To the delight of the public, Starpath is being tested on 1,615 square feet of an existing path through Christ's Pieces municipal park in Cambridge, England.

To the delight of the public, Starpath is being tested on 1,615 square feet of an existing path through Christ's Pieces municipal park in Cambridge, England.

Credit: Lee Durant / Courtesy Pro-Teq Surfacing

Illuminating the outdoors can be a good—and necessary—thing in areas of pedestrian and vehicular traffic. While NighTec Leuchtsteine’s luminous pavers, Studio Roosegaarde’s Smart Highway, and BIG’s Digital Interactive Roadway are either still in the early stages of development or have proven too costly to implement market wide, U.K.–based Pro-Teq Surfacing has a solution that literally dazzles.

Starpath is a surfacing product that is sprayed onto common paving materials, such as concrete, asphalt, or timber, and it costs just under $11 per square foot. The elastomeric substance contains luminescent aggregates that absorb ultraviolet radiation during the day and release low-level lighting in the evening via photoluminescence, a process by which a material absorbs and releases photons, moving from a heightened energy state to a lower one, over time. Once the UV light penetrates Starpath’s aggregate, the treated surface will glow for up to 16 hours if blue or green aggregate is used; other colors are available but their glow is shorter lived.

Starpath can revive degraded pathways with a smooth, anti-slip coating, according to Pro-Teq. Applicators must wear face masks to filter the polyurethane-based mixture’s fumes, but the coating is inert once applied and should last at least a decade before re-application is needed.

  • Since Starpaths brightness depends on the strength of the solar energy it absorbs, its output at night can vary.

    Credit: Source: U.S. Department of Energy

    Since Starpath’s brightness depends on the strength of the solar energy it absorbs, its output at night can vary.

The product adjusts to ambient light levels, Pro-Teq owner Hamish Scott said in an October 2013 press release. It’s “almost like it has a mind of its own,” he said. “[T]his is pure nature doing its work.”

Although Starpath represents a notable improvement in self-illuminated surfacing products, the diffused and low light output is inadequate for pedestrian safety, which requires lighting levels that clearly reveal the features and behavior of other pedestrians. However, the technology may allow for a reduction in the number and frequency of streetlights and could even eliminate pedestrian lighting in areas designated as safe. Such a change would not only reduce energy consumption, but also please dark-sky advocates, revealing stars in the nighttime sky as well as on the ground.

Editor's note: This article appeared in the March 2014 issue of ARCHITECT and represents an updated version of Blaine Brownell's Feb. 13 Mind and Matter post on Starpath.