"Why aren't the road lines painted in reflective paint or reflectors imbedded in the roads? I thought it was my age creeping up on me, but when my 16-year-old daughter returned home one rainy night and complained that she couldn't see the lines to keep in the lane of traffic, I knew it was a problem for young eyes, too!" she said.
An informal poll of family and friends indicates that many people share Murrell's peeve with road markings. I suspected that William F. Malone Jr., Traffic Division chief of the Howard County Department of Public Works, might be able to provide some information about the topic, and boy, was I right! "Lane marking material is a much larger subject than you realize," Malone wrote in a letter responding to my questions. "It is a science that is constantly being upgraded by the industry."
According to Malone, "reflectivity" in roadway marking is immaterial except in parking lots. Roads require "retro-reflectivity," meaning that the road markings reflect light back in the direction it came from, so light from car headlights are reflected back toward the driver.
Markings are generally not retro-reflective, so glass or ceramic beads are embedded in the markings - glass beads of varying sizes in paint and ceramic beads in pre-formed markings. If the road markings are to be painted on, the paint is applied and glass beads are dropped into the wet paint immediately afterward. "Look closely at new markings and you can see and feel the glass beads," Malone said.
However, how long the road markings last depends on several factors, including the amount and type of traffic and how many times the road is plowed. "We generally freshen our water-based, long-line paint markings once a year. We can sometimes get a couple years out of our transverse markings (crosswalks, stop bars) if the paint is put on thick and the winters are mild," Malone said. But this winter certainly can't be classified as mild, and the road markings are showing it.
From the information Malone provided, it seems that the road markings work their best on dry summer evenings. "When it rains, markings can be hard to see at night if the glass beads are under water," Malone said. "[It] depends on the cross slope and grade of the roadway, the intensity of rain and the profile of the glass beads."
But what about pre-formed markings? "Pre-formed markings in lieu of paint markings work very well at many locations," Malone said, primarily because they are thicker than paint and generally use ceramic beads. With the extra thickness, they are harder for rain to cover, making it easier for drivers to see the road markings on rainy nights.
Unfortunately, pre-formed markings are expensive and labor-intensive to install, although, Malone said, "to my mind, are well worth it on our larger roads."
"We used inlay tape on the southern portion of Snowden River Parkway that we overlaid last year," Malone said. "I would also like to use it on Broken Land Parkway when it is overlaid."
Pre-formed long lines are best installed when a road is being repaved. The strips of road marking are placed on the hot asphalt and rolled into the pavement itself. But this, too, has its drawbacks, according to Malone. "As you can imagine, we would not want to use these where we are anticipating traffic growth that would lead to revisions in the roadway markings prior to the next resurfacing," he said.
Finally, we come to raised pavement markers, which Malone said "also work very well." These last a long time and are readily seen in all but the worst weather. While expensive, "they are becoming more practical to install as more contractors obtain the equipment necessary to install them."
While it would be nice to say that there is a solution to poor road marking visibility and that the county has plans to put it into place, it seems as if the technology has a way to go. The answer comes down to individual drivers. When it is raining or snowing, especially at night, you need to drive that much more slowly and carefully.
What's your traffic trauma? Contact Jody K. Vilschick at firstname.lastname@example.org or send faxes to 410-715-2816. Technophobes can mail letters to Traffic Talk, The Sun in Howard County, 5570 Sterrett Place, Suite 300, Columbia 21044.