Special-purpose raised pavement markers

Internally illuminated pavement markers (IIPMs)

To ensure consistency on the network, internally illuminated raised pavement markers (IIPMs) are required to comply with Specification M29: internally illuminated pavement markers. This specification details size, function, and performance requirements for IIPMs.

Specification M29: internally illuminated pavement markers

Internally illuminated pavement markers can be powered by either:

• Type C Powered Systems – markers connected to or hard-wired to a typically extra low-voltage system. LEDs are powered via an extra low-voltage wire installed beneath the pavement surface set along the line of the markers to which the markers are hard wired. This can include markers that may be powered by a remote solar powered system;
• Type I Powered Systems – to avoid the need to individually hard wire every individual active marker into a power system, active pavement markers can also be “Inductively Powered”. LEDs are powered via an inductive cable, installed beneath the pavement surface, set along the line of markers, powering the markers without the need for a hard-wired connection. This may include markers that are powered by a remote solar powered system; or
• Type S Powered Systems – markers where the LEDs are activated via a “Solar Panel” incorporated in the upper surface of each individual marker designed to charge electric cells within the marker.

IIPMs use one of the above methods to illuminate, typically, light emitting diodes (LEDs) that provide delineation versus the retroreflective lenses of retroreflective raised pavement markers. When activated, the LEDs can be lit constantly or be set to a specific flashing rate to add urgency to a given condition.

Although some IIPMs remain lit permanently, many are activated by some form of “on / off” switching methodology such as the use of a photometer, measuring decreasing daytime light levels; by a timing device, as used for many traffic tidal flow systems; by the presence of a pedestrian; or by unique weather conditions where a marker can be activated when a particular road surface temperature/condition becomes evident.

These temperature and moisture-sensitive IIPMs activate a flashing blue marker to warn of ice forming conditions. The flashing blue light warns when moisture is present and the ground surface temperature has dropped to ice forming temperatures, suggesting a potentially dangerous road condition may exist in the area.

Other systems can be activated by the presence of a pedestrian waiting at a pedestrian crossing. Their presence on a pressure pad activates a specific layout of IIPMs which light to warn an approaching motorist that a pedestrian is at the crossing.

In special circumstances, such as in tunnels or where centrally located end terminals are particularly at risk, IIPMs may be considered in lieu of RRPMs.

As technology develops it is expected that there will be an increasing range of IIPMs available. Because of the potential for confusion with other types of retroreflective markers, it is important that any installations of IIPMs comply with the requirements of the TCD manual or are independently approved by Waka Kotahi NZ Transport Agency. In general, the requirements for the spacing and placement of IIPMs will be the same as for conventional RRPMs.