What is a retroreflectometer?
In the most simple of terms a retroreflectometer is an instrument that assesses a pavement marking or sign’s nighttime visibility.
These instruments provide an accurate visibility assessment by measuring the retroreflectivity of the material tested.
This is done by emitting light toward the object at specific angles and distances known as 30-meter geometry. Then calculating the intensity of the returned light to the instrument’s sensor.
Retroreflectometer comes in three basic forms. A goniometer is used to measure a variety of materials in a laboratory environment. A handheld or portable unit that is manually operated by field personnel. And a mobile or dynamic unit that operates from a moving vehicle.
Signs and pavement markings are seen by the motorist from different angles. Therefore, we measure their visibility by different angles, and with different instruments. So no, sign and pavement marking retroreflectometers are not interchangeable.
Today’s retroreflectometers are often designed to collect far more than just retroreflectivity measurements. This additional information is dependent upon the retroreflectometer’s features. The most common features include; Push button or touchscreen user interface. Storage and transfer of data capability. Temperature and humidity sensors, as these environmental conditions can affect the material’s retroreflectivity. Project and user information for proper recording of the assessment. GPS for Geotagging mapping of where the measurement took place.
Extraordinary features could include an internal printer for field report printing. Compass and level to verify proper instrument alignment. And even a high-resolution camera for taking pictures of the signs or macro pictures of the pavement markings for further analysis. Some instruments also are provided with robust software to further visualize and analyze the data.
If you are considering the purchase of a retroreflectometer you will need to determine the form and features and even the finance in doing so. Here is a cool tool that can that asks all the right questions to insure you look for the right instrument. More information can be found on this Pavement Marking Resource Center web page.
To know “What Does a Retroreflectometer Cost?” read this article.