considerably since Eisenhower's day.
Concrete barriers alongside many highways are designed to direct a vehicle's path, preventing an out-of-control vehicle from crossing into the opposing lanes, or put another way, helping to maintain the original direction of travel. On the other hand, plastic, water-filled hydro-barriers are placed in front of bridge abutments and other immovable objects. These barriers are engineered to perform in much the same way as the crumple zones in your vehicle – to absorb impact energy if a vehicle strikes it.
Even the way in which road signs are positioned and held in place has been closely examined in modern highway design. In the past, road signs and traffic lights were mounted on strong telephone poles or stout steel posts. While they would last a long time, these rigid signs presented a grave risk of injury risk should a vehicle hit them. Today, many supporting poles and sign posts are designed to break away when they are struck by a vehicle. In this way, these sign posts are much less likely to intrude into the passenger compartment during a collision, helping to protect the occupants.
Together, these new types of poles and barrier systems have saved countless lives and injuries as they redirect and absorb collision energy or simply break away.
A Sign of the Times
Another dramatic improvement is the information imparted to drivers from highway signs. The technology of today's road signs includes highly reflective sign materials, internationally standardized symbols and illuminated signs that are visible in bad weather or low light conditions. Some of the latest thinking includes variable-message signs that can supply different information to drivers depending upon weather, time of day or traffic conditions.
Of course, road signs aren't the only information system found on America's roads. Advances have been made in the materials and application of the lines painted onto the road which help control and direct traffic flow. Keep in mind that road markings and reflectors must be durable enough to withstand being run over by millions of vehicles and tough enough to stand up to the scraping of snowplows, road salt and submersion on flooded highways. New epoxy-based paints, hot-applied thermoplastic tapes and polyester resins are finding their way onto more and more highways. The scuff- and dirt-resistance of these high-tech materials is especially clear at night when drivers can easily distinguish between lanes, and see the edges of the roadway more clearly.
Many more highways are also equipped with centerline reflectors that clearly delineate the lanes of travel. Called "Botts Dots," they are the brainchild of Elbert D. Botts who, in the 1950s, invented a reflective raised "dot" and found a way to adhere it to the surface of the road. These raised "dots" provide a bump-bump-bump reminder if your vehicle crosses the center line, and allow added visibility to see lane stripes at night, especially in rain or fog.
The Road to the Future
The road to increased highway safety never ends. As traffic levels continue to increase, engineers and researchers are finding new and innovative ways to keep it all flowing smoothly and safely.
The use of new paving materials that provide better wet-weather and winter grip is now under study. Traffic lights and variable speed limit signs that sense traffic flow patterns are becoming "smarter" by anticipating actions that will move traffic more smoothly. Experiments are taking place with in-car transmitters and receivers that communicate with the highway to provide the driver with more information than a road sign ever could. Some engineers are even predicting that the future will see cars that drive themselves to their destinations, once the driver has slotted onto a new kind of super-intelligent highway system. If it all sounds a bit "Buck Rogers" and maybe even a little unnerving to those of us who like to drive, such drastic concepts may become a necessity in the not-too-distant future, as more and more cars and trucks hit the highways.
Kevin Clemens has both undergraduate and graduate degrees in engineering and has authored several patents. A former Product Public Relations Director for Michelin Tires and Technical Editor at "Automobile Magazine," Kevin writes for "European Car" and other publications when not competing in rallies in various parts of the world with his vintage automobiles.