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Older Driver Safety: Reflective Posts and More

As the world’s population ages, the need for reflective posts and other visibility enhancing measures becomes increasingly acute.  This is due to the fact that one of the primary consequences of aging is diminished visual acuity.  A recent study performed by the Federal Highway Administration (FHWA) reported the following facts:

  • Starting at age 20, the volume of light required to see clearly doubles every 13 years.  This means that a 59 year old motorist must have eight times the amount of light a 20 year old needs to see the same object.
  • By the year 2020, 20% of the US population, or around 60 million persons at the time, will be 65 or older.  Most of those individuals will continue to drive, many of them well into their 80s or even beyond.  This is especially true in rural and suburban areas, where mass transit services are limited.
  • There is already a proven correlation between age and the likelihood of being in a motor vehicle accident.  For example, in the period from 2005-2008, almost half of all traffic fatalities occurred to drivers more than 40 years old.


In summary, America’s highway system must adapt to serve the needs of aging drivers in order to maintain current safety levels.


Current measures being taken

Enhanced retroreflectivity is only one of many changes being made to the nations’ road system to make it more accessible to older drivers.  Other actions being taken include:

  • Installing larger traffic signals to improve their color contrast and target value.
  • Adding more signals to roads with three or more through lanes.
  • Installing additional overhead signs along major highways.
  • Using sheeting materials with higher retroreflectivity standards.
  • Using fluorescent signage in roadwork zones.
  • Installing larger and more numerous channelizing markers to mark work zones.
  • Installing more highly reflective pavement markings on high-speed/high-volume roadways.
  • Using wider markings on high-speed/high-volume roadways.


For the future

The changes outlined above will be bolstered by the increased use of enhanced retroreflective materials for road signage.  In particular, prismatic sheeting will replace the old standard, encapsulated sheeting.  This is due to the many benefits that prismatic materials offer, which include:

  • Improved light return for all lanes of approaching traffic, from infinite greater array of observational angles.
  • A doubling of sign visibility during the hours from dusk to dawn.
  • Improved visibility during daylight hours as well, especially when prismatic sheeting is imbedded with fluorescent elements.  This is due to the fact that fluorescent substances return short-wavelength light as longer-wavelength light, rather than absorbing it, as is the case with traditional materials.
  • Enhanced visibility of pavement markings during periods of precipitation.  This is especially important since accidents are three times more likely to occur when roadways are wet than otherwise.


Additional factors affecting sign visibility and legibility

Reflectivity is only one of many criteria used to gauge how easily signs can be seen and understood.  Other factors include:

  • Contrast ratios of background vs. legend
  • Font type and size
  • The stroke width-to-height ratio
  • Letter and word spacing
  • The use of uppercase vs. lowercase letters
  • The use of text as opposed to symbols


To make roadways safer for older drivers, traffic highway officials will need to address each of the above areas.  For example, signs must offer greater contrast between their legends and backgrounds, larger, more easily distinguished fonts, and uppercase as opposed to lowercase letters. 

In addition, reflective posts and pylons must become larger and more numerous.  Signs that display symbols rather than text should be used more frequently as well.  By implementing these and other traffic safety measures, America’s roads can continue to serve the needs of all motorists well into the future.